JPS6213427B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an L1 ₂ type intermetallic compound material having strength, toughness, and ductility, and a method for producing the same. Many attempts have been made to apply the ultra-quenching method from the molten state to various alloys, and a new non-equilibrium phase, which is different from the equilibrium phase, has been discovered. Particularly when focusing on steel materials, amorphous alloy steel is made possible by ultra-rapid cooling from the molten state, which makes it possible to add toughness and strength to ultra-high carbon steel materials that are too brittle to be put to practical use through normal processing and heat treatment. This is noteworthy as a new non-equilibrium phase material obtained by this method. Fe
-X-C series (X is any one of Cr, Mo, W or a combination of two or more) amorphous alloy steel has a breaking stress of 350Kg/mm ² and a Witzkers hardness of 1100DPN.
It has higher strength and hardness than normal alloy steel,
It is a material with excellent mechanical properties that are both tough and sticky, and its surface has a metallic coating. Moreover, its production can be done instantly from the molten state, and no complicated processes are required. However, since amorphous alloy steel has an atomic structure in a molten state that is frozen and solidified to room temperature as a non-equilibrium phase, a high cooling rate is required for its formation.
Therefore, the maximum thickness of an amorphous alloy steel tape produced by centrifugal quenching or roll quenching to obtain a tape-like continuous body is approximately 30 μm, and it is extremely difficult to obtain a thickness greater than that. Ta. Furthermore, if the cooling conditions during production are poor, crystalline materials will be present, which will significantly reduce the toughness, which is one of the major characteristics of amorphous alloy steel. As described above, amorphous alloy steel has the disadvantage that its shape (thickness) is limited and its manufacturing conditions require strictness. Furthermore, in order to improve the dimensional accuracy (surface irregularities, thickness) of the obtained tape-shaped material, it is difficult to perform the usual cold rolling. Therefore, it has been difficult to apply amorphous alloy steel to products that require strict dimensional accuracy. Therefore, the present inventors investigated the development of a new non-equilibrium crystalline alloy material in order to solve the above problems without impairing the excellent characteristics of amorphous alloy steel. Recently, the usefulness of L1 ₂ has been attracting attention from various quarters.
The unique brittleness of the Ni ₃ Al type intermetallic compound has been improved by adding a small amount of boron. However, L1 type ₂ intermetallic compounds doped with boron etc.
Ni ₃ Al has low strength and cannot be used as a strength material. In addition, Ni-Al alloys with an Al content of 23% or less in atomic ratio (hereinafter abbreviated as at) can produce Ni ₃ Al without adding boron.
Although a sticky material in which Ni and Ni coexist is obtained, its strength is still low. In view of the above points, the present inventors attempted to add toughness, ductility, and strength to the above-mentioned L1 ₂ type intermetallic compound Ni ₃ Al, and further solved the problems encountered with the above-mentioned amorphous alloy steel. A new high-strength material was developed by solving various problems. That is, the present inventors conducted rapid cooling from a molten state on various alloys in which various elements were added to the Ni--Al system. As a result, Fe―Ni―Al―
C-based alloy satisfies all requirements for toughness, ductility, and strength.
We discovered that L1 is a new non-equilibrium crystalline material consisting of type ₂ intermetallic compounds. It has also been found that even if part or all of Ni is replaced with Mn, and even if various elements are added to the above alloy system, strength can be increased without impairing toughness. In addition, we were able to solve problems with sample thickness, forming conditions, sample dimensional accuracy, etc. that had been a problem with amorphous alloy steel. The details of the present invention will be explained below. According to the equilibrium phase diagram, the Ni-Al binary alloy has a weight ratio (hereinafter abbreviated as wt) of approximately 12 to 15 wt% at room temperature.
It is Ni ₃ Al in the range of Al content, Ni ₃ Al and Ni coexist in the range of about 4 to 12 wt% Al content, and Ni solid solution containing Al in the range of about 4 wt% Al content or less. As a result of examining this binary Ni-Al alloy using a rapid cooling method from a molten state, it was found that L1 ₂ type intermetallic compound Ni ₃ Al was formed in compositions with an Al content of 12 wt% or more, but it was too brittle to be used for practical use. It was not a material that could be obtained. On the other hand, a Ni-Al alloy with a composition of 4 to 12 wt% Al contains Ni ₃ Al
It has a structure in which Ni and Ni coexist, and although it has tenacity, its strength is only below the breaking stress of 50 kg/mm ² .
In addition, if the amount of Al is less than 4wt%, Ni ₃ Al cannot be obtained,
It was a face-centered cubic phase in which Al was dissolved in Ni. Therefore, the present inventors attempted to increase the strength of the sticky Ni--Al alloy having a composition range of 4 to 12 wt% Al by adding various elements. First, we focused on Fe, which forms a complete solid solution with Ni in a face-centered cubic structure and is cheaper than Ni, and rapidly cooled from a molten state an alloy in which part of the Ni was replaced with Fe. As a result, although it was possible to partially replace Ni with Fe, only a slight solid solution hardening of Fe was observed, and the breaking stress was only about 60 Kg/mm ² . In addition, the structure was one in which Ni solid solution and _L12 type intermetallic compound coexisted. Therefore, we investigated adding carbon interstitial elements to Fe-Ni-Al alloys to increase solid solution hardening. The solid solution hardening of interstitial elements is greater than that of substitutional elements, and the addition of interstitial elements is effective in increasing the strength. However, because the solid solubility limit of these elements is usually small,
Various compounds precipitate and impair the tenacity of the material. In other words, in normal manufacturing methods, Fe
- It is difficult to incorporate a large amount of carbon into a Ni-Al alloy as a solid solution, and it precipitates as carbides, making it brittle.
However, by rapidly cooling the material from the molten state, a large amount of carbon could be dissolved in solid solution to extend the solid solubility limit. As a result, the solid solution of a large amount of carbon was able to impart significant solid solution hardening. As described above, rapid cooling from the molten state causes a large amount of carbon to be dissolved in the Fe-Ni-Al alloy, resulting in loss of toughness and ductility in the Fe-Ni-Al-C alloy in a specific composition range. We succeeded in increasing the strength without any damage. We also found that the structure of the above material is almost a single phase of L1 ₂ type intermetallic compound. As described above, we have invented a new L1 ₂ type intermetallic compound material that has added tenacity, ductility, and strength. Next, the reasons for limiting the alloy composition of the present invention will be described. In the Fe-Ni-Al-C alloy of the present invention, Al
is an essential element for forming the _L12 type intermetallic compound, and its necessary composition range is 4 to 12 wt%. At 4wt% or less, Al is dissolved in the matrix and does not form an _L12 type intermetallic compound. In addition, when the content is 12 wt% or more, an L1 ₂ type intermetallic compound is formed, but it is extremely sticky and brittle. Therefore, a sticky L1 type ₂ intermetallic material is obtained only in the range of 4 to 12 wt% Al. The main effect of carbon is to increase strength through solid solution hardening, and the effective composition range for this effect is 0.2 to 2.6 wt% C content.
In the case of a C content of 2.6 wt% or more, it is difficult to prevent the precipitation of cementite Fe ₃ C even by rapid cooling from a molten state, and Fe ₃ C precipitates at grain boundaries etc., significantly impairing the toughness. On the other hand, at 0.2 wt% or less, solid solution hardening of carbon is hardly observed. In addition, other effects of carbon are to lower the melting point of the molten metal, reduce its viscosity, and enhance the rapid cooling effect of carbon from the molten state, but if it is less than 0.2wt%, this effect is not sufficient. , the effect of rapidly cooling the alloy is almost eliminated. Furthermore, as another effect, it stabilizes the face-centered cubic structure and facilitates the formation of L1 ₂ type intermetallic compounds, but this effect is insufficient when the amount is less than 0.2 wt%. As described above, an L1 ₂ type intermetallic compound having toughness and strength in a carbon content range of 0.2 to 2.6 wt% can be easily obtained by rapid cooling from a molten state. Next, in the Fe-Ni-Al-C alloy having 4 to 12 wt% Al and 0.2 to 2.6% C, L1 ₂ of the present invention
The amount of Ni from which the type intermetallic compound is obtained is in the composition range of 5 to 70 wt%. If it is less than 5wt%, carbides are likely to form, resulting in a significant loss of stickiness. On the other hand, when it is 70 wt% or more, the solid solubility of carbon decreases, forming Fe ₃ C and impairing its stickiness. Further, in each of the above composition ranges of Al, C, and Ni, the remainder is Fe. One of the effects of Fe is solid solution hardening due to substitutional solid solution. Another effect is to dissolve a large amount of carbon into the matrix. In other words, in Ni--Al--C alloys that do not contain Fe, carbon is excluded from the matrix and precipitated as Ni ₃ C or graphite at grain boundaries, significantly impairing the toughness of the alloy. Furthermore, replacing a portion of Ni with Fe is advantageous in reducing material costs. In this way, an alloy consisting of Al, C, and Ni in the above composition range with the remainder Fe can be rapidly cooled from a molten state to simultaneously exhibit toughness, ductility, and strength.
L1 is a new material consisting of type ₂ intermetallic compound. Furthermore, part or all of the Ni in the above alloy can be replaced with Mn. In a composition range in which the total amount of Ni and Mn is 5 to 70 wt%, an _L12 type intermetallic compound having the same structure and mechanical properties as the above-mentioned alloy system can be obtained. The above Fe-X-Al-C alloy (X is Ni or Mn
Any one or both of the following, the total amount of which is 5 to 70wt
%), when one or a combination of two or more of Cr, Mo, and W are added as additive elements, the total amount of the added elements is 7wt% or less.
It is possible to increase the strength of L1 type ₂ intermetallic compounds without compromising their toughness and ductility. Note that if the total amount is 7 wt% or more, precipitation of carbides becomes significant, and toughness and ductility are significantly impaired. Furthermore, it is also possible to partially replace the element X, which is one or a combination of two of Ni or Mn, with Co in a range of up to 45 wt%. Co amount is 45wt
% or more, the stickiness and ductility of the resulting L1 ₂ type intermetallic compound will be impaired. In addition, Ni or
X consisting of one or a combination of two Mn and Co
Regarding the elements, the total amount of the X element must be in the range of 5 to 70 wt%, and if it is outside this range, the stickiness and ductility of the L1 ₂ type intermetallic compound obtained will be impaired. In addition, even if at least one of Ta, Zr, Nb, Ti, and Si is included as an additive element in all of the above alloy systems in a total amount of 2 wt% or less, impurities such as those present in ordinary industrial materials may be present. B, P,
Even if small amounts of As, S, etc. are contained, this does not pose any problem in achieving the present invention. The material of the present invention comprising the above-mentioned component ranges has a structure having L1 type ₂ intermetallic compounds even after being rapidly cooled from the molten state, and has an interstitial element of carbon or Fe,
This is a new _L12 type intermetallic compound that has added strength without sacrificing toughness and ductility through solid solution hardening of substitutional elements such as Cr, Mo, W, and Co. Next, a method for manufacturing the L1 ₂ type intermetallic compound material of the present invention will be explained. As described above, an alloy having an adjusted composition is heated and melted in an atmosphere or in a vacuum, and after being melted, it is rapidly cooled from a liquid state. It should be noted that there is no problem in using ordinary industrial raw materials when preparing the above alloy, and there are no special restrictions on their purity or the like. Various conventional liquid quenching methods are available for quenching from a liquid state, but from the viewpoint of the shape of the quenched material obtained, single roll method using rotating metal rolls, multi-roll method, or It is preferable to use one of the centrifugal quenching methods. When the above-mentioned rapid cooling method is used, there is no problem in carrying out the present invention whether it is in the air, atmosphere, or vacuum. Further, when performing the various quenching methods described above, the alloy of the present invention does not require a high quenching rate unlike amorphous alloy steel, so it can be easily produced using relatively small equipment. Taking the single roll method as an example, when using rolls made of the same material and having the same diameter, the alloy of the present invention is approximately 1/5 to 1/1 that of manufacturing an amorphous alloy.
It can be formed at a rotation speed of 0. That is, while it is difficult to form a thick sample of 30 μm or more with amorphous alloy steel, the present invention can form a thick sample of 100 to 400 μm. Also, unlike amorphous alloy steel, which causes a mixture of crystalline phases and significantly impairs the tenacity of the alloy due to slight variations in cooling conditions, the material of the present invention is crystalline, so even slight variations in cooling conditions There is no problem in carrying out the present invention. These points are extremely advantageous features in terms of manufacturing. Furthermore, as another method for manufacturing the material of the present invention, it is also possible to directly inject the molten alloy into a liquid medium at room temperature, such as water, through a nozzle hole or the like.
The materials of the invention are obtained directly by the respective methods described above and do not require any special post-treatment steps. Moreover, the obtained quenching material has a silvery white metal color. The quenched material of the present invention is easier to process, such as cold rolling, than amorphous alloy steel, and the accuracy of the material thickness and surface roughness can be adjusted. The cross-sectional shape of the quenching material is 0.02 to 0.4 in diameter.
Approximately circular in mm, or 0.02 to 0.4 mm thick, 0.2 mm wide
Although a rectangular shape of ~40 mm is a desirable size for the device, there is no particular restriction on the shape and size when the device is scaled up. The length of the wire or plate-shaped quenching material can be arbitrarily selected. The material obtained by the above manufacturing method achieves the object of the present invention even in a rapidly cooled state.
No special post-processing process is required except when cold rolling is performed to improve dimensional accuracy. The above manufacturing method has a manufacturing speed of several hundred m/sec, making it possible to produce at high speed. Furthermore, it is possible to produce wires or plate-shaped tapes or tapes of L1 _{and 2} type intermetallic compounds, which were previously difficult to process. Materials such as powders are provided through extremely simple processes. The increased speed and simplicity of the process also bring about effects such as lower manufacturing costs and energy savings when manufacturing the material of the present invention. L1 ₂ of the present invention manufactured based on the above manufacturing method
An example of an intermetallic compound is Fe-20wt%Ni-8wt
A transmission electron micrograph (magnification: 16,500 times) and electron beam diffraction spots of a rapidly cooled alloy having a composition of %Al-2.0wt%C are shown in Figures 1 and 2, respectively. The structure of the alloy with the above composition made by the conventional manufacturing method is a mixed phase of carbide and ferrite, but the structure of the alloy according to the present invention is a structure having face-centered cubic regular lattice spots, as is clear from FIG. It's getting old.
In other words, the structure in Figure 1 is L1 ₂ type intermetallic compound Ni ₃ Al
It has the same regular lattice as (Fe, Ni) ₃ Al
It is. Furthermore, in FIG. 1, no precipitation of carbides or the like is observed either at the grain boundaries or within the grains, and all carbon is solidly dissolved in this ordered lattice phase. Although FIGS. 1 and 2 show an example of the present invention, the same applies to all compositions and alloys within the scope of the claims. In Figure 1, the grain size is approximately
Although the crystal grain size is 2.0 μm, there is no particular restriction on the crystal grain size of the L1 ₂ type intermetallic compound of the present invention. The L1 ₂ type intermetallic compound material of the present invention having the above structure has excellent mechanical properties as described below. Conventional L1 type ₂ intermetallic compound
Compared to Ni ₃ Al, which was brittle and non-ductile, the L1 type ₂ intermetallic material of the present invention has a thickness of 100 to 400 μm.
It is a material with high tenacity and ductility that allows complete tight bending even in samples with a plate-like cross section, and can be cold-rolled by more than 50%. Furthermore, the strength of the conventional L1 ₂ intermetallic compound Ni ₃ Al, which is made by adding B etc. to the conventional L1 ₂ type intermetallic compound Ni ₃ Al to add toughness and ductility, is approximately 20 Kg/mm ² in yield stress and approximately 80 Kg in breaking stress. / ^mm2 . In comparison, the L1 type ₂ intermetallic compound material of the present invention is a Fe-Ni-Al-C alloy with a yield stress of 95 to 175.
Kg/mm ² (breaking stress is also approximately the same value). It is a material with excellent strength. Its hardness is 350~650DPN. Note that the tensile elongation is 5 to 30%, with almost no work hardening. Such increases in strength and hardness are largely due to solid solution hardening of carbon or Fe dissolved in the face-centered cubic regular lattice. Furthermore, if one or a combination of two or more elements such as Cr, Mo, and W are added, the strength and hardness will further increase without impairing the tenacity and ductility as long as the total amount is 7wt% or less. The maximum yield stress and breaking stress reach approximately 170Kg/mm ² and the maximum hardness reaches approximately 680DPN. Also, Ti, Zr, Nb, Ta, Si
Even when one or a combination of two or more of the following elements are added, substantially the same effect as the above-mentioned additive elements can be obtained as long as the total amount is 2 wt% or less. Even when Co is added, strength and hardness can be improved without impairing tenacity and ductility as long as the amount of Co is 45 wt% or less and the total amount of one or both of Ni or Mn and Co is in the range of 5 to 70 wt%. The maximum yield stress and breaking stress are approximately 170Kg/
mm ² and maximum hardness of approximately 680DPN. As described above, the L1 ₂ type intermetallic compound material of the present invention has a structure with the same regular lattice structure as Ni ₃ Al, and its mechanical properties are tough and capable of complete tight bending and cold rolling. It is also highly ductile. The strength is
Fe, Co, Cr, Mo, W, Ti, Zr, Nb, Ta, Si,
By solid solution hardening such as C, the maximum yield stress and breaking stress are approximately 170Kg/
mm ² and a maximum hardness of approximately 680 DPN, it is an L1 ₂ type intermetallic compound material with excellent mechanical properties. Next, examples of the present invention will be described. Example 1 A Fe-X-Al-C (X is either Ni or Mn or both) alloy system was rapidly cooled from a liquid state using the one-roll quenching method shown in Figure 3, and approximately A continuous plate-shaped rapidly cooled material with a thickness of 100 μm, a width of 5 mm, and a length of 3000 mm was obtained. The roll diameter was 200 mm, the material was tool steel, the rotation speed was 1000 rpm, and the test was carried out in the atmosphere. An example of the composition of Fe-X-Al-C alloy and Fe-X-Al-C alloy with Co,
An example of a composition with added elements such as Cr, W, and Mo is shown in the table. The results of transmission electron microscopy and electron beam diffraction of these quenched materials were almost the same as those shown in Figures 1 and 2, and both compositions were L1 ₂ type intermetallic compounds. Also, the thickness of alloys of any composition is approximately 100 μm.
180° complete contact bending was possible with a thickness of . Its mechanical properties are shown in the table. There is no reason to limit the manufacturing method to the single-roll quenching method, and the manufacturing conditions, shape of the quenching material, etc. are not limited to those in this example. Furthermore, each composition shown in the table merely shows an example of the present invention, and within each composition range of the claims, the same compositions as above may be used.

【table】

The results shown in [Table] were obtained. Example 2 A Fe--X--Al--C (X is either Ni or Mn or both) alloy system was rapidly cooled using the apparatus shown in FIG. As shown in the figure, the liquid alloy was directly jetted into the cooling medium through a nozzle to obtain a continuous linear quenched wire with a diameter of 0.1 mm and a length of 3000 mm. In FIG. 4, the cooling medium is a supersaturated aqueous solution containing crushed ice.
Approximately 0.2 kg of molten alloy is poured through a transparent quartz nozzle.
It was ejected at a pressure of mm ² . The results of transmission electron microscopy and electron beam diffraction of the obtained quenched material were almost the same as those shown in FIGS. 1 and 2, and L1 ₂ type intermetallic compounds were formed in both compositions. In addition, the rapidly cooled material with a diameter of about 0.1 mm having any composition could be bent completely in close contact by 180 degrees, and its mechanical properties were almost the same as the values shown in the table. In addition, in this manufacturing method, the manufacturing conditions such as the type of cooling medium, the material of the nozzle, the ejection pressure, and the shape of the quenching material are not limited to those in this example. Furthermore, the compositions shown in the table are examples of the present invention, and results similar to those described above can be obtained with each composition in the claims. Example 3 The intermetallic compound material of the present invention obtained in Example 1 was cold rolled. The maximum reduction rate was approximately 90%.
The rolled sample could be bent completely in close contact by 180°, similar to the quenched material before rolling. In addition, the mechanical properties of the sample after rolling were approximately the same as those of the rapidly cooled material, with only slight hardening due to work hardening being observed. As one of the effects of cold rolling, the surface roughness of the rapidly cooled material (3 to 5 μm in the width direction and 2 to 4 μm in the length direction) can be smoothed to about 0.05 to 0.1 μm in both the width and length directions by rolling. Ta. In addition, the dimensional accuracy of the thickness of the rapidly cooled material can be adjusted to 0.05 to 0.1 by adjusting the rolling reduction rate.
We were able to achieve an accuracy of μm. As described above, the L1 ₂ type intermetallic compound of the present invention enables plastic working such as cold rolling, which was difficult with conventional Ni ₃ Al, and does not impair the toughness and mechanical properties of the rapidly cooled material. Post-processing can be performed without any need for post-processing. Example 4 The intermetallic compounds of the present invention obtained in Examples 1, 2, and 3 were tempered while being maintained at various temperatures.
As a result, even after tempering at 500°C for 1 hour, it remained a sticky material similar to the quenched material. Also, Cr, Mo, W
In the case of alloys containing the following elements, even after tempering at 600°C for 1 hour, the material remained as sticky as the rapidly cooled material. Furthermore, even after the above-mentioned tempering treatments were performed, the mechanical properties were almost the same as those of the quenched material and were not significantly impaired. Note that at temperatures above the above heat treatment temperature, the L1 ₂ type intermetallic compound undergoes phase decomposition and its tenacity is impaired. Therefore, the intermetallic compound material of the present invention is a material that does not become brittle at all when tempered at about 600° C. for 1 hour or less. Example 5 In particular, in the quenching materials of the present invention obtained in Examples 1 and 2, the Co content was 20 to 40 wt% and the C content was 0.2 to 0.2.
Fe with 1.6wt% and other components within the claimed range
The magnetic properties of Ni-Al-Co-C-based quenched materials were measured. These alloys had semi-hard magnetic properties.
For example, the present invention Fe-20wt%Ni-8wt%Al-0.8wt
As a result of aging the %C-30wt%Co alloy at 600℃ for 1 hour, its coercive force was 210Oe and the magnetic flux density was
It was 3.5KG.

[Brief explanation of the drawing]

Figure 1 shows the present invention Fe-20wt%Ni-8wt%Al-
Transmission electron micrograph (16500x) of intermetallic compound material with 2.0wt%C, Figure 2 is an electron diffraction image, Figure 3 is a block diagram showing the principle of the single roll method, Figure 4 is a diagram showing the molten metal as a cooling medium. FIG. 2 is a schematic diagram illustrating the principle of the direct injection method; 1... Nozzle, 2... Molten metal, 3... Quenching material, 4...
Roll, 5...Heating source, 6...Liquid cooling medium.

Claims (1)

[Claims] 1. In weight ratio, at least one of Ni and Mn is 5 to 70% in total, Al is 4 to 12%, and carbon is 0.2 to 2.6%.
A high-strength intermetallic compound material, which is an alloy consisting of % iron and the balance is iron, and is configured as an L1 ₂ type intermetallic compound. 2 In terms of weight ratio, the total amount of at least one of Ni and Mn is 5 to 70%, Al is 4 to 12%, and carbon is 0.2 to 2.6%.
%, at least one of Cr, Mo and W is 7% in total
The following is a high-strength intermetallic compound material characterized by being an alloy consisting of iron in the balance and being configured as an L1 ₂ type intermetallic compound. 3 At least one of Ni and Mn in weight ratio
45% or less Co and 5 to 70% in total, Al 4 to 12
%, carbon in 0.2 to 2.6%, and the balance being iron, and is a high-strength intermetallic compound material characterized by being configured as an L1 ₂ type intermetallic compound. 4 In terms of weight ratio, at least one of Ni and Mn is 5 to 70%, Al is 4 to 12%, carbon is 0.2 to 2.6%, Ti
and at least one of Zr, Nb, Ta, and Si in a total amount of 2
A high-strength intermetallic compound material characterized in that it is an alloy with the balance consisting of iron and is configured as an L1 ₂ type intermetallic compound. 5 In terms of weight ratio, the total amount of at least one of Ni and Mn is 5 to 70%, Al is 4 to 12%, and carbon is 0.2 to 2.6%.
%, the balance being iron, is poured onto the circumferential surface of a rotating body made of a member with good thermal conductivity.