KR810000404B1 - Process for mn-al-c alloys magnet - Google Patents

Abstract

An anisotropic permanent magnet of an Mn-Al-C alloy containing 68.0 % to 73.0 % by weight of manganese, (1/10 Mn-6.6) % to (1/3 Mn-22.2) % by weight of carbon, and the remainder aluminum are rendered to anisotropic by deforming it plastically at a temperature of 530 - 830≰C. The permanent magnet has excellent mechanical characteristics and magnetic properties that the (BH) max is above 6.0 x 106 G.Oe up to about 9.2 x 106 G.Oe in its bulk state.

Description

Preparation of Manganese-Aluminum-Carbon-Based Alloy Magnets

1 is a graph showing the relationship between the grain size and the amount of carbon in a manganese-aluminum-carbon alloy casting made of 72.0% manganese and 0.1 to 2.5% carbon.

FIG. 2 is an optical micrograph of εс (M) phase.

3 is a relationship between the strain in the pressing direction and the pressing time when the ε (M) single crystal is processed at high temperature.

4 is a diagram showing the process of change of crystal structure in εс-ε'c → τc transformation.

5 is an optical microscope image of τc (M).

6 is a relationship between the pressing direction and the saturation strain.

7 is a ternary composition of a manganese-aluminum-carbon alloy.

The present invention relates to a method for producing a manganese-aluminum-carbon (Mn-Al-C) alloy magnet having excellent magnetic properties, temperature characteristics, stability, mechanical properties, weather resistance, and corrosion resistance, and in particular, improved magnetic properties and mechanical properties. .

Manganese-aluminum alloy magnets known in the prior art are made from 60 to 75% by weight of manganese (hereinafter referred to as only%) and the remainder of aluminum, and its high-temperature phase (lattice constant a = 2.69A, c = 4.38A, c / a = It is decomposed in non-magnetic growth of 1.63 which is called ε phase and normal temperature phase (AlMn (γ) phase (hereinafter referred to as γ phase) and β-Mn phase). The metastable phase (which is referred to as τ phase below the lattice constant a = 3.94A, c = 3.58A, c / a = 0.908) is referred to as the τ phase. The τ phase as a metastable phase obtained by heat treatment is a magnetic phase having a Curie point of 350 to 400 ° C., which was discovered in 1955 by Kawano et al.

However, the magnetic properties of this manganese-aluminum-based alloy are about BHma × 0.5 × 10 ⁶ G.Oe, Bγ × 2200 G, and BHc × 600 Oe. It was only.

In addition, a method of forming or sintering powder after strengthening the coercive force by pulverizing these τ phases by cold was also developed, but isotropic in terms of their best magnetic properties. As it is, they are extremely low, such as BHma x 0.6 x 10 ⁶ G.Oe, Bγ x 1700G, and BHc x 1250Oe, and because they are powder molded products, they have low mechanical strength and are far from practical areas. In addition, an attempt was made to improve magnetic properties by anisotropically forming these manganese-aluminum alloy magnets, and to apply a strong cold working to the τ phase (magnetic phase) (hereinafter referred to as a cold working method) or τ pulverized by cold A method of molding a powder of a phase in a magnetic field, or a method of sintering it (hereinafter, these are referred to as a powder molding method in a magnetic field) has been proposed.

However, these anisotropic methods also have the following difficulties, and therefore, it is difficult to use industrial manufacturing methods and they are not practical.

That is, among these isotropicization methods, the cold working method is a kind of intermetallic compound having an extremely hard and brittle mechanical property of manganese-aluminum alloy magnets, so even in the processing of 1% or less, cracking or breaking I), on the other hand, the degree of anisotropy depends on the cold working rate, and a large processing rate of 80% or more is usually required to obtain good magnetic properties. This results in destruction and crushing at. As a countermeasure, a rod-shaped τ-shaped manganese-aluminum alloy magnet is enclosed in a nonmagnetic stainless pipe, for example, 25Cr-20Ni stainless steel pipe, and the corrugation is sued as it is. Cold processing of strength of 85 to 95% or more, Br = 4280G, BHc = 2700Oe, BHmax ≒ 3.5 × 10 ⁶ G in the magnetization upper direction, that is, in the axial direction of the rod, that is, at right angles to the working pressure. It is known that anisotropic permanent magnets of the order of .Oe are obtained.

However, in this method, because of the steel working, the manganese-aluminum alloy in the pipe is in a powder state that is pulverized, and thus only a fine rod coated with a pipe such as stainless steel can be obtained. Moreover, since the cross section was uneven and expensive, it was not practical.

In addition, as a method of measuring these difficulties, hydrostatic extrusion processing of the τ phase of the manganese-aluminum alloy magnet at a temperature of 200 ° C. or less has been attempted, and there have been reports that a rod-shaped anisotropic manganese-aluminum alloy magnet has been obtained. The magnetic properties are only about BHmax ≒ (2.5 to 3.6) × 10 ⁶ G.Oe in the magnetization predominant direction, and require extremely complicated hydrostatic extrusion, which has not reached practical use.

On the other hand, the powder shaping method in the magnetic field is a method of mechanically pulverizing the τ phase (magnetic phase) of a manganese-aluminum alloy magnet, and then press-molding the powder particles in the magnetic field. BHmax ≒ 1.85 × 10 ⁶ G.Oe (Br ≒ 3050G, BHc ≒ 2390Oe) was reported in the superior direction, more complicated grinding process is required, and mechanical properties of permanent magnets obtained are also powder molded products. It is extremely fragile and has not reached practical use.

As for the manganese-aluminum alloy magnets as described above, manganese and aluminum-carbon alloy magnets having an excellent isotropic magnetic property in bulk form have been invented and described, for example, in US Pat. No. 3,661,567.

That is, according to US Pat. No. 3,661,567, the manganese-aluminum-carbon alloy magnet may be a polyatomic or more than tri-atomic composition containing other additives or impurities other than manganese, aluminum, and carbon. The composition ratios of manganese, aluminum, and carbon in polyalloy

An alloy in the range of is obtained as a bulk isotropic permanent magnet having excellent magnetic properties, stability, weather resistance and mechanical strength when manufactured under the following defined conditions.

In other words, manganese, aluminum, and carbon components are blended in the above composition range, and the carbon is forcibly dissolved in the molten metal by heating to at least 1380 ° C to 1500 ° C. Mold on.

The resultant cast body is heated to 900 ° C or more to a homogeneous high temperature phase, and then quenched by quenching at a cooling rate of 300 ° C / min or more from a temperature of 900 ° C or more to a temperature of 600 ° C or less.

This quenched alloy is heated in a temperature of 480 ° C. to 650 ° C. for a suitable time to be annealed, and is bulk in shape. Moreover, the manganese-aluminum-carbon alloy magnet isotropic and has magnetic properties of BHmax ≒ 1.0 × 10 ⁶ G.Oe or more. This magnetic property is more than twice that of an isotropic manganese-aluminum alloy magnet.

The present inventors have examined in detail the reason why the magnetic properties are improved especially when the manufacturing conditions of the manganese-aluminum-carbon alloy magnets are limited as described above. That is, it became clear that the manufacturing conditions and the magnetic properties are complicated and closely related as described below.

Therefore, in the case of manufacturing conditions where the existence of carbon is not appropriate, even if the composition ratio of manganese, aluminum and carbon is in the above-described range, and even if τ phase is sufficiently present, only magnetic properties as low as those of isotropic manganese-aluminum alloy magnets Not shown.

In order to obtain an isotropic permanent magnet having excellent magnetic properties in a manganese-aluminum-carbon alloy magnet, the phase present in the alloy is mainly

(1) Magnetic phase in which solid carbon is more than solid solution employed, i.e., the body-centered crystal phase described in US Patent No. 3,661,567 (except in the US Patent Specification, the unit crystal indicating the atomic arrangement of the magnetic phase) As the lattice, a representation of body-centered equations is employed. However, in the present specification, a representation of a face-centered equation, which is another representation of a unit crystal lattice representing the same atomic arrangement, is adopted. do.)

(2) The excess carbon in the remaining portion is a carbide other than aluminum carbide (Al ₄ C _3, etc.), which is a phase of Mn ³ Alc or similar face-centered cubic crystal obtained by extracting into fine granules or water droplets by annealing process, (1) It is evident that it is necessary to disperse and extract (2) in the form of fine grains or meshes mainly in the alloy.

It is evident that the alloy is in the above-described phase state not only for improving the magnetic properties but also for the stability of the magnetic phase.

The presence of this carbon was confirmed by X-ray diffraction, optical microscope, electron microscope and chemical analysis.

In addition, Mn ₃ Alc is a compound having a perovskite type face-centered cubic structure (lattice constant a = 3.87A), but a ferromagnetic material having a δo ( θ ) of 99.6 erg / g.Oe, but the Curie point is 15 ° C. at room temperature. Mn ₃ Alc itself does not contribute to the magnetism of the manganese-aluminum-carbon alloy magnet, even if it is present in the manganese-aluminum-carbon alloy because it is nonmagnetic.

Al ⁴ C ₃ is a carbide present in the manganese-aluminum-carbon alloy containing manganese in a range of 68.0 to 73.0% and containing carbon in excess of (1 / 3Mn-22.2)%. It is produced at a temperature above the freezing point of the carbon-based alloy, and within the temperature range below the freezing point, it does not form or disappear by heat treatment.

Al ₄ C ₃ is hydrolyzed by moisture such as moisture in the air to cause cracks in the alloy, and eventually, as the hydrolysis proceeds, the alloy eventually collapses.

The carbon employment limit of the magnetic phase in the manganese-aluminum-carbon alloy is 0.6% in the measurement of the loss coefficient by X-ray diffraction and 72% in the measurement of the Curie point by a magnetic balance. Where the composition of 70% manganese is 0.4%, it has been found that the carbon employment limit within the composition range of 68.0-73.0% manganese can be represented by a formula (1/10 Mn-6.6)%.

On the other hand, the solubility of carbon in the high temperature phase is generally the same as that of the magnetic phase at a temperature of 830 ° C, but 0.8 to 2.0% of carbon is dissolved in the temperature range of 900 to 1210 ° C, and the temperature is higher than 900 ° C. By overcooling by the quenching process, a high-temperature phase obtained by forcing solid solution of dissolved silver (1/10 Mn-6.6)% or more can be obtained.

In this manner, in the manganese-aluminum-carbon alloy, the high temperature phase in which the solid solution of carbon in the form of solid solution is more than (1 / 10Mn-6.6)% or more is abbreviated as εc phase and the high temperature phase containing less than carbon solution is employed. Distinguish from ε phase.

In addition, the magnetic phase which forcibly employ | adopted the above-mentioned solid solution carbon is abbreviated to (tau) c phase, and is distinguished from the (tau) phase of the magnetic phase containing less than the carbon solution dissolved.

When the above-mentioned annealing treatment is performed on the εc phase alloy, it is possible to obtain a phase state in which Mn ₃ AlC or similar face centered cubic phases are dispersed finely in the alloy or in the shape of water in the alloy mainly based on the τc phase described above. However, in the quenching process from a temperature above 900 ° C., when the temperature range of 830-900 ° C. is cooled slowly at a cooling rate of 10 ° C./min or less and then quenched at this temperature, or within a temperature range of 830 ° C. or above 900 ° C. At least 7 minutes, preferably at least 10 minutes, in the εc phase when quenched at the temperature, Mn ₃ AlC arranged in a layer by maintaining an interval of 1-10μ in parallel to a specific crystal plane of the εc (0001) plane in the εc phase Was extracted, and it became apparent by optical microscopy and X-ray diffraction that this layered Mn ₃ AlC has a crystal orientation relationship of εc (0001) // Mn ₃ AlC (111).

However, the above symbol // indicates that both crystal planes are in parallel relationship with each other, and is represented by the symbol which is below when the crystal plane of one phase and the crystal plane of another phase are in parallel relationship with each other (crystal plane) // (crystal plane). In addition, when the εc phase within the 1 ~ 10μ interval between the layered Mn ₃ AlC is observed in detail by the electron microscope, it is not clear by the optical microscope, but the electron microscope has the crystal orientation relationship as described above at the interval of 0.1 ~ 1μ. It was confirmed that the Mn ₃ AlC phase and a similar face center cubic phase were extracted on the εc (0001) plane.

As such, a heat treatment for extracting the Mn ₃ AlC phase into the layer, that is, cooling the temperature range of 830 to 900 ° C. at a cooling rate of 10 ° C./min or less, or maintaining it for at least 7 minutes in a temperature range of 830 ° C. or more and less than 900 ° C. The heat treatment to be referred to is specifically referred to as M treatment, and the phase state of [[epsilon c phase + layered Mn ₃ AlC phase] containing layered Mn ₃ AlC phase extracted by this M treatment is abbreviated as εc (M) phase.

It was confirmed by X-ray diffraction, X-ray microanalysis and chemical analysis that the amount of carbon in the εc phase of the matrix in the alloy of the εc (M) phase was reduced to near the carbon employed at high temperature at 830 ° C by M treatment. .

When the above-mentioned annealing treatment was performed on the εc (M) phase alloy, the εc phase of the matrix was transformed into a τc phase to become a magnet, but its magnetic properties were extremely low, and were similar to those of the isotropic manganese-aluminum alloy. .

When the phase state of the alloy after the annealing treatment was observed under an optical microscope, the layered Mn ₃ AlC phase before the annealing treatment remained intact, and the above-described fine granular or Mn ₃ AlC or a similar face-centered cubic phase of the water grating was Hardly recognized.

[τ c phase + layered Mn ₃ AlC phase] obtained by annealing of the εc (M) phase is abbreviated as τc (M) phase.

In addition, [τc phase + layered Mn ₃ AlC phase] is obtained even after slow cooling at a cooling rate of 300 ° C./min or less in the M treatment temperature range, for example, at a temperature of 830 ° C., and thus obtained [τ c Phase + layer phase Mn ³ AlC phase] is also abbreviated as τc (M) phase.

Therefore, in order to obtain an excellent isotropic permanent magnet in manganese-aluminum-carbon alloy magnets, instead of simply obtaining a τ phase or a τc phase, the annealing treatment is performed with the epsilon c phase in which carbon is forcibly employed, and the Mn phase is mainly Mn. ₃ AlC or similar face-centered cubic phase is finely dispersed in τc phase into fine grains or water droplets, and extracted to make τc phase refinement and refinement.

The magnetic properties of the manganese-aluminum-carbon alloy magnets thus obtained are bulk isotropic, which is BHmax-1.0 × 10 ⁶ · G Oe or more, and the mechanical strength thereof is hardness HRc = 45 and tensile strength = 1. It was-2 kg / mm <2>, elongation degree = 0, a constant pressure = 100 kg / mm <2>, and a drag force = 7 kg / mm <2>.

However, manganese-aluminum-carbon alloy magnets are serious drawbacks, and in order to further improve their magnetic properties, their performance as isotropic magnets has reached a limit, and magnetic properties are hardly achieved by any of the above-described cold working methods or powder molding methods. There was no improvement or rather deterioration, and no improvement in performance due to anisotropy was expected.

The present invention further develops the manganese-aluminum-carbon alloy magnet of US Patent No. 3661567, and provides a method for producing a new high-performance permanent magnet that has dramatically improved its magnetic properties.

The present invention provides a method for producing a highly mobile anisotropic manganese-aluminum-carbon alloy magnet having a high mobile anisotropy having a magnetic property of BHmax-6.0 × 10 ⁶ G .Oe in a bulk phase of 9.2 × 10 ⁶ G.Oe or more. It is.

In addition, the present invention provides a method for producing anisotropic manganese-aluminum-carbon alloy magnets having magnetic properties of BHmax-4.8 × 10 ⁶ G .Oe in bulk and having 6.3 × 10 ⁶ G.Oe.

According to the present invention, the biaxial direction for magnetization as an isotropic magnet can also be arbitrarily selected.

In addition, the anisotropic magnets provided by the present invention, anisotropic magnets having extremely high anisotropy degree, and their intermediate-stage permanent magnet groups have a specific gravity of 5.1, and have an energy per weight even when compared with conventional permanent magnet groups. Permanent magnet group with extremely high magnetic properties, reaching the highest level, for example, having energy per weight of 2-3 times that of anisotropic (Ba, Sr) ferrite magnets and 1,5-2 times that of alnico magnets. to be.

The present inventors found that manganese-aluminum-carbon alloy magnets are abnormally large in a specific temperature range of 530 ° C to 830 ° C even though the alloys of the intermetallic compound type are extremely hard and have no plasticity as described above. The discovery of the presence of a new specific phase state with sintering, and this new phenomenon leads to unpredictable magnetic properties, which is unpredictable by high temperature processing in the anisotropic region and also by the appropriate and effective utilization of the presence of carbon. It was successful in obtaining a bulk anisotropic manganese-aluminum-carbon alloy magnet having

The rapid improvement of magnetic properties by the high temperature processing as described above is a new phenomenon due to the unique mechanism of manganese-aluminum-carbon alloy magnets. For example, the manganese-aluminum alloy magnets are slightly baked at 580 ° C or higher. In the high temperature processing of 530 ° C. or higher, the improvement of the magnetic properties could not be confirmed at all, but rather the magnetic properties were significantly reduced.

Next, the present invention will be described in more detail.

Comparative Example 1

The chemical analysis produced a single crystal of the εc phase of the manganese-aluminum-carbon alloy having a composition of 72.28% manganese, 26.64% aluminum and 1.08% carbon.

As a result of examining the factors for obtaining the εc single crystal of the manganese-aluminum-carbon alloy, it was found that the crystal growth required for the single crystallization is dependent on the carbon solubility.

That is, in order to obtain the εc single crystal, the amount of carbon must be in the range of (1 / 10Mn-6.6)% to (1 / 3Mn-22.2)% (wherein Mn 68.0-73.0%), and this carbon is forcibly dissolved. It is essential that the process of heating at least 1380 degreeC or more to 1500 degreeC at least 1 time as a melting temperature to make it melt | dissolve.

For example, when the amount of carbon employed is less than (1 / 10Mn-6.6)%, the ε phase is difficult to obtain crystal growth, and it is difficult to obtain a single crystal. It has been found that the manganese-aluminum-carbon alloys which are sufficiently dissolved at a melting temperature of not lower than 0 ° C. are remarkable in coarsening of crystal grains. Therefore, the epsilon c single crystal can be easily obtained by cooling the capacity of this alloy from one end by the so-called bridgeman method or the cooling mold method.

The crystal growth of the εc phase is, for example, in the case of polycrystals under ordinary casting conditions, as shown in FIG. It is admitted that the grain size increases with increase, but if the carbon amount exceeds (1/3 manganese-22.2)%, it is not preferable because excess carbon forms aluminum carbide Al ₄ C ₃ as described above.

Therefore, the amount of carbon for obtaining the εc single crystal without defect is limited to the range of (1/10 manganese-6.6) to (1/3 manganese-22.2)% described above. In order to forcibly solidify these carbons, it is necessary to go through a step of heating at a temperature of at least 1380 ° C or higher, and at a melting temperature of less than 1380 ° C, it is not possible to forcibly solidify more carbon.

Once forcedly dissolved carbon is slowly adsorbed at low cooling rate or maintained at a constant temperature, it is not admitted to extract it as carbon element or Al ₄ C ₃ in the temperature range above 900 ℃.

Therefore, in order to obtain εc single crystals, each element may be blended and heated to 1380 ° C. or higher, followed by alloying, and then monocrystallization. The aluminum-carbon alloy may be redissolved and used in this case. As the heating temperature for epsilon c single crystallization, a temperature of 1380 ° C or higher is not necessarily required, and heating to a temperature of 1210 to 1250 ° C or higher is sufficient.

The temperature control conditions for cooling and solidifying the capacity of these manganese-aluminum-carbon alloys from one end to obtain εc single crystal are 0.5 to 10 cm / in a temperature range of 1150 to 1250 ° C. under a temperature gradient of 5 to 200 ° C./cm. The melt is solidified from one end at a drop rate of hr, or the temperature range is solidified from one end at a cooling rate of 10 to 100 ° C./hr to obtain a single crystal. The single crystal is slowly cooled to 900 ° C. and then 900 A temperature range of 900 to 500 ° C. was cooled at a temperature of 300 ° C. to 3000 ° C./min to be quenched to a temperature of 500 ° C. or less, and a columnar εc single crystal having an outer diameter of 35 mm could be easily obtained.

The 8x8x8mm cube sample which has (0001), (1100), (1120) plane was cut out from the epsilon c single crystal obtained as mentioned above.

This cut εc single crystal sample was subjected to annealing at 600 ° C. for 1 hour to obtain a τc phase and to measure magnetic properties.

Magnetic characteristic value

Br = 2750G BHc = 1350Oe BHmax = 1.1 × 10 ⁶ GOe

And magnetic properties equivalent to those of a conventional polycrystalline isotropic manganese-aluminum-carbon alloy magnet.

In the optical microscope structure of the sample after annealing, extraction of the fine granular or mesh-like Mn3AlC phase was recognized similarly to the structure of an isotropic magnet.

However, the X-ray diffraction results show that the diffracted ray intensities of the Mn3AlC phases differ depending on the sample surface to be diffracted, and that there are slightly more Mn3AlC phases having an orientation having an εc phase before annealing and εc (0001) // Mn3AlC (111). It became.

In addition, even in the samples subjected to the above-described experiments by changing the cut surface and the annealing conditions, all of them were isotropic magnets, and improvement of magnetic properties was not recognized.

Comparative Example 2

An epsilon c single crystal was made in the same manner as in Comparative Example 1, and subjected to M treatment for holding it at a temperature of 830 ° C. for 20 minutes, followed by quenching at a cooling rate of 300 to 3000 ° C./min at this temperature.

The obtained single crystal is in a state in which the Mn3AlC phase is regularly extracted to the (0001) plane of the epsilon c single crystal in the layered manner (expressed as the epsilon c (M) single crystal) as described above.

εc (0001) // Mn ₃ AlC (111)

As a result, it was confirmed by the x-ray diffraction, the x-ray trace analysis, the optical microscope, and the chemical analysis that the amount of carbon on the epsilon c phase of the matrix was reduced to the near solution.

FIG. 2 is an optical microscope histogram (magnification 1000 times) showing a state in which Mn ₃ AlC phases are extracted in a layer of εc matrix.

In the εc (M) single crystal obtained as described above, an 8 × 8 × 8 mm cube sample having the (0001), (1100), and (1120) planes of εc was cut off, and subjected to annealing treatment at 570 ° C for 1 hour. τc (M) phase was obtained.

The annealing treatment transformed the εc phase of the matrix into a τc phase, but it was confirmed by optical microscopy and X-ray diffraction that layer Mn ₃ AlC (no change in phase) was observed.

The magnetic properties of the sample on τc (M) obtained are completely isotropic

Br = 2550G BHc = 800Oe BHmax = 0.67 × 10 ⁶ G.Oe

The magnetic properties were lower than that of a conventional polycrystalline isotropic manganese-aluminum-carbon alloy magnet.

In addition, even when the cut surface and the annealing conditions were variously changed, all of them were isotropic, and no improvement in magnetic properties was observed.

Example 1

Chemical analysis showed that the single crystals of εc (M) on manganese-aluminum-carbon alloys having a composition of 72.10% manganese, 26.78% aluminum and 1.12% carbon were prepared in the same manner as in Comparative Example 2 Several cubic samples of 10 × 10 × 10 mm having three planes parallel to the three crystal planes of (3304), (1120), and (3308) were cut out.

One sample cut out was pressurized at a pressure of 30 kg / mm ² using a hydraulic up-and-down press device in a direction perpendicular to the surface at a temperature of 550 ° C. (3304), and subjected to high temperature pressurization in εc (M). As shown in the deformation curve of the figure, the phenomenon of rapid shrinkage in the pressurization direction occurred within a few minutes (point B) at the time of pressurization (point A) was found to cause rapid and significant plastic deformation.

The rapid contraction in the pressing direction reached saturation at a strain rate of -15% indicated by a change rate of the length of the sample before and after pressing (point C), and hardly deformed even if the pressing time was further increased. (D point) was a low magnetic property after measuring the cutting property of the sample after high-temperature processing, but the sample was subjected to an annealing treatment at a temperature of 570 ° C., which generally had a magnetization advantage in a direction perpendicular to the pressing direction. An anisotropic magnet with extremely excellent magnetic properties of directionality was obtained.

In this way, in order to investigate in detail the phenomenon of rapid and significant plastic deformation due to the high temperature processing of εc (M) and the phenomenon of becoming a unidirectional anisotropic magnet when the annealing treatment is performed, the strain is changed in various ways as follows. The experiment was carried out as follows, and the phase state of the sample during the processing was investigated.

First, the sample that was pressure-strained to point B just before the rapid plastic deformation started, and the sample S ₂ that was pressure-strained to point E between the middle point S ₁ and B and C pointed to the point immediately before point C where rapid plastic deformation ends. The sample subjected to pressure deformation is referred to as S ³ , and the sample subjected to pressure deformation to point D described above is referred to as S ₄ , respectively.

Strain in these samples S ₁ is -1.9%, S ₂ is -7.3%, S ₃ was S -14.6% ₄ 15.0%.

As for the shape of the sample after processing, the orientation of all samples is recognized in the elongation, and in particular, in the samples of S ₃ and S ₄ , the elongation in the direction corresponding to the direction perpendicular to the 3308 on the pressing side is remarkable, In the direction corresponding to the direction perpendicular to), a slight elongation was only recognized. X-ray diffraction was performed on these four samples, and the state of the sample after processing was examined. As a result, completely new diffraction lines were found in the samples of S ₁ , S ₂ , and S ₃ , which did not appear in the conventional manganese-aluminum alloy.

The analysis of this completely new X-ray diffraction line shows that the crystal structure is a Stroketu Berryheed type, which has a lattice constant of a = 4.371A, b = 2.758A, C = 4.582A belonging to type B19 (Mgcd type). Due to the presence of a new phase having a structure, the existence of a completely new phase different from each of phases ε, εc, τ, τc and carbides such as Mn ₃ AlC is not apparent.

In addition, this tetragonal phase is an intermediate phase of the εc → τc transformation process, and it is evident that the εc phase of irregular hexagonal structure is transformed, and the εc → ε'c transformation is irregular-regular transformation.

Ε'c refers to the new rule of thumb.

Table 1 shows the X-ray diffraction results by the powder method of ε'c phase.

In the sample of S ₁ , only the diffraction lines of the new ε'c phase except for the diffraction lines due to the layered Mn 3 AlC phase, and the ε'c phase are unidirectional crystals, εc phase of the matrix before pressing and ε'c of the matrix after pressing. In between

εc (0001) // ε'c (100) εc [0001] // ε'c [100]

It is now clear that there is a decision defense relationship.

TABLE 1

In the sample of S ₂ , the diffraction lines of the ε'c phase and the τc phase were present in addition to the diffraction lines of the layered Mn ₃ AlC phase, and both of the ε'c phase and the τc phase were unidirectional.

In the sample of S ₃ , diffraction lines by a small amount of ε'c phase and a large amount of τc phase exist in addition to the diffraction lines by the layered Mn ₃ AlC phase, and ε'c phase and τc phase are both unidirectional as S _2. It was.

Between these unidirectional ε'c phase and τc phase

ε'c (100) // τc (111)

There is a specific decision orientation relationship.

In the sample of S ₄ , except for the diffraction lines due to the layered Mn ₃ AlC phase, only the diffraction lines due to the τc phase, and the τc phase had substantially one-way direction. In addition, the angle of τc phase X-ray diffraction lines in the samples of S ₂ , S ₃ , and S ₄ deviates slightly from the angle of diffraction lines of the normal τc phase in isotropic manganese-aluminum-carbon alloy magnets. The difference was recognized.

The samples after these processing were subjected to an annealing treatment (or an annealing temperature of 580 ° C.) under normal atmospheric pressure. The magnetic properties of the samples after annealing improved with an increase in an annealing time, so that S ₁ was 18 hours and S ₂ was 24 hours. , S ₃ is 30 hours, S ₄ is an unwinding time of 15 hours, and extremely excellent anisotropic magnets having the maximum magnetic properties shown in Table 2 were obtained.

In addition, the right angle direction 1 of Table 2 is a measurement direction corresponding to the direction perpendicular to the (1120) plane before the pressurization at a right angle with respect to the pressurization direction, and the right angle direction 2 is at right angles to the pressing direction (2308). Each measuring direction corresponding to the direction perpendicular to the plane is displayed.

TABLE 2

Among them, the sample after annealing of S _{3 has} a unidirectional τc (M) phase, i.e., τc (M, in which the C-axis, which is the biaxial for magnetization of the τc phase of the matrix, is arranged at an angle of 82 ° C as the result of X-ray diffraction. ) Single crystal, cut and measured for magnetic properties in the axial direction (C axis direction)

Extremely excellent magnetic properties were obtained.

In this unity sample, the magnetic torque was measured by cutting the disc sample containing the magnetization superiority direction in a direction parallel to the disc surface, and the measured anisotropy constant was 1.07 × 10 ⁷ erg / cm 3.

Similarly, the magnetic torques of the samples after annealing of S ₁ , S ₂ , and S ₄ were measured. The magnetic anisotropy constants were 0.93 × 10 ⁷ erg / cm 3, 0.97 × 10 ⁷ erg / cm 3 and 0.95 × 10 ^{7, respectively.} erg / cm 3, and the anisotropy degree of the single crystal was expressed by the ratio of the magnetic anisotropy constant of the single crystal, that is, 1.07 × 10 ⁷ erg / cm 3, in which all samples had extremely high anisotropy ratio of 0.9 or more.

The crystallographic direction of the? C phase after the annealing treatment was the same as the crystallographic direction of the? C phase before the annealing treatment, and the change in the crystallographic direction of the? C phase by the annealing treatment was hardly recognized.

In addition, as a result of detailed investigations on the rapid plastic deformation phenomenon and the formation and formation of unidirectional anisotropic magnets in the high temperature processing of τc (M) phase, these phenomena have a specific crystal orientation relationship εc → ε'c → It became clear that the εc transformation was followed.

In other words, when a single crystal on εc (M) is pressed in the direction described above, the matrix is caused by an irregular-regular transformation where εc → ε'c.

εc (0001) // ε'c (100)

εc [0001] // ε'c [100]

Is a single crystal of? 'C having a crystal orientation relationship.

This εc → ε'c transformation corresponds to the process from point A to point B in FIG. 3, and the shrinkage in the pressing direction is not too large. In addition, the ε'c phase is ε'c (100) // τc (111) due to the ε'c → τc transformation in which the atomic plane moves by the distance in the direction of [001] from the specific crystal plane of (100). It transforms into a single crystal of τ c having.

Atomic plane movement in a specific direction in this specific crystal plane occurs rapidly like an avalanche, causing a rapid contraction in the pressing direction from point B to point C.

And the contraction of the pressurization direction stops at the time when all the epsilon'c atomic shifts were completed and transformed into τc, that is, point C.

After all the epsilon'c transformed into τc, almost no deformation was continued even when the pressurization was continued.

4 is a diagram showing a process of changing the crystal structure in the above-described transformation of εc → ε'c → τc.

(1) is εc, (2) is ε'c, (3) is a view showing the crystal structure of each phase of τc, (1) is on the (0001) plane and (1120) plane of the εc phase, (2) shows the (100) plane and (010) plane of the epsilon'c phase, and (3) is the figure seen from the perpendicular | vertical direction with respect to the (111) plane and (110) plane of (tau) c phase, respectively.

The solid line indicates the respective crystal lattice, the dotted line indicates the atomic position relationship, and the arrow indicates the direction of movement of the atomic plane.

The double circle mark? Denotes the atomic position of manganese or aluminum in an irregular state, and the white circle mark? And black circle mark? Indicate the atomic positions of aluminum and manganese in a regular state, respectively.

In addition, the atomic position of carbon in solid solution state is abbreviate | omitted.

After processing, τc is extremely low in magnetic properties and becomes τc with fewer defects due to annealing, resulting in an anisotropic magnet having extremely excellent magnetic properties.

By this mechanism, it has been found that a rapid plastic deformation phenomenon occurs and a unidirectional anisotropic magnet is formed.

Therefore, the optical microscope structure of the sample after such high temperature processing is extremely even and smooth except that the presence of the layered Mn ₃ AlC phase is recognized as shown in FIG. 5 as a texture photograph with a magnification of 1000 times. As can be seen, no tissues such as dividing or breaking crystals or twinned tissues by slip bands were recognized.

Rapid plastic deformation in the high temperature processing of εc (M) is not a deformation due to sliding or twining, which is found in ordinary plastic deformation of other metals or alloys, but a deformation due to the ε'c → τc transformation. It has been found that the harmony of deformation is due to a mechanism that is completely different from the saturation of deformation due to work hardening of ordinary metals or alloys.

Moreover, it turned out that the anisotropy of the extending | stretching direction in the sample after the above-mentioned processing is due to the atomic surface movement to a specific direction in (epsilon) 'c → (tau) c transformation.

In addition, in the samples of S ₁ and S ₂ , shrinkage in the original pressurization direction was constant by the unwinding treatment, and after unwinding, S ₁ contracted by 5.5% and S ₂ by 6.0% as compared with before unwinding.

When this phenomenon is transformed by pressurization to the ε'c phase, τc which has a directionality is formed even after the ε'c → τc transformation without pressurization.

In other words, the annealing treatment after processing has no orientation effect, but since S ₁ and S ₂ are formed in the ε'c phase or the mixed phase of the ε'c and τc phases oriented by high temperature processing as described above, It is thought that the directional c phase formed by the ε'c → τc transformation. However, in order to obtain a unidirectional anisotropic magnet having the most excellent magnetic properties, it is important to work until just before reaching the saturation strain, that is, just before the point C in FIG.

Example 2

The high temperature processing experiment similar to Example 1 was performed by changing the pressurization direction, pressurization temperature, and pressurization pressure.

By chemical analysis, a single crystal of the εc (M) phase of manganese-aluminum-carbon alloy having a composition of 71.93% of manganese, 27.02% of aluminum and 1.05% of carbon was prepared in the same manner as in Comparative Example 2, and the single crystal of εc (M) phase The single crystal sample for pressurization of a cube or cube in which one side is 5-12 mm was cut out.

Pressurized sample has a surface

(a) plane perpendicular to the pressing direction

(b) a plane in which the crystal plane including the pressing direction and εc [0001] direction is parallel

(c) faces perpendicular to (a) and (b)

It cut off so that it might have three sides of (a), (b), and (c) which were orthogonal to each other. The temperature range of 500-850 degreeC was pressurized and deform | transformed by applying the pressure of 10-40 kg / mm <2> by the hydraulic up-and-down press apparatus, and the annealing process was carried out in the temperature range of 550-650 degreeC.

With respect to the sample after annealing, the magnetization superiority direction was determined by measuring X-ray diffraction or magnetic torque or by measuring the magnetization curve in various directions, and the magnetic properties in the magnetization superiority direction were measured.

Table 3 shows the high temperature processing conditions (pressure direction, pressurization temperature, strain rate in the pressurization direction) and magnetic property values after the annealing treatment and the magnetization superiority direction in each sample.

In order to clarify the direction, the pressing direction is the angle between the pressing direction and the εc [0001] direction and θ ₁ , and the projection axis and εc [1100] on the εc (0001) plane in the pressing direction. and the angle formed between the direction θ _2, expressed as angle of θ ₁ and θ _2.

For example, the pressing direction of θ ₁ = 90 ° and θ ₂ = 0 ° is the direction perpendicular to the εc (1100) plane, and the pressing direction perpendicular to the (3304) plane in Example 1 is approximately θ _1. = 55 °, θ ₂ = 0 °.

TABLE 3

θ ₁

90°,θ°

θ ₂

30°의 각도범위내로 하였다. θ ₁ and θ ₂ are θ ° from the symmetry of hexagonal crystals.

θ ₁

90 °, θ °

θ ₂

It was in the angle range of 30 degrees.

All the pressing methods outside this angle range can be substituted for the pressing direction within the angle range from the symmetry of the hexagonal crystal.

In the experimental results in which the pressing direction was changed, anisotropic magnets were obtained in most pressing directions, but a large difference was observed in the magnetic characteristic values depending on the pressing direction.

θ ₁

90°, 0°

θ ₂

15°의 각도 범위내에 있는 경우는 자와우위방향의 BHmax.가 6×10⁶G.Oe이상의 극히 뛰어난 자기특성을 갖는 이등방성 자석이 되었다.Especially the pressing direction is 35 °

θ ₁

90 °, 0 °

θ ₂

When it is within an angle range of 15 °, the anisotropic magnet has extremely excellent magnetic properties of 6 × 10 ⁶ G.Oe or more in the direction of magnetism and the right direction.

On the other hand, in the pressing directions of θ ₁ = 0, θ ₂ = negative and θ ₁ = 90 ° and θ ₂ = 30 °, the magnetic properties in the direction perpendicular to the pressing direction were almost isotropic.

The direction of magnetization superiority, which indicates the maximum magnetic characteristic value, is different depending on the pressing direction. For example, in sample S _{9 having} θ ₁ = 55 ° and θ ₂ = 0 °, the direction of the magnetizing direction is approximately 82 ° with the pressing direction. In sample S ₁₄ with θ ₁ = 70 ° and θ ₂ = 0 °, respectively, they were in the direction of pressing direction and about 70 °, and all of them were unidirectional τc (M) with many τc [001] axes in the magnetizing right direction. It was an award.

In the sample S ₁₅ of θ ₁ = 90 ° and θ ₂ = 0 °, the magnetization upper direction is in the pressing direction, but the τc [001] axis is not in the pressing direction, and is approximately 37 with the pressing direction with the pressing direction as the symmetry axis. It was in two directions.

θ ₁

90°, 0°

θ ₂

15°의 각도 범위에 있는 경우 εc→ε'c 변태에 의해 형성되는 매트릭스의 ε'c상은 대체로 일방향성으로 이것에 이어지는 ε'c→τc변태에 의해 일방향성 혹은 2방향의 τc상이 형성된다.The reason why the magnetism of the magnet after the high temperature processing of the epsilon c (M) phase and the subsequent annealing treatment is increased along the pressing direction depends on the quality of the orientation of τc (M), but the quality of the orientation of the τc (M) phase The pressure direction is 35 ° in close relationship with the orientation of the ε'c (M) phase before transformation.

θ ₁

90 °, 0 °

θ ₂

In the angular range of 15 °, the ε'c phase of the matrix formed by the εc → ε'c transformation is generally unidirectional, followed by a unidirectional or bidirectional τc phase by the ε'c → τc transformation.

On the other hand, in the pressing directions of θ ₁ = 0 °, θ ₂ = negative and θ ₁ = 90 °, θ ₂ = 30 °, ε'c (M) phases in multiple directions are formed, thus τc (M) in multiple directions. It was evident by the X-ray diffraction that the image formed.

Therefore, in order to obtain anisotropic magnets having magnetic properties of BMmax = 6.0 × 10 ⁶ GOc or more, it was confirmed that it is important to form a unidirectional ε'c (M) phase in general.

θ ₁

90°, 0°

θ ₂

15°의 각도 범위내에 있는 가압방향에 있어서, 530∼830℃의 온도 범위내에서는 BHmax가 6×10⁶G·Oe 이상의 뛰어난 자기특성을 갖는 이등방성 자석이 되지만, 500℃이하의 온도에서는 가소성이 거의 없어서 이등방성화되지 않으며, 또 850℃이상의 온도에서도 가소성이 적어져서, 자기특성은 거의 등방성이었다.35 ° when changing the pressurization temperature

θ ₁

90 °, 0 °

θ ₂

In the pressing direction in the angle range of 15 °, in the temperature range of 530 to 830 ° C., the BHmax becomes an anisotropic magnet having excellent magnetic properties of 6 × 10 ⁶ G · Oe or more, but at a temperature of 500 ° C. or lower, Almost no, it was not anisotropic and less plasticity was achieved at temperatures above 850 ° C, and the magnetic properties were almost isotropic.

θ ₁

90°, 0°

θ ₂

15°인 각도 범위내에 있는 시료에서도, 실시예 1에서 전술한 바와같이 그 변형율 이 다음에 설명하는 포화변형율 이상으로 수축한 경우 및 포화변형율의 1할에 도달하지 않을 경우는 어느 것도 자기특성은 낮았다.Next, the relationship between the strain and the magnetic properties is examined.

θ ₁

90 °, 0 °

θ ₂

Even in a sample within an angle range of 15 °, as described above in Example 1, the magnetic properties were low both when the strain contracted above the saturation strain described below and when the strain did not reach 10% of the saturation strain. .

The saturation strain reaches saturation in the pressing direction when the ε e (M) single crystal becomes τ c (M) single crystal due to the ε c → ε'c → τ c transformation according to the atomic plane shift in the specific direction described in Example 1 The strain is theoretically calculated according to the transformation mechanism of Example 1.

Therefore, the saturation strain depends on the pressing direction.

For example, Fig. 6 shows the saturation strain when θ ₁ is changed at θ ₁ = 0 °.

It was confirmed by X-ray diffraction that the samples deformed above the saturation strain had an elongation also is isotropic, their magnetic properties and orientation lost, and both became τc (M) in the multi-direction.

Example 3

The manganese-aluminum-carbon alloy having a unidirectional? C (M) phase produced by the method of Example 1 and Example 2 was subjected to high temperature processing by changing the pressing direction.

In Example 2, sample S ₉ on unidirectional? C (M) produced by high temperature processing and annealing treatment was pressed under the same direction as the initial pressurization by applying a pressure of 40 kg / mm 2 at a temperature of 600 ° C.

As a result, since it was hardly deformed, it increased again by 80 kg / mm <2> and continued 8% contraction in the pressurization direction, and it extended dynamically in the direction orthogonal to a pressurization direction.

When the magnetic properties of the sample after pressurization were measured, the unidirectionality on τc (M) was broken down, and the magnetic characteristic in the magnetization upper direction before pressurization was significantly deteriorated to BMmax = 3.8 × 10 ⁶ G.Oe. .

Next, in Example 1, the sample after annealing of S _{3 made} of τc (M) single crystal was subjected to a pressure of 40 kg / mm 2 at a temperature of 560 ° C. in a direction parallel to the direction of magnetization upper right perpendicular to the initial pressing direction. When pressurized, the strain was hardly deformed. Thus, when the temperature was raised to 600 DEG C and pressurized, a rapid plastic strain reaching saturation similar to that of Fig. 3 was found.

The contraction rate in the pressing direction reached -27%, the elongation in the direction perpendicular to the pressing direction was as large as 28% in the direction parallel to the initial pressing direction, and about 1% in another perpendicular direction, so that a slight elongation was recognized. The orientation was recognized for elongation.

When the magnetic permeability of this sample was measured, the magnetization upper direction was greatly changed in the direction in which remarkable elongation occurred, that is, the direction substantially parallel to the initial pressing direction, and the magnetization in the magnetizing upper direction before pressing, that is, in the pressing direction. The characteristic was significantly reduced.

τc 변태의 가역성(可逆性)에 의한 것임이 밝혀졌다.In this way, when the τc (M) phase single crystal sample was pressed upward in the magnetization rain direction, a significant plastic deformation occurred, and the phenomenon in which the magnetization rain direction was greatly changed by X-ray diffraction or electron microscopy was examined. ε'c where atomic plane movement occurs in the direction of returning the atomic plane movement in a specific direction in the τc transformation to the opposite home position.

It turned out that it was due to the reversibility of τ c transformation.

That is, when the plate crystal on the τc (M) formed by the ε'c → τc transformation described in Example 1 is pressed in the magnetization upper direction, that is, the τc [001] direction, ε'c (100) // τc (111 Atomic planes parallel to the τc (111) plane in relation to) receive a stress in the τc [112] direction and move only a specific distance in that direction.

This atomic plane shift is a shift in the direction opposite to the transverse direction of the atomic plane parallel to the ε'c (100) plane in the ε'c → τc transformation, τc → ε corresponds to 'c metamorphosis.

In addition, the crystal orientation differs from the τc phase prior to pressurization by moving only a specific distance in the ε'c [001] direction of the atomic plane parallel to the (100) plane due to the τc → ε'c transformation. A new one-way τc phase is formed.

In addition, such atomic plane movement in the plane parallel to the τc (111) plane is recognized only in the atomic plane parallel to the τc (111) plane in relation to only ε, c (100) // τc (111), and the other plane. Movement was not recognized in the atomic plane parallel to the different τc [111] plane groups in the direction.

In addition, when the tissue after pressing was irradiated with an optical microscope, as described in Example 1, the layered Mn3AlC phase was a smooth and smooth structure except for a slip band or the like.

Magnetic properties in the magnetized rain direction on the newly formed τc (M)

Br = 6.850G BHc = 1.900Oe BHmax = 7.0 × 10 ⁶ G.Oe

It was.

Next, in Example 2, the sample of S ₁₅ having two different τ c [001] axes was pressed by applying a pressure of 35 kg / mm 2 at a temperature of 600 ° C. parallel to one τ c [001] axis. Rapid plastic changes to saturation, similar to 3 degrees, were found, resulting in stable orientation even at elongation.

X-ray diffraction of the sample after pressurization showed that the sample had an approximately unidirectional τc (M), and the τc [001] axial direction was different from the pressing direction before pressurization. It was confirmed that one τc [001] axis was switched to the other τc [001] axis by pressurization in parallel with the axial direction.

τc 변태의 가역성에 따른 것이라는 것이 밝혀졌다.Ε'c of the τc [001] axis also described above

It turns out that it is due to the reversibility of the τ c transformation.

The magnetization upper direction of the sample after processing is in the τc [001] axis direction.

Br = 6.800G BHc = 1.850Oe BHmax = 6.9 × 10 ⁶ G.Oe

As a result, Br was improved compared with the magnetic property in the magnetizing direction before processing.

Example 4

Chemical analysis values prepared in the same manner as in Comparative Example 1 were to cut cubes or cuboids of 5 to 12 mm on one side with various crystal planes from the εc-phase single crystals of 71.95% manganese, 26.95% aluminum and 1.10% carbon. The same experiment as in Example 1 and Example 2 was carried out with respect to each sample.

As a result, the results show qualitatively the same tendency as in Example 1 and Example 2, such as the relationship between the pressure direction and the deformation and the relationship between the pressure direction and the degree of anisotropy. X-ray diffraction was confirmed by the presence of ε'c phase.

However, as compared with the experimental results of the samples of Examples 1 and 2 in which Mn 3 AlC was deposited in layers, the experimental results of the εc phase samples without the layered Mn 3 AlC phase were small, so that the pressure required for deformation was also implemented. In the case of Example 1 and Example 2, 15-40 kg / mm <2> was enough, but in this case, the pressure of 35-60 kg / mm <2> which is many tens of% of it is needed, and also anisotropically magnetized Since the orientation of the τc phase was poor, it was anisotropic magnet having lower magnetic properties than in the case of Examples 1 and 2.

For example, a single crystal sample of the εc phase having the above-described composition was pressed under a pressure of 560 ° C. and a pressing force of 50 kg / mm _{2 under} a pressing direction of θ ₁ = 90 ° and θ ₂ = 0 °. -1.9%, which was virtually nonmagnetic in measuring magnetic properties.

X-ray diffraction was performed on the sample after pressurization in various directions, and only the diffraction lines on the ε'c phase had the ε'c [001] axis mainly in the pressing direction but were not single crystals.

In addition, when the state of the phase was observed with an optical microscope, the structure intersected approximately 10 crosses on the surface of the sample was recognized, and crystals of the ε'c phase with different crystal orientations were observed.

The sample after pressurization was subjected to an annealing treatment at 570 ° C. for 4 hours to obtain an anisotropic magnet having a magnetizing upper direction in the pressing direction.

Magnetic properties in the pressing direction

Br = 5450G BHc = 2200Oe BHmax = 3.8 × 10 ⁶ G.Oe

In a direction corresponding to the [1120] direction before pressing in a direction perpendicular to the pressing direction

Br = 1000G BHc = 600Oe BHmax = 0.2 × 10 ⁶ G.Oe

In another direction perpendicular to the pressing direction

Br = 2400G BHc = 1400Oe BHmax = 0.9 × 10 ⁶ G.Oe

It was.

This magnetic characteristic value is compared with the magnetic characteristic value in the same experiment as in Example 2, in this case, Br is about 2% in the magnetization right direction, BHmax is about half, and the degree of magnetization curve is also lowered and isotropic. The degree of degree of deterioration was lower than that of Example 2.

Further, even when the above-mentioned conditions of pressurization temperature, pressing force, strain, and annealing conditions after pressurization were changed, further improvement of the magnetic characteristics was not recognized.

In the case of various changes in the pressing direction, the magnetic properties of the samples were about 1 to 3 times lower than the magnetic properties in Example 2, and the BHmax was about half that of the layered Mn 3 AlC phase between Example 2 Intrinsic differences with and without were recognized.

The cause of the difference in magnetic properties in Examples 2 and 4 was investigated by optical microscopy and X-ray diffraction. In the case of Example 2, the layered Mn 3 AlC phase was ε'c in the matrix during high temperature processing. It is effective in suppressing the generation of the ε'c phase in the multi direction such as twins of the phase and increasing the orientation of the τc phase. Therefore, the orientation of the ε'c phase of the matrix after the annealing treatment is also superior to that in Example 4, and the magnetization direction is right. It has been found that the magnetic properties in are significantly improved than in the case of Example 4.

As described above, the Mn3AlC phase extracted in a layered manner by M treatment has the effect of facilitating atomic surface movement in the manganese-aluminum-carbon alloy and enabling high-temperature processing at low pressure, and also crystallization. There is an effect of increasing the orientation by regulating the formation direction of the.

Therefore, it has become clear that the presence of the layered Mn3AlC phase is extremely important in obtaining anisotropic magnets having extremely excellent magnetic properties with high anisotropy.

Comparative Example 3

In the chemical analysis, manganese-aluminum-based alloys having a composition of 71.81% manganese and 28.19% aluminum were tried to prepare the ε single crystal by the dissolution cooling method applying Comparative Example 1.

The obtained alloy was a polycrystalline body, and the residual of the ε phase was extremely small, most of which became the β- Mn phase and the r phase, which were at room temperature, and the τ phase was also recognized in part.

Also, various changes in the composition, dissolution conditions, and cooling conditions of manganese, aluminum, tend to be almost the same as described above, and significant cracking occurred when quenched in water at a high temperature of 900 ° C. or higher to obtain an ε phase.

On the other hand, the manganese-aluminum of the same composition as above heats the raw alloy at a temperature of 1100 to 1200 ° C for a week to promote recrystallization as ε phase, and the sample is immersed in water at this temperature so that the sample contains significant cracks. However, the ε phase of the particle diameter of about 3 to 5 mm was obtained.

From this polycrystalline body of ε phase, a relatively large grain was selected, and a 3 × 3 × 3 mm cube sample having a plane parallel to (3304), (1120), and (3308) was cut off, and this was θ ₁ = 55 ° and θ ₂ = In the pressing direction of 0 °, that is, in a direction perpendicular to the (3304) plane, pressing was performed under the conditions of a pressing temperature of 580 ° C. and a pressing force of 40 gk / mm 2 to give a strain of -14.7%.

After processing, the elongation is isotropic and the magnetic properties

Br = 1350G BHc = 650Oe BHmax = 0.2 × 10 ⁶ G.Oe

Was an isotropic magnet.

X-ray diffraction was performed on the sample after processing, and τ phase, β- Mn phase, and γ phase diffraction lines exist, and the τ phase was hardly recognized in orientation. Moreover, also when the pressurization temperature, the pressing force, and the strain rate were changed in various ways, the sample of only τ phase cannot be obtained by the same tendency as described above, and it was not anisotropic.

This manganese-case of an aluminum-based alloy, manganese-aluminum-because of the carbon-based alloy and is poor in stability over due to the difference ε-phase, and τ in more than 530 ℃ only, as well as difficult to present as phase τ, in particular by machining γ phase and a β It is thought that this is because the decomposition to the -Mn phase is promoted and the aroma control effect by the layered Mn3AlC phase described above is not provided.

Example 5

Composition ratios of manganese, aluminum, and carbon Manganese 67.0 to 74.0%, carbon 0.1 to 2.5%, and the manganese-aluminum-carbon alloys in the range of ε or εc (M) phases of the manganese-aluminum-carbon alloys, or polycrystalline large crystals Then, single crystal samples of ε or εc (M) were cut out from this, and pressurized at a pressure of 40 kg / mm ₂ at a temperature of 570 ° C. in a pressing direction of θ ₁ = 55 ° and θ ₂ = 0 °.

상 및β-Mn상이 추출되어 있어서 등방성이 낮은 자기특성이었다.Table 4 shows the magnetic properties in the magnetization superiority direction when the chemical analysis value and the annealing treatment were applied after pressing. Samples of S ₂₃ and S ₂₄ containing less than (1/10 Mn-6.6%) of dissolved carbon are hardly mobile-spun, and

Phases and β- Mn phases were extracted and had low magnetic isotropy.

The sample of S ₂₅ has a large amount of β- Mn phase, and the sample of S ₃₀ has a large amount of phase,

TABLE 4

The degree of anisotropy was also small and both were low magnetic properties. All samples of S ₃₁ , S ₃₂ , and S ₃₃ containing more than 1 / 3Mn-22.2% of carbon had Al ₄ C ₃ phase before processing, and the anisotropy degree was small after processing. It was a magnetic characteristic. In addition, all the samples of S ₃₁ , S ₃₂ , and S ₃₃ were found to have collapsed. For these samples having BHmax = 2.0 × 10 ⁶ G.Oe or less, the magnetic properties were lower than BHmax = 2.0 × 10 ⁶ G · Oe, even if the pressurization direction, pressurization temperature, strain rate, or flipping condition were changed. . In the above experimental results, the composition range having excellent magnetic properties of BHmax = 6.0 × 10 ⁶ G.Oe or more

Manganese 68.0-73.0%

Carbon (1 / 10Mn-6.6) to (1 / 3Mn 22.2%)

Aluminum rest

It turns out that it is limited to.

Example 6

Manganese 72%, aluminum 27% and carbon 1% were blended, dissolved at about 1400 ° C. for 20 minutes, and cast in a cooling mold.

The obtained cast product was manganese crystal 71.83%, aluminum 27.19%, carbon 0.98% by chemical analysis, and columnar crystals were observed in the first solidified portion under an optical microscope.

The cast was subjected to M treatment at 850 ° C. for 20 minutes and quenched at this temperature. As a result, extraction of layered Mn ₃ AlC in the columnar grains was confirmed, and the grains were formed at an angle close to the growth direction of the columnar grains. Many.

X-ray diffraction of this cast body confirmed diffraction lines of the εC phase and the layered Mn ₃ AlC phase.

A 6 × 6 × 6 mm cube sample having a face perpendicular to the growth direction of the columnar tablet was cut out from the cast body and pressed under a condition of a pressurization temperature of 650 ° C. and a pressing force of 45 kg / mm 2 in a direction perpendicular to the growth direction. . The strain of the sample in the pressing direction was -25.5%. Since the sample after pressurization was nonmagnetic, it was annealed at 570 degreeC for 4 hours, and the anisotropic magnet which has the magnetization superior direction in the direction orthogonal to a pressurization direction was obtained.

Magnetic properties in the pressing direction,

Br = 2,800G BHmax = 1.1 × 10 ⁶ G.Oe

BHC = 1,500Oe

In a direction perpendicular to the pressing direction, in a direction parallel to the growth direction of the columnar tablet before pressing

Br = 4,800G BHmax = 3.6 × 10 ⁶ G.Oe

BHC = 2,350Oe

In another direction perpendicular to the pressing direction,

Br = 4,750G BHmax = 4.0 × 10 ⁶ G.Oe

BHC = 2,400Oe

It was.

Example 7

×35mm의 원주상 시료를 각각 끊어내었다. 끊어낸 각기의 시료에 대하여 1150℃의 온도로 2시간 가열한 후 이 온도에서 830℃까지 10∼15℃/분의 냉각속도로 서냉하고, 다시 830℃에서 20분간 유지하는 M처리를 한후, 830℃에서 300∼3000℃/분의 냉각속도로 담금질하고, 다시 600℃로 1시간 풀림열처리를 하였다.By chemical analysis, the rod-shaped cast bodies of nine manganese-aluminum-carbon alloys of P ₁ to P ₉ having the composition ratios shown in Table 5 were produced by melt casting. Dissolution was maintained at about 1450 ° C. for 30 minutes to sufficiently dissolve carbon. 20mm from this

Cylindrical samples of 35 mm each were cut out. Each sample cut out was heated at a temperature of 1150 ° C. for 2 hours, and then slowly cooled to 830 ° C. at a cooling rate of 10 to 15 ° C./min, followed by an M treatment held at 830 ° C. for 20 minutes, and then 830 ° C. Quenching was carried out at a cooling rate of 300 to 3000 ° C./min at 300 ° C., followed by annealing heat treatment at 600 ° C. for 1 hour.

The samples after the heat treatment were examined by X-ray diffraction, optical microscope, and electron microscope. As a result, in the samples having a composition of P ₃ to P ₉ containing (1/10 Mn-6.6%) or more of carbon content, The layered Mn ₃ AlC phase was recognized but the carbon content of P ₁ to P ₂ below

TABLE 5

In the sample of the composition, the layered Mn ₃ AlC phase was not recognized at all. Further, in the sample of the composition of an amount of carbon (1 / 3Mn 22.2%) over P ₈ ~P ₉ is τC phase and a recognition layer Mn ₃ Extraction of Al ₄ C ₃ in addition to the AlC in the sample of the composition of P β ₃ -Mn In the sample having a composition of P ₇ , a large amount of γ phase was present.

Each of these samples was subjected to the following high temperature processing. The sample having the composition of P ₁ was pressed in the axial direction of the circumference at a pressing temperature of 680 ° C. and a pressing force of 50 kg / mm 2, and subjected to compression processing with a deformation rate of -25% in the pressing direction.

Many cracks were generated in the sample after processing. The magnetic properties are significantly lower than those before the pressure BHmax = 0.6 × 10 ⁶ G.Oe

Br = 1,700G BHC = 700Oe

BHmax = 0.3 × 10 ⁶ G.Oe

It was Touhou.

As a result of X-ray diffraction of this sample, a large amount of β-Mn phase and γ phase were recognized except that a small amount of τ phase was recognized, and the magnetic properties were further reduced even if annealing heat treatment was added to this sample. . A sample having a composition of P ₂ was pressed in the axial direction of the circumference at a pressurization temperature of 710 ° C. and a pressing force of 55 kg / mm 2, and processed with a strain rate of -50%. The sample after processing was pulverized and showed little magnetism even when the magnet was close to the mass.

As a result of the X-ray diffraction of the sample after this processing, the existence of the τ phase was not recognized at all, and only the γ phase and the β- Mn phase were recognized. This is considered to be accelerated in the decomposition from the τ phase to the γ phase and the β- Mn phase as in the case of P ₁ described above.

The sample having the composition of P ₃ was subjected to compression processing of -40% in the axial direction of the circumference at a pressurization temperature of 630 占 폚 and a pressing force of 50 kg / mm 2.

After the processing, the magnetization superior direction was recognized in the radial direction, but the magnetic properties in this direction

Br = 2600G BHmax = 1.0 × 10 ⁶ GOe

BHC = 1500Oe

The magnetic properties were not improved even by the additional annealing treatment. As a result of the X-ray diffraction after processing, a large amount of β- mn is recognized, which is considered to have not improved the characteristics.

A sample having a composition of P ₄ was subjected to extrusion at a processing rate of 65% at a temperature of 720 ° C. and a pressing force of 40 kg / mm 2 in the axial direction of the circumference. In addition, the processing rate in extrusion processing represents the rate of reduction of the cross-sectional area of the sample before and after processing.

The sample after processing is an excellent anisotropic magnet having the magnetizing superior direction in the extrusion direction, that is, the axial direction of the cylindrical sample.

Br = 6100G BHmax = 5.5 × 10 ⁶ G.Oe

BHc = 2200Oe

It was.

With respect to the sample after processing, in the X-ray diffraction and optical microscopy the bar, and τC the layered Mn ₃ AlC a review of the state, the streaks on the layer nearest Mn ₃ AlC in relatively parallel to the extrusion direction was recognized. A sample having a composition of P ₄ was subjected to compression processing at a strain rate of -53% at a pressurization temperature of 650 ° C and a pressing force of 45 kg / mm 2 in the axial direction of the circumference. The sample after processing is anisotropic magnet having magnetization superior direction in the radial direction.

Br = 4900G BHmax = 4.3 × 10 ⁶ G.Oe

BHc = 2600Oe

It was.

A sample having a composition of P ₅ was subjected to compression processing in the axial direction of the circumference at a pressurization temperature of 680 ° C., a pressing force of 45 kg / mm 2, and a strain rate of -65%. The sample after processing is anisotropic magnet having magnetization superior direction in the radial direction.

Br = 5050G BHmax = 4.6 × 10 ⁶ G.Oe

BHc = 2600Oe

It was.

A sample having a composition of P ₅ was subjected to an extrusion pressure of 65% with a pressing force of 40 kg / mm 2 at a temperature of 630 ° C. in the axial direction of the circumference. The sample after processing is anisotropic magnet with extrusion direction magnetization superior direction.

Br = 5850G BHmax = 5.7 × 10 ⁶ G.Oe

BHC = 2250Oe

It was.

When the sample having the composition of P ⁵ is changed in the circumferential direction of the circumference and the processing temperature is in the range of 500 ° C. to 850 ° C., the magnetic properties in the processing temperature and the magnetization superiority direction when extrusion processing with a processing rate of 50% is shown. Mark on 6. At a processing temperature of 500 ° C. or less, there was almost no firing as in the case of Example 2, so that extrusion was difficult, remarkable generation of cracks, and no anisotropy.

Moreover, even at the temperature exceeding 830 degreeC, baking reduced, the generation | occurrence | production of a crack came and was not isotropicized.

Excellent anisotropic magnets with a BHmax of 4.8 × 10 ⁶ G.Oe or more are obtained within a pressurizing temperature range of 530 to 830 ° C.

TABLE 6

A sample having a composition of P ₆ was subjected to an extrusion process with a machining rate of 31% by applying a pressing force of 40 kg / mm 2 at a temperature of 700 ° C. in the axial direction of the circumference. Magnetic properties in the extrusion direction of the sample after processing

Br = 4350G BHmax = 2.4 × 10 ⁶ G.Oe

BHC = 1600Oe

It was.

When the sample after this processing was subjected to pressing force of 25 kg / mm2 in the same direction at a temperature of 700 ° C. again and subjected to extrude processing at a processing rate of 25%, the magnetic properties in the extrusion direction were

Br = 5700G BHmax = 5.0 × 10 ⁶ G.Oe

BHC = 1950Oe

It was.

A sample having a composition of P ₇ was applied with an applied pressure of 45 kg / mm 2 at a temperature of 780 ° C. in the axial direction of the circumference, and subjected to extrusion processing with a processing rate of 50%. The sample after processing produced the crack surface substantially perpendicular to the extrusion direction. Magnetic properties are determined in the extrusion direction

Br = 2750G BHmax = 1.8 × 10 ⁶ G.Oe

BHc = 1700Oe

It was.

A sample having a composition of P ₈ was subjected to compression processing in the axial direction of the circumference at a pressurization temperature of 750 ° C., a pressing force of 50 kg / mm 2, and a strain rate of -76%. In the sample after the processing, cracks in the radial direction occurred in the outer peripheral portion. The magnetization superiority direction is the diameter direction of the sample

Br = 3800G BHmax = 2.1 × 10 ⁶ G.Oe

BHc = 1800Oe

It was.

Al ₄ C ₃ was extracted in this sample and began to disintegrate after several days.

A sample having a composition of P ₉ was subjected to compression processing at a circumferential axial direction at a pressurization temperature of 700 ° C., a pressing force of 55 kg / mm 2, and a strain rate of -35%. The magnetization superiority direction is the diameter direction of the sample

Br = 3400G BHmax = 1.9 × 10 ⁶ G.Oe

BHc = 170Oe

It was.

This sample started to disintegrate after several days of precipitation of Al ₄ C ₃ . As shown in the above example, the sample in the phase state of τc (M) has excellent plasticity in the temperature range of 530 to 830 ° C, and also has a high ratio of mobile spinning by high temperature firing, and thus has an extremely excellent magnetic property. Isotropic magnets were obtained.

On the other hand, in the case of a phase state in which the filling Mn ₃ AlC phase does not exist, or in a phase other than the τc phase, for example, Al ₄ C ₃ , β- Mn, or γ in the presence of a layered Mn ₃ AlC phase, the plasticity is poor. In addition, the anisotropy ratio was also small and the magnetic properties were low. Therefore, as conditions for obtaining a good anisotropic magnet, manganese 68.0, 73.0%, carbon (1 / 10Mn-6.6%) to (1 / 3Mn 22.2%), and the composition range of the remaining aluminum is also a requirement in this case. It is necessary to carry out high temperature baking of this composition range τc (M) phase in the temperature range of 530-830 degreeC. Especially, the outstanding magnetic property more than BHmax = 4.8x10 <^6> G.Oe by the extrusion process of 40-65% of processing rate. An anisotropic magnet with was obtained.

In addition, the mechanical strength after processing is remarkably improved, the tensile strength is 20 kg / mm 2, the elongation rate is 5%, the tensile strength is 30 kg / mm 2 or more, and the machinability is extremely good, and the normal lathe is processed in the magnetized state. The good workability of the degree which can make cutting etc. also easy was shown.

Example 8

In such a cast body having a composition of P ₅ in Example 7, a cylindrical sample of 20 mm × 35 mm was cut out and held at a temperature of 1000 ° C. for 5 hours, and then cooled to 835 ° C. at a cooling rate of 10 ° C./min, again. Quenching was performed at this temperature at a cooling rate of 300-3000 ° C./min. In addition, when the sample was kept at 500 ° C for 10 minutes, it was confirmed by X-ray diffraction and optical microscopic observation that about 70% of the phases were εc (M) and about 30% were εc (M).

This sample was subjected to an extrusion process with a processing rate of 40% by applying a pressing force of 40 kg / mm 2 at a temperature of 730 ° C. in the axial direction of the circumference.

Since the magnetic properties in the extrusion direction of the sample after processing were low and the presence of the ε'c phase was confirmed by the X-ray diffraction, the annealing treatment was further performed at 600 ° C. for 2 hours, and the magnetization superior direction was observed in the axial direction of the sample. An anisotropic magnet with extremely excellent magnetic properties was obtained.

Br = 6200G BHmax = 6.0 × 10 ⁶ G.Oe

BHC = 2300Oe

It was.

Moreover, the mechanical strength and machinability after this heat processing were extremely good, and showed the same or more as Example 7.

Example 9

In Example 7, a cylindrical sample of 20 mm x 35 mm was cut out of the same cast as in Example 7 having a composition of P ₅ , held at a temperature of 1150 ° C. for 2 hours, and then cooled slowly to 1000 ° C., at this temperature. Quenching was carried out at a cooling rate in the range of 300 to 3000 ° C / min.

The sample epsilon c phase after this quenching was extruded in the axial direction of the circumference at the pressure of 60 kg / mm <2> at the temperature of 730 degreeC, and 40% of the processing rate. The strain rate was slower than the strain rate in the extrusion process of the τc (M) phase sample of the same composition in Example 7, and the strainability was bad. X-ray diffraction was performed on the sample after processing, and it was εc phase and ε'c phase.

After annealing at 600 ° C for 2 hours and measuring the magnetic properties, the sample after processing was measured in the extrusion direction.

Br = 5200G BHmax = 4.8 × 10 ⁶ G.Oe

BHc = 1950Oe

It was an isotropic magnet having magnetic properties of and having a magnetization superior direction in the extrusion direction.

The mechanical strength and machinability of this sample were also extremely good, and showed the same or better than Example 7,8,10.

Example 10

In the same cast as Example 7 having the composition of P ₁ to P ₉ of Table 5 in Example 7, each of the 20 mm ø35 mm cylindrical samples was cut off and held at 1150 占 폚 for 2 hours. Slow cooling was performed at a cooling rate of 10 ° C./min to 830 ° C., followed by M treatment held at this temperature for 20 minutes, and then quenched at a cooling rate of 1000 ° C./min at this temperature. Each sample after the quenching treatment was examined by X-ray diffraction, optical microscope, and electron microscope, and found to have a composition of P ₃ to P ₉ containing not less than 1/10 Mη-6.6% of a solid solution of carbon. Although the layered Mn ₃ AlC phase was recognized in the sample, the layered Mn ₃ AlC phase was not recognized at all in the sample having a composition of P ₁ and P ₂ with less carbon content. In addition, extraction of Al ₄ C ₃ in addition to the εc phase and the layered Mn ₃ AlC phase was recognized in the samples having a composition of P ₈ and P _{9 which} contained a carbon amount exceeding (1 / 3Mn-22.2%).

In the sample having the composition of P ₃ , the β- Mn phase and the r phase of the sample having the composition of P ₇ were recognized in a large amount in addition to the εC phase and the layered Mn 3 AlC phase, respectively.

The sample having the composition of P ₁ is a small amount of ε phase and a large amount of τ phase and β -Mn phase, and in the sample having the composition of P ₂ , approximately the same amount of τ phase, β -Mn phase, and r phase are mixed, respectively. Not admitted at all. The samples after these heat treatments were subjected to the high temperature processing described below, respectively, and further subjected to an annealing treatment suitable for the respective samples.

A sample having a composition of P ₁ was subjected to extrusion at a processing rate of 40% by applying a pressure of 50 kg / mm 2 at a temperature of 630 ° C. in the axial direction of the circumference. The sample after processing was grind | pulverized into the lump of 0.5-2 mm, and did not leave a round shape.

The large ones of these chunks were cut into 1mm square pieces and then annealed at 500 ° C for 30 minutes, and the magnetic properties were measured.

Br = 1200G BHmax = 0.1 × 10 ⁶ G.Oe

BHc = 400Oe

It was.

As a result of the X-ray diffraction of this sample, almost all of the β- Mn phase and the r phase had little residual of the τ phase.

This is considered to promote the decomposition of the r-phase and the β- Mn phase from the ε phase and the τ phase by processing.

A sample having a composition of P ₂ was subjected to compression processing of -20% in deformation at a pressurization temperature of 780 ° C and a pressing force of 45 kg / mm ₂ in the axial direction of the circumference. The sample after processing was pulverized, leaving no original original shape at all.

As a result of X-ray diffraction of the sample after this processing, the existence of the τ phase could not be recognized at all, and only the r phase and the β- Mn phase were recognized. This is considered to be accelerated in the decomposition from the τ phase to the r phase and the β- Mn phase as in the case of P ₁ described above.

A sample having a composition of P ₃ was subjected to compression processing at a strain rate of -50% at a pressurization temperature of 580 ° C. and a pressing force of 40 kg / mm 2 in the axial direction of the circumference. In the sample after processing, a small amount of radial cracks were recognized in the outer circumferential portion, and slight magnetism appeared.

The sample was subjected to annealing at 570 ° C. for 3 hours and the magnetic properties were measured. As a result, the magnetization superior direction was recognized in the radial direction.

Br = 2580G BHmax = 1.3 × 10 ⁶ G.Oe

BHc = 1400Oe

It was only.

In the X-ray diffraction results of the sample after processing and after annealing, a large amount of β- Mn phase is recognized, and therefore, it is considered that the magnetic properties do not improve.

A sample having a composition of P ₄ was subjected to an extrusion process with a processing rate of 50% by applying a pressure of 40 kg / mm 2 at a temperature of 720 ° C. in the axial direction of the circumference. The magnetic properties of the sample after processing were not good, and the presence of the ε'c phase in addition to the Mn3AlC phase was recognized by the X-ray diffraction results.

The sample was subjected to annealing for 10 hours at 550 ° C. and the magnetic properties thereof were measured.

Br = 6400G BHmax = 6.2 × 10 ⁶ G.Oe

BHc = 2550Oe

An anisotropic magnet having excellent magnetic properties and having a magnetization superior direction in the extrusion direction was obtained.

The sample state was examined by X-ray diffraction and optical microscope observation. As a result, streaks of the filling Mn3AlC phase, which were τc phase and Mn3AlC phase and relatively parallel to the extrusion direction, were recognized.

A sample having a composition of P ₄ was subjected to compression processing at a strain rate of -45% at a pressurization temperature of 650 ° C. and a pressing force of 45 kg / mm 2 in the axial direction of the circumference. The sample after processing had a nonmagnetic ε'c phase, and was subjected to an annealing treatment at 600 ° C. for 3 hours, and the magnetic properties were measured. The sample was anisotropic magnet having a magnetizing superior direction in the radial direction.

Magnetic properties in the magnetization dominant direction

Br = 5300G BHmax = 4.7 × 10 ⁶ G.Oe

BHc = 2600Oe

It was.

A sample having a composition of P ₅ was extruded at a rate of 50% by applying a pressure of 45 kg / mm 2 at a temperature of 630 ° C. in the axial direction of the circumference. The sample after the processing was partially nonmagnetic and subjected to an annealing treatment at 550 ° C. for 20 hours. As a result, the sample was anisotropic magnet having a magnetization superior direction in the extrusion direction.

Magnetic properties in the extrusion direction,

πⅠ 10000=6800GBr = 6250G

πⅠ 10000 = 6800G

BHc = 2500Oe IHc = 2800Oe

πⅠ 10000=0.92BHmax = 6.3 × 10 ⁶ G.Oe Br /

πⅠ 10000 = 0.92

It was.

The sample having the composition of P ₅ was extruded at a processing rate of 40% by changing the processing temperature in the axial direction of the circumference in the range of 500 ° C to 850 ° C. Table 7 shows the magnetic properties in the extrusion direction when the processing temperature and post-treatment annealing are applied.

When the processing temperature is 500 ° C. or less, as in the case of Examples 2 and 7, there is almost no plasticity and it is difficult to extinguish.

Moreover, even at the temperature exceeding 830 degreeC, baking reduced and it was not anisotropic with crack generation.

In the temperature range of 530-830 degreeC, the outstanding anisotropic magnet of BHmax = 5.2 * 10 <^6> G.Oe or more was obtained at the processing rate less than the case of Example 7.

TABLE 7

A sample having a composition of P ₆ was subjected to extrusion at a machining rate of 31% with a pressure of 40 kg / mm 2 at 650 ° C. in the axial direction of the circumference. The sample after processing had a nonmagnetic ε'c phase and was subjected to an annealing treatment at 620 ° C. for 2 hours, resulting in an anisotropic magnet having a magnetizing superior direction in the extrusion direction.

The magnetic properties in that direction

Br = 6300G BHmax = 5.3 × 10 ⁶ G.Oe

BHc = 2150Oe

It was.

In the axial direction of the sample having a composition of P ₇ , a compression hole of -35% was deformed at a pressurization temperature of 800 ° C. and a pressing force of 45 kg / mm 2.

The sample after the processing was partially nonmagnetic and subjected to an annealing treatment at 550 ° C. for 12 hours, whereby the magnetic property in the radial direction was slightly larger, and the magnet was in the direction of magnetization superior in that direction.

Magnetic properties in the magnetization rain direction,

It was.

A sample having a composition of P ₈ was subjected to compression processing at a strain rate of -18% at a pressurization temperature of 730 ° C. and a pressing force of 50 kg / mm 2 in the axial direction of the circumference. The magnetic property of the sample after processing was not good, and after annealing at 570 ° C. for 6 hours, it became anisotropic magnet having magnetization upper direction in the radial direction.

As low as.

The sample also began to collapse after a few days.

A sample having a composition of P ₉ was subjected to extrusion at a machining rate of 31% with a pressure of 55 kg / mm 2 at 780 ° C. in the axial direction of the circumference.

The magnetic properties of the sample after processing were low and layered cracks perpendicular to the extrusion direction were generated.

After annealing at 600 ° C. for 4 hours, the sample was a moving anisotropic magnet having a magnetization dominant direction in the extrusion direction.

As low as.

The sample also began to collapse after several days.

In addition, the magnetic torque was measured by cutting a disk sample having a magnetization superior direction in a direction parallel to the disk surface in a sample having a magnetic property of BHmax = 6.0 × 10 ⁶ G.Oe or more as described in the Examples. The directional magnetic torque curve is shown.

When the magnetic torque values of these samples are converted into magnetic anisotropy constants, the values are within the range of (0.63 to 0.86) x 10 ⁷ erg / cm 3, and the magnetic anisotropy constant of τc single crystal in Example 1 is 1.07 × When the degree of anisotropy was expressed by the ratio of 10 ₇ erg / cm 3, all of these samples had a high degree of anisotropy of about 0.6 or more.

In particular, the sample having a magnetic property of BHmax = 6.3 × 10 ⁶ G.Oe by extrusion processing having a composition of P ₅ has an excellent orientation due to its magnetic anisotropy number of 0.86 × 10 ⁷ erg / cm 3, resulting in extremely high anisotropy degree. It was an anisotropic magnet having.

As indicated in the above examples, manganese-aluminum-carbon alloys having an εc (M) phase have excellent plasticity within a temperature range of 530 to 830 ° C, and have extremely excellent magnetic properties by high temperature baking and annealing after processing. An anisotropic magnet could be obtained.

In this case, compared with the magnetic properties of the sample with the τc (M) phase in Example 7, excellent magnetic properties equivalent to or equivalent to those of Example 7 at a processing rate of 20 to 30% less than those of Example 7 were obtained. Anisotropic magnets are used.

In addition, most of the phase states after processing of the εc (M) phase are the ε'c phase and the layered Mn ₃ AlC phase, and the orientation control effect by the layered Mn ₃ AlC phase and the appearance of the ε'c phase of the orientation due to high-temperature firing It is considered that only the annealing treatment is applied after the processing, and an excellent anisotropic magnet is obtained.

Therefore, as conditions for obtaining a good anisotropic magnet, manganese 68.0-73.0%, carbon (1 / 10Mn-6.6)% (1 / 3Mn-22.2)%, and remaining aluminum in the composition range is also a requirement. In addition, it is necessary to carry out warm baking of the εc (M) phase of this composition range in the temperature range of 530 to 830 ° C. In particular, extrusion processing with a processing rate of 30 to 50% is extremely superior to BHmax = 5.2 × 10 ⁶ G.Oe or more. Anisotropic magnets with magnetic properties were obtained.

Moreover, the mechanical strength and machinability after processing and further annealing were remarkably improved, and the same result as those of Examples 7-9 were reached.

In addition, magnetic torque was measured for samples having magnetic properties of BHmax × 4.8 × 10 ⁶ G.Oe or more obtained in Examples 7 to 10 above, and the values converted from magnetic anisotropy constants to 0.43 × 10 ^{7 were obtained.} When the anisotropy degree is expressed by the ratio of the magnetic anisotropy constant of 1.07 × 10 ⁷ erg / cm 3 of the τc single crystal in Example 1 above erg / cm 3 or more, all of these samples have high anisotropy of about 0.4 or more. Had.

[Comparative Example 4]

By chemical analysis, rod-shaped castings of manganese-aluminum alloys with a composition of 71.62% manganese and 28.38% aluminum were formed by melt casting, and a 20 mm ø35 mm columnar sample was cut out from the cast for 1 hour at a temperature of 1000 ° C. It was then quenched in water.

A large number of cracks were observed in the sample after quenching.

The phase state of the sample after quenching was examined by X-ray diffraction and found only ε phase.

The ε phase columnar sample was subjected to compression processing of -50% in the axial direction of the circumference at a pressurization temperature of 650 ° C and a pressing force of 45 kg / mm 2.

The sample after processing is isotropic,

It was a low magnetic property of.

X-ray diffraction of the sample after processing revealed that many β- Mn phases and r phases existed.

Next, the above-mentioned hardening treatment was applied to the manganese-aluminum-based alloy in the τ phase, and subjected to compression processing as described above. The sample after processing was isotropic,

It was a low magnetic property of.

In the X-ray diffraction results of the sample after processing, a large amount of β- Mn phase and r phase were recognized, and τ phase was few.

In addition, even if the composition and pressurization conditions of manganese and aluminum were changed, and the processing method was changed, the results were almost the same as those described above, and magnetic properties of BHmax = 1.0 × 10 ⁶ G.Oe or more could not be obtained.

Such manganese-aluminum alloys are not only more stable in ε and τ phases than the manganese-aluminum-carbon alloys containing more than the solid solution as in Comparative Example 3, but also τ and β by high temperature processing of 530 ° C or higher. Since the decomposition to the -Mn phase is promoted, it is almost impossible to exist as τ phase, and since there is no aroma control effect by the layered Mn ₃ AlC layer, it is not anisotropic and also lacks plasticity. It was difficult.

Example 11

The same experiment as in Examples 7 and 10 was carried out on the manganese-aluminum-carbon-X alloy to which the additive element X was added to the manganese-aluminum-carbon alloy.

As X, Nb was selected, and a chemical analysis showed that a 20 mm diameter × 35 mm cylindrical manganese-aluminum-carbon-Nb alloy having a composition of 71.47% manganese, 25.06% aluminum, 1.03% carbon and Nb2.44% Made by the same melting, casting heat treatment.

The phase state of this alloy was examined by X-ray diffraction and optical microscopy, indicating that τc (M) phase was the main agent.

This aging was subjected to compression processing with a strain rate of -65% in the axial direction of the circumference under a pressurization temperature of 680 ° C. and a pressing force of 45 kg / mm 2. Magnetic properties of the direction

BHmax was improved more than the magnetic properties in the experiments such as manganese-aluminum-carbon alloy in Example 7.

Next, manganese 68.0-73.0%

Carbon (1 / 10Mn-6.6) to (1 / 3Mn-22.2)%

Aluminum rest

A manganese-aluminum-carbon alloy in the phosphorus composition range is 100, and thus B, N, Ti, Pd, Bi, V, Ag, Fe, Mo, Ge, Nb, Co, Pb, Zn, S, Ce, Sm One or two or more of the additional elements X bonded to each element of was prepared in various manganese-aluminum-carbon-X alloys in which the amount was within 6 by weight, and the same experiment as in Example 7 and Example 10 was performed. Was done.

As a result, especially in the manganese-aluminum-carbon- (Mb + Mo) alloy which added 2.0 Nb and 0.5 Mo by weight ratio, BHmax improves by about 10 compared with Example 7 and Example 10, and B Manganese-aluminum-containing one or more additive elements of Ti, Fe, Mo, Ge, Co, and Nb in an amount range of 3 or less in a weight ratio of 100 manganese-aluminum-carbon alloys Also in the carbon-X alloy, the improvement of the magnetic characteristic was recognized.

In addition, in the manganese-aluminum-carbon-alloy in which Pb of 3.0 was added in the weight ratio, the magnetic properties were almost the same or slightly lower than those in Examples 7 and 10, but the plasticity was remarkably good. This trend was also recognized in zinc-added manganese-aluminum-carbon-zinc alloys.

τc의 상 변태, 특히 ε'c상의 비정상적으로 큰 비등방성의 소성에 의한 것으로, 이 비정상 소성현상은 변태소성 변형이라고 호칭한다. 또, 이 변태소성 변형을 이용한 고온소성가공에 의한 현저한 비등방성화는 실시예 1,2,3에서, 변형기구, 변태기구, 자기기구에 대하여 상술한 바와같이 상기의 상 변태에 따른 다음의 결정면As evident in the above embodiment, at 530-830 [deg.] C. of the manganese-aluminum-carbon based alloy of 68.0-73.0% manganese, (1 / 10Mn-6.6)%-(1 / 3Mn-22.2)% remaining aluminum. Abnormally large calcination in εc → ε'c induced by high temperature processing

The phase transformation of τc, in particular the abnormally large anisotropic firing of the ε'c phase, is referred to as metamorphic deformation. In addition, remarkable anisotropy by high temperature baking using this metamorphic deformation is as described above for the deformation mechanism, the transformation mechanism, and the magnetic mechanism in Examples 1, 2, and 3 as follows.

εc (0001) // ε'c (100) // τc (111)

In particular, it is due to the atomic plane shifting from the ε'c (100) plane to the [001] direction. Thus, by extracting the layered Mn ₃ AlC phase to the εc (0001) plane, the preferred atomic plane shift in the above crystal plane is achieved. First of all, the anisotropic degree can be remarkably increased by this aromatic regulation effect.

The mechanism for the polycrystalline body is difficult to quantitatively explain, but the phenomena in the above-described embodiments can be explained qualitatively by deformation mechanisms, transformation mechanisms, and magnetic mechanisms such as single crystals. That is, in the case of polycrystals, in addition to the anisotropy deformation in each crystal grain, deformation necessary for rotation and movement of grain boundaries is required. Therefore, in general, the processing rate is larger than that of single crystals, and the processing rate is 3.0 to 6.5%. As the magnetic properties are good and the degree of anisotropy is also polycrystalline, it becomes 3 to 40% smaller than in the case of single crystal, but the composition range, phase state, and processing temperature range in which the above-mentioned phenomenon occurs are all common factors. It was confirmed that it was.

In achieving the unexpectedly significant anisotropy according to the above-described deformation mechanisms, transformation mechanisms, and magnetic mechanisms, it has been clearly shown in the present embodiment that the presence and the state of the employed carbon are one of the important essential factors.

In addition, some of the examples have been subjected to an annealing treatment after high temperature baking, but the annealing treatment has no orientation effect.

Therefore, in the ternary composition of manganese-aluminum-carbon shown in FIG. 7, the composition region surrounded by the lines connecting the points ABCD, that is, 68.0-73.0% manganese and (1 / 10Mn-6.6)% or more Anisotropically by performing high temperature annealing using metamorphic deformation due to phase transformation at 530 to 830 ° C. in a manganese-aluminum-carbon alloy containing (1 / 3Mn-22.2)% or less of carbon and remainder as aluminum. The degree of anisotropy described above is obtained by extracting the Mn ₃ AlC phase or similar face-centered cubic phase into the (0001) plane of the high-temperature phase (hexagonal) in advance, at this time. Can be significantly increased.

It goes without saying that the layered Mn ₃ AlC phase can be used as a simple crystal rock crystal method.

Therefore, according to the present invention, anisotropic magnets are obtained at BHmax = (6.0 to 9.2) x 10 ⁶ G.Oe, and their mechanical strengths are 4 to 10 times higher than those of conventional isotropic manganese-aluminum-carbon magnets. It is large, rich in toughness, and even after being magnetized, it is possible to perform cutting operations such as ordinary lathe machining, and also has excellent industrial properties due to its excellent weather resistance, corrosion resistance, stability, and temperature characteristics.

According to the present invention, not only extrusion and compression processing but also all plastic processing such as drawing, drawing, rolling, die rolling, and mold swaging are applied. In addition, it is possible to provide an anisotropic magnet having a magnetizing superiority direction in a free shape, in a free shape, in connection with being capable of cutting after magnetization.

Claims (1)

An alloy of 68.0-73.0% by weight of manganese and (1 / 10Mn-6.6)-(1 / 3Mn-22.2)% by weight of carbon and the rest of aluminum, with the Mn ₃ AlC phase layered on the (0001) plane of the high temperature phase. A method for producing a manganese-aluminum-carbon alloy magnet characterized in that it is anisotropically formed by high temperature baking at a temperature of 530 to 830 캜 after precipitation.

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