JP6259978B2 - Ni-based intermetallic compound sintered body and method for producing the same - Google Patents

Description

The present invention relates to a sintered body containing a Ni (nickel) -based intermetallic compound, in particular, a sintered body containing a Ni ₃ (Si, Ti) intermetallic compound and a method for producing the same.

Conventionally, tool steels, cemented carbides and ceramics have been used for applications requiring wear resistance such as dies, cutting tools and bearings.
Many of these applications are expected to have wear resistance even at high temperatures.
For example, for molds and cutting tools, it is possible to select more preferable processing conditions such as an increase in processing speed by ensuring wear resistance at higher temperatures, and for bearings at higher rotational speeds and / or higher temperatures. Can be used.

However, when tool steel reaches a temperature higher than the tempering temperature of the quenching and tempering process that is performed to obtain high hardness, the hardened and tempered structure is decomposed and softened. It is difficult to maintain.
In addition, although WC (tungsten carbide) itself has high hardness even at high temperatures, the cemented carbide has a metal phase such as Co (cobalt) used as a binder for bonding WC particles to each other at high temperatures. Since it softens, it is difficult to maintain wear resistance at high temperatures.
On the other hand, since ceramics have high hardness even at high temperatures, they can maintain wear resistance even at high temperatures. However, ceramic materials are poor in ductility and toughness both at room temperature and at high temperatures, and cost is high, so that the usable applications are limited to a narrow range and are difficult to use in many applications.

Thus, Ni-based intermetallic compounds, particularly Ni ₃ (Si, Ti) intermetallic compounds, have attracted attention as materials that have wear resistance at high temperatures and can be used in a wide range of applications (Non-patent Document 1).
Ni ₃ (Si, Ti) has a high hardness at high temperatures as compared with general metal materials including tool steel and cemented carbide, and therefore has excellent wear resistance at high temperatures.
Ni ₃ (Si, Ti) has sufficient ductility and toughness at room temperature and high temperature.
For this reason, by using a material containing Ni ₃ (Si, Ti), high wear resistance can be obtained at a high temperature in a wide range of applications.

Metal Vol. 80 (2010) No. 7 p. 548-554

However, since a material containing a conventional Ni ₃ (Si, Ti) intermetallic compound is produced as a melted material, it is necessary to obtain a cast material by heating to a high temperature using arc melting or the like. For example, even if precision casting is performed, the desired shape cannot be obtained due to the effects of thermal shrinkage, and it is necessary to perform further processing such as cutting and cutting after casting. was there.
Furthermore, since the ingot produced by the melt casting method has a solidified structure, the entire crystal grain size is coarse, and the crystal grain shape and grain size are not uniform depending on the product site, resulting in variations in material strength, ductility, and toughness. There is also a problem that is likely to occur.

Therefore, the present invention provides a material containing a Ni ₃ (Si, Ti) intermetallic compound, having high wear resistance at high temperatures and having high dimensional accuracy (near net shape), and a method for producing the same. For the purpose.

Aspect 1 of the present invention is a main phase comprising nickel (Ni) of 75 at% to 85 at%, silicon (Si) of 8 at% to 13 at%, and titanium (Ti) of 3 at% to 13 at%. Te is a sintered crystal structure is characterized by having a Ni 3 _(Si, Ti) a main phase comprising an intermetallic compound is a L1 ₂ type.

  In the aspect 2 of the present invention, the main phase further contains boron (B), and the content of the boron (B) is 10 mass ppm to 1000 mass ppm with respect to the total mass of elements other than boron of the main phase. The sintered body according to aspect 1, wherein the sintered body is characterized.

  Aspect 3 of the present invention is a hard particle containing at least one selected from metal carbide, nitride, carbonitride, oxide and boride, and further comprising hard particles dispersed between the main phases. It is a sintered compact of the aspect 1 or 2-3 characterized by including.

  Aspect 4 of the present invention is characterized in that the hard particles are Ti compound hard particles containing at least one selected from carbides, nitrides, carbonitrides, oxides and borides of titanium (Ti). It is a sintered compact as described in aspect 3.

According to Aspect 5 of the present invention, the Ti compound hard particles are at least one selected from TiC particles, TiN particles, TiCN particles, TiO ₂ particles, and TiB ₂ particles. It is a ligation.

  In aspect 6 of the present invention, the main phase is tantalum (Ta): 0.5 at% to 8 at%, niobium (Nb): 0.5 at% to 4 at%, aluminum (Al): 0.5 at% to 8 at%. And at least one selected from chromium (Cr): 0.5 at% to 8 at%, molybdenum (Mo): 0.5 at% to 8 at%, and cobalt (Co): 0.5 at% to 4 at%. It is a sintered compact in any one of the aspects 1-5 characterized by these.

Aspect 7 of the present invention is a mixed powder or alloy powder containing 75 at% to 85 at% nickel (Ni), 8 at% to 13 at% silicon (Si), and 3 at% to 13 at% titanium (Ti). Preparing the powder preparation process,
While applying a pressure to the mixed powder or alloy powder, heating the mixed powder or alloy powder, the crystal structure is L1 ₂ type Ni 3 _(Si, Ti) sintering having a main phase comprising an intermetallic compound A sintering process to form a body;
A method for producing a nickel (Ni) -based intermetallic compound sintered body.

  Aspect 8 of the present invention further includes a step of mixing hard particles containing at least one selected from metal carbide, nitride, carbonitride, oxide and boride before the sintering step. It is a manufacturing method of aspect 7 characterized by these.

  Aspect 9 of the present invention is characterized in that the hard particles are Ti compound hard particles containing at least one selected from carbides, nitrides, carbonitrides, oxides and borides of titanium (Ti). It is a manufacturing method of aspect 8.

  Aspect 10 of the present invention includes tantalum (Ta): 0.5 at% to 8 at%, niobium (Nb): 0.5 at% to 4 at%, aluminum (Al): 0.5 at% to 8 at%, chromium (Cr). : At least one selected from 0.5 at% to 8 at%, molybdenum (Mo): 0.5 at% to 8 at%, and cobalt (Co): 0.5 at% to 4 at% It is a manufacturing method in any one of aspects 7-9.

Aspect 11 of the present invention includes a base material containing nickel (Ni) of 75 at% to 85 at%, silicon (Si) of 8 at% to 13 at%, and titanium (Ti) of 3 at% to 13 at%, a metal At least one selected from carbides, nitrides, carbonitrides, oxides and borides, and a melting step of obtaining a molten metal in which at least the base material is melted, and atomizing the molten metal, Metal carbide, nitride in a nickel-based alloy matrix comprising 75 at% to 85 at% nickel (Ni), 8 at% to 13 at% silicon (Si), and 3 at% to 13 at% titanium (Ti), An atomizing step for obtaining an atomized powder having at least one selected from carbonitrides, oxides and borides; and heating the atomized powder with pressure applied And 75at% ~85at% nickel (Ni), 8at% ~13at% of (Si), comprises a 3at% ~13at% of titanium (Ti), Ni ₃ a and crystal structure L1 ₂ type Titanium compound containing a main phase containing (Si, Ti) intermetallic compound and at least one selected from metal carbide, nitride, carbonitride, oxide and boride dispersed between the main phase And a step of obtaining a sintered body containing hard particles. A method for producing a nickel (Ni) -based intermetallic compound sintered body.

  Aspect 12 of the present invention is characterized in that the metal carbide, nitride, carbonitride, oxide and boride are at least selected from titanium (Ti) carbide, nitride, carbonitride, oxide and boride. The hard particles are Ti compound hard particles containing at least one selected from carbide, nitride, carbonitride, oxide and boride of titanium (Ti). It is a manufacturing method of aspect 11.

Sintered body according to the present invention is characterized in that it comprises a Ni 3 _(Si, Ti) intermetallic compound is and crystal structure and a predetermined amount of Ni and Ti and Si L1 ₂ type.
Thereby, the sintered body according to the present invention has high wear resistance at high temperatures and can easily obtain a shape (near net shape) close to the shape of the final product.
Moreover, the sintered body having such characteristics can be obtained by the manufacturing method according to the present invention.

FIG. 1A is a ternary state diagram (part) of Ni—Si—Ti, and FIG. 1B is a state diagram showing a cross section along a straight line b in FIG. FIG. 2 is a schematic side view showing a discharge plasma sintering apparatus 100 used for performing discharge plasma sintering. FIG. 3A shows the SEM observation result of the sample after sintering at a sintering temperature of 800 ° C., and FIG. 3B shows the SEM observation result of the sample after homogenization treatment at a sintering temperature of 800 ° C. FIG. 4 (a) is an X-ray diffraction (XRD) result of a sintered sample at a sintering temperature of 800 ° C., and FIG. 4 (b) is an X-ray diffraction of a sample after homogenization at a sintering temperature of 800 ° C. It is a result. FIG. 5A shows the SEM observation result of the sample after sintering at a sintering temperature of 900 ° C., and FIG. 5B shows the SEM observation result of the sample after homogenization treatment at a sintering temperature of 900 ° C. 6A is an X-ray diffraction result of a sample after sintering at a sintering temperature of 900 ° C., and FIG. 6B is an X-ray diffraction result of a sample after homogenization at a sintering temperature of 900 ° C. . FIG. 7 shows the bulk density measurement results. For comparison, the density of the melted material is shown by a dotted line in FIG. FIG. 8 shows a room temperature hardness test result. 9 shows SEM observation results after sintering (before homogenization treatment), FIG. 9A shows the metal structure of Example 1-3, FIG. 9B shows the metal structure of Example 1-2, FIG. 9C shows the metal structure of Example 1-1. 10 shows X-ray diffraction results after sintering (before homogenization treatment), FIG. 10 (a) shows the X-ray diffraction results of Example 1-3, and FIG. 10 (b) shows Example 1-. 2 shows the X-ray diffraction result of FIG. 10, and FIG. 10C shows the X-ray diffraction result of Example 1-1. FIG. 11 shows SEM observation results after homogenization at 900 ° C. for 120 hours, FIG. 11 (a) shows the metal structure of Example 1-3, and FIG. 11 (b) shows the metal structure of Example 1-2. FIG. 11C shows the metal structure of Example 1-1. FIG. 12 shows the X-ray diffraction results after the homogenization treatment at 900 ° C. × 120 hours, FIG. 12 (a) shows the X-ray diffraction results of Example 1-3, and FIG. 12 (b) shows Example 1 -2 shows the X-ray diffraction result, and FIG. 12 (c) shows the X-ray diffraction result of Example 1-1. FIG. 13 shows SEM observation results after homogenization at 1050 ° C. for 48 hours, FIG. 13 (a) shows the metal structure of Example 1-3, and FIG. 13 (b) shows the metal structure of Example 1-2. FIG. 13C shows the metal structure of Example 1-1. FIG. 14 shows X-ray diffraction results after homogenization at 1050 ° C. × 48 hours, FIG. 14 (a) shows the X-ray diffraction results of Example 1-3, and FIG. 14 (b) shows Example 1 -2 shows the X-ray diffraction result, and FIG. 14 (c) shows the X-ray diffraction result of Example 1-1. FIG. 15 is a graph showing the bulk density after sintering of the samples of Examples 1-1 to 1-3 and after a homogenization treatment at 1050 ° C. × 48 hours. FIG. 16 is a graph showing the particle size distribution measurement results of the atomized powder obtained. FIG. 17 is an X-ray diffraction result of atomized powder. 18A shows the metal structure observation result of the sample after the homogenization treatment at a sintering temperature of 900 ° C., and FIG. 18B shows the metal structure observation result of the sample after the homogenization treatment at a sintering temperature of 1000 ° C. FIG. 19 is a graph showing the density measurement results. FIG. 20 (a) shows the average crystal grain size measurement result of Example 1-3 sample, FIG. 20 (b) shows the average crystal grain size measurement result of Example 1-2 sample, and FIG. The average crystal grain size measurement result of the sample of Example 1-1 is shown, and FIG. 20D shows the average crystal grain size measurement result of the sample of Example 2. FIG. 21 is a graph showing the results of room temperature hardness test. FIG. 22 is a graph showing the high temperature hardness test results. FIG. 23 is a graph showing the results of a tensile test. FIG. 24A shows the SEM observation result of the tensile test fracture surface of Example 1-3 sample, and FIG. 24B shows the SEM observation result of the tensile test fracture surface of Example 1-2 sample. FIG. 25A shows the metal structure observation result of the sample after the homogenization treatment at a sintering temperature of 900 ° C., and FIG. 25B shows the metal structure observation result of the sample after the homogenization treatment at a sintering temperature of 1000 ° C. FIG. 26A shows the X-ray diffraction result of the sample after the homogenization treatment at a sintering temperature of 900 ° C., and FIG. 26B shows the X-ray diffraction result of the sample after the homogenization treatment at a sintering temperature of 1000 ° C. FIG. 27 is a graph showing the bulk density measurement results after sintering and after homogenization treatment. FIG. 28 is a graph showing room temperature hardness after sintering and after homogenization treatment. FIG. 29 (a) shows the metal structure observation result after homogenization treatment of the sample of Example 4-1 and FIG. 29 (b) shows the metal structure observation result after homogenization treatment of the sample of Example 4-2. FIG. 29C shows the metal structure observation result after homogenization processing of the Example 4-3 sample, and FIG. 29D shows the metal structure observation result after homogenization processing of the Example 4-4 sample. FIG. 30 is a result of observation at high magnification of the metal structure of the same part of the same sample as FIG. 29, FIG. 30 (a) is a sample of Example 4-1 and FIG. 30 (b) is a sample of Example 4-2. 30 (c) shows the results of Example 4-3 sample, and FIG. 30 (d) shows the results of Example 4-4 sample. Fig. 31 (a) shows the X-ray diffraction result of the sample of Example 4-1, Fig. 31 (b) shows the X-ray diffraction result of the sample of Example 4-2, and Fig. 31 (c) shows the result of Example 4-. The X-ray diffraction results of three samples are shown, and FIG. 31 (d) shows the X-ray diffraction results of the sample of Example 4-4. FIG. 32 is a graph showing the room temperature hardness of Examples 4-0 to 4-4, in which the horizontal axis represents the volume ratio of TiC particles. FIG. 33 is a graph showing the high temperature hardness of Examples 4-0, 4-1, and 4-3. FIG. 34 is a graph showing the measurement results and theoretical values of bulk density of Examples 4-0 to 4-4. FIG. 35 is a photograph showing voids observed in the metallographic observation of the Example 4-4 sample, and voids are observed in the circled portions. FIG. 36 (a) shows the metal structure observation results of Example 4-5 sample by SEM, and FIG. 36 (b) shows the result of Example 4-5 sample by SEM at a higher magnification than FIG. 36 (a). It is a metal structure observation result. FIG. 37 is a graph showing the results of room temperature hardness test after homogenization processing of samples 5-0 to 5-4, and the horizontal axis is the volume ratio of TiB ₂ particles. FIG. 38 shows Example 5-0 (0% TiB ₂ ), Example 5-1 (10% TiB ₂ ) and Example 5-3 sample (30% TiB ₂ ) after homogenization and for comparison. It is a graph which shows the high temperature hardness of WC-Co which has the abrasion resistance in the highest level as the practical material used. FIG. 39 is an X-ray diffraction result of the sample of Example 5-5 after the homogenization treatment. FIG. 40 (a) is a metal structure observation result of the sample of Example 5-3 after the homogenization treatment, FIG. 40 (b) is an enlarged photograph of FIG. 40 (a), and FIG. 40 (c) is homogenization. It is a metal-structure observation result of Example 5-5 sample after a process, FIG.40 (d) is an enlarged photograph of FIG.40 (c).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, terms indicating specific directions and positions (for example, “up”, “down”, “left”, “right” and other terms including those terms) are used as necessary. These terms are used for easy understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meaning of these terms. Moreover, the part of the same code | symbol which appears in several drawing shows the same part or member.

As a result of diligent study, the inventors of the present application, as will be described in detail later, a sintering method (powder metallurgy method), more specifically, sintering using a powder having a predetermined composition and sintering under pressure law by using, 75 at% and ～85At% of Ni, 8at% ~13at% of Si and, 3at% ~13at% of Ti and the comprise becomes and the crystal structure is the L1 ₂ type _Ni 3 (Si, It was found that a sintered body having a main phase containing Ti) an intermetallic compound can be obtained.
In general, when trying to obtain a sintered body containing a plurality of components, particularly three or more elements (metal elements), a brittle intermediate phase often appears in addition to the target phase. For example, Ni ₃ ( Si, Ti) Even if an ordered crystal structure such as an intermetallic compound can be formed by sintering, it is difficult to obtain a desired wear resistance (hardness) due to the intermediate phase present at the same time. Has been considered.
However, the inventors of the present application do not form an intermediate phase (harmful intermediate phase) that significantly reduces the hardness by sintering under pressure, but without forming a Ni ₃ (Si, Ti) intermetallic compound. It has been found for the first time that a sintered body having desired wear resistance can be obtained. And, in one preferred embodiment, substantially _Ni 3 (Si, Ti) consisting only the intermetallic compound _(Ni 3 _(Si, Ti) intermetallic compound single-phase) and the sintered body is obtained Was also found for the first time.
That is, it has been found that by using such a sintering method, a material containing a Ni ₃ (Si, Ti) intermetallic compound can be obtained in a near net shape without obtaining a cast material.
This will be described below as a first embodiment.

Further, the inventors of the present application provide particles (hard particles) containing at least one selected from metal carbide, nitride, carbonitride, oxide and boride between main phases (between main phases), Preferably, the hardness at high temperature is further improved by dispersing particles containing at least one selected from Ti carbide, nitride, carbonitride, oxide and boride (Ti compound hard particles). Further, it has been found that a composite material having further excellent wear resistance can be obtained.
It has also been found that some sintered bodies in which Ti compound hard particles are dispersed have excellent wear resistance even at room temperature.
This will be described below as a second embodiment.

  The sintered body and the manufacturing method thereof according to Embodiments 1 and 2 of the present invention will be described in detail below, but before that, the meaning of some terms used in this specification will be clarified.

The term “main phase” is literally the main phase, usually the most abundant phase. More specifically, for example, in the observation of a cross-sectional structure having a visual field of 100 μm × 100 μm or more, it was obtained by image analysis or the like. The area ratio is 50% or more.
However, in Embodiment 2, which will be described in detail later, the hard particles (for example, Ti compound hard particles) intentionally dispersed for the purpose of improving the hardness may be larger in volume ratio (or area ratio) than the main phase. Good. Considering this case, the main phase may be present in an area ratio of 30% or more.

Further, one of the reasons for using the term “main phase” is that in Embodiment 2, metal carbide, nitride, carbonitride, oxidation, which is intentionally dispersed for the purpose of improving hardness (improving wear resistance). Particles containing at least one selected from the group consisting of oxides and borides (particles containing at least one selected from metal carbides, nitrides, carbonitrides, oxides and borides are sometimes referred to as “hard particles”) A portion comprising 75 at% to 85 at% Ni, 8 at% to 13 at% Si, and 3 at% to 13 at% Ti formed so as to include a Ni ₃ (Si, Ti) intermetallic compound ( Matrix).
For this reason, the “main phase” may collectively refer to portions other than the hard particles. The “main phase” has a composition of 75 at% to 85 at% Ni, 8 at% to 13 at% Si, 3 at% to 13 at% Ti, and Ni ₃ (Si, Ti) as long as it contains an intermetallic compound. For example, as shown in the examples described later, a plurality of phases (Ni ₃ (Si, Ti) intermetallic compounds such as Ni ₃ (Si, Ti) intermetallic compounds and other Ni ₁₆ Ti ₆ Si ₇ compounds). And other phases).

“The main phase contains Ni ₃ (Si, Ti) intermetallic compound” means normal X-ray diffraction (XRD), that is, normal measurement conditions without using a special X-ray source such as synchrotron radiation. , It means that it contains an amount sufficient to confirm the diffraction peak due to the L1 ₂ structure of the Ni ₃ (Si, Ti) intermetallic compound. Usually, this condition is surely satisfied if the volume ratio is 5% or more with respect to the entire main phase.

Ni ₃ (Si, Ti) intermetallic compound is an intermetallic compound having an L1 ₂ type crystal structure. This is an intermetallic compound in which part of Si of Ni ₃ Si, which is well known as an L12 type ₂ intermetallic compound, is substituted with Ti. In the case of "intermetallic compound _Ni 3 (Si, Ti)", as used herein, as long as it has an L1 ₂ type crystal structure, the ratio of the amount of Ni in the atomic ratio, the total amount of Si and Ti 3 It may have a composition deviating from the stoichiometric composition, as well as in a stoichiometric composition that is one.

Next, the term “Ni group (nickel group)” means that the amount of Ni is the largest among the contained elements, and preferably contains Ni of 50% or more in atomic ratio (at%). More preferably, Ni is contained in an atomic ratio (at%) of 60% or more.
Hereinafter, embodiments of the present invention will be described in detail.

A. Embodiment 1
1. Powder for sintering
(1) Form of sintering powder As described above, the present invention is characterized by using a sintering method in which sintering is performed under pressure. Therefore, a predetermined composition is used before sintering. The powder for sintering which has is produced.
The sintering powder may be, for example, Ni powder, Si powder, Ti powder, mixed powder obtained by mixing element powders such as Ta powder and B powder as necessary, and mixing them. These raw material powders may contain alloy powders in which a single powder contains two or more kinds of elements as long as the composition is within the predetermined range according to the present invention.
Moreover, the alloy powder obtained by atomizing the molten metal (molten alloy) which has a predetermined composition may be sufficient. Further, it may be a mixed powder obtained by mixing element powder and alloy powder.
When producing atomized powder, as a preferable condition, a molten metal melted at 1400 to 1800 ° C. in an inert gas atmosphere is dropped, and an inert gas can be sprayed thereto at a pressure of 30 to 100 kg / cm ² .

Among these, elemental powder is preferable. This is because the compounding composition can be easily changed by using the element powder, and the trouble of producing the atomized powder can be omitted, which is advantageous for cost reduction.
In addition, the particle diameter of the powder for sintering may have arbitrary particle diameters.
However, the particle diameter of the powder is preferably 1 to 150 μm. This is because if the particle diameter is larger than 150 μm, it is necessary to increase the sintering temperature in some cases in order to prevent the density of the sintered body from being lowered. In addition, if the particle diameter of the powder is smaller than 1 μm, the oxidation of the powder proceeds excessively, which may cause an adverse effect on the sintered body such as generation of oxides.
For mixing the raw material powder when obtaining the mixed powder, any method used in the technical field such as a mortar and pestle may be used, but the mixing is preferably performed using a ball mill. The reason why the ball mill is preferable is that the raw material powder can be dispersed and mixed more uniformly.
An example of suitable mixing conditions using a ball mill is wet mixing using a liquid such as alcohol.

(2) Composition of powder for sintering The composition of the powder for sintering is substantially equal to the composition of the main phase after heat treatment, which is appropriately performed after sintering or after sintering as will be described in detail later.
That is, to define the composition of the sintering powder here is to define the composition of the main phase of the sintered body.
Therefore, the composition of the sintering powder (main phase) is comprised of 75 at% to 85 at% Ni, 8 at% to 13 at% Si, and 3 at% to 13 at% Ti, and the balance consists of inevitable impurities. May be.

In addition, any element other than Ni, Si and Ti may be intentionally added to the sintering powder (that is, the main phase).
Examples of such elements include B (boron), Ta (tantalum), Nb (niobium), Al (aluminum), Cr (chromium), Mo (molybdenum), and Co (cobalt).
B has an effect of suppressing grain boundary fracture. The effect is limited if it is less than 10 mass ppm (mass ppm) with respect to the total mass of elements other than B (total content expressed by mass), and exceeds 1000 mass ppm with respect to the total mass of elements other than B. And B compound (boride) may be formed to cause embrittlement. Accordingly, a range of 10 to 1000 mass ppm with respect to the total mass of elements other than B (total content indicated by mass) (that is, the total mass of elements other than B: mass of B = 1: 0.00001 to 1: 0.001) is preferred.
Ta is an element effective for solid solution strengthening (hardening). The effect is limited when the Ta content is less than 0.5 at%, and when it exceeds 8 at%, the effect of improving the hardness is saturated, and an intermetallic compound phase such as Ni ₃ Ta is contained in the main phase. The problem of appearing more may occur. Therefore, the content of Ta is preferably 0.5 at% to 8 at%.
Nb is an element effective for strengthening solid solution (curing) and improving oxidation resistance. The effect is limited when the Nb content is less than 0.5 at%, and when it exceeds 4 at%, the effect of improving the strength is saturated, and the intermetallic compound phase such as Ni ₃ Nb is more contained in the main phase. There may be a problem that many appear. Therefore, the Nb content is preferably 0.5 at% to 4 at%.
Al is also an effective element for solid solution strengthening (hardening) and oxidation resistance improvement. The effect is limited when the Al content is less than 0.5 at%, and when it exceeds 8 at%, there may be a problem that ductility is lowered. Therefore, the content of Al is preferably 0.5 at% to 8 at%.
Cr is an element effective for improving high-temperature ductility and oxidation resistance. The effect is limited when the Cr content is less than 0.5 at%. The upper limit of Cr addition is not particularly specified, but if it exceeds approximately 8 at%, it is considered that the effect of improving ductility and oxidation resistance is saturated. Therefore, the Cr content is preferably 0.5 at% to 8 at%.
Mo is an element effective for improving the strength. The effect is limited when the Mo content is less than 0.5 at%. When the Mo content exceeds 8 at%, the effect of improving the strength is saturated, and an intermetallic compound phase such as Ni ₄ Mo is more contained in the main phase. There may be a problem that many appear. Therefore, the Mo content is preferably 0.5 at% to 8 at%.
Co is an element effective for improving strength and ductility. The effect is limited when the Co content is less than 0.5 at%. Although the upper limit value of the addition amount of Co is not particularly specified, it is considered that the effect of improving the strength and ductility is saturated when it exceeds approximately 4 at%. Therefore, the Co content is 0.5 at% to 4 at%. preferable.

-Preferred composition of powder for sintering 1
One of the preferable composition ranges includes Ni: 75.5 to 82 at%, Si: 10 to 13 at%, and Ti: 9 to 11 at%.
The reason why this composition is preferable will be described.
FIG. 1A is a ternary state diagram (part) of Ni—Si—Ti, and FIG. 1B is a state diagram showing a cross section along a straight line b in FIG.
If Ni: 75.5 to 82 at%, Si: 10 to 13 at%, Ti: 9 to 11 at%, the L1 ₂ single phase or most of the L1 ₂ phase is obtained, and normal temperature ductility, high temperature strength, high temperature hardness are obtained. Desirable characteristics can be obtained from the viewpoint.
The balance may be only inevitable impurities, and an arbitrary element such as B may be added. When adding B, you may contain B in the range of 10-1000 mass ppm with respect to the total mass (total content shown by mass) of elements other than B.
Moreover, 1 or more types selected from Ta, Nb, Al, Cr, Mo, and Co mentioned above may be included (the preferable range of content is also as above-mentioned).

  Moreover, in one preferable embodiment, the ratio of the Si content and the Ti content is an atomic ratio, and Si: Ti = 11.0: 9.2 to 9.7. As a result, it is possible to realize both high-temperature ductility and high-temperature strength.

-Preferred composition of powder for sintering 2
One of the preferable composition ranges includes Ni: 76.5 to 82 at%, Si: 10 to 13 at%, Ti: 4 to 11 at%, and Ta: 0.5 to 7.5 at%.
The reason why this composition is preferable will be described.
This composition is a composition in which a part of Ni or Ti is replaced with Ta in the above composition. L1 ₂ crystal structure _Ni 3 (Si, Ti) phase pronounced solution hardening when subtracting the Ni or Ti addition of Ta are expressed. When the same amount of Ta is added, the degree of hardening is greater when Ni is added and Ta is added than when Ti is added, but the degree of ductility reduction is also greater. On the other hand, when Ta is added by reducing Ti, more Ta can be added compared to the case of adding by reducing Ni, and as a result, the amount of Ti in the alloy is reduced, resulting in oxidation resistance. There is an advantage that can be improved. In the case where Ni is added in a reduced amount, the hardness value is saturated with Ta addition of about 2 at% or more. On the other hand, when Ti is added in a reduced amount, the hardness is saturated when Ta is added at about 7.5 at% or more. In either case, excess Ta addition leads to the appearance of the metallic phase other than L1 ₂ phase, impair the chemical properties such as mechanical properties and corrosion resistance and oxidation resistance, such as strength and ductility occurs.
Therefore, the effect of adding Ta described above can be obtained more reliably.

The balance may be only inevitable impurities, and an arbitrary element such as B may be added. When adding B, you may contain B in the range of 10-1000 mass ppm with respect to the total mass (total content shown by mass) of elements other than B.
Moreover, 1 or more types selected from Ta, Nb, Al, Cr, Mo, and Co mentioned above may be included (the preferable range of content is also as above-mentioned).

  In addition, in one preferable embodiment, the content of Si and the total content of Ti and Ta are atomic ratios, and Si: (Ti + Ta) = 11.0: 9.2 to 9.7. It has become. As a result, it is possible to realize both high-temperature ductility and high-temperature strength.

2. Sintering Next, sintering is performed using a sintering powder having a desired composition.
Sintering is, for example, a general sintering method in which a powder for sintering is placed in a die and pressure is applied with a punch to obtain a molded body (a green compact) and then heated to a predetermined sintering temperature. May be performed.
In Embodiment 1, by selecting appropriate conditions, most of the obtained sintered body (for example, substantially the entire sintered body) is converted into 75 at% to 85 at% Ni and 8 at% to 13 at% Si. If, it comprises a% Ti of 3at% ~13at, and the crystal structure is L1 ₂ type _Ni 3 (Si, Ti) may be a primary phase comprising an intermetallic compound.
In the manufacturing method according to the present invention, a sintered body having the shape of the final product or a shape close to this (near net shape) can be easily obtained by using the sintering method. That is, a sintered body can be manufactured with high dimensional accuracy.

Sintering while applying pressure to the powder for sintering (pressure sintering) is preferred. This is because the bulk density of the obtained sintered body can be increased and closer to the density (true density) of the melted material.
Note that “applying pressure to the sintering powder” means that when sintering is performed after obtaining the compact, pressure is applied to the sintering powder in the compact by applying pressure to the compact. Including being done.

A preferred example of such a method of sintering while applying pressure to the sintering powder (pressure sintering method) is a hot press.
Examples other than hot pressing include hot isostatic pressing (HIP treatment) or gas pressure sintering after vacuum sintering.

The pressure sintering by the hot press method may be performed as follows.
For example, a lower punch is inserted from below into a through-hole extending in a vertical direction provided in a die made of graphite, and the above-mentioned sintering powder or powder containing the above-mentioned sintering powder is formed inside the through-hole and above the lower punch Place.
Thereafter, an upper punch is inserted from above the through hole, and stress is applied to the upper punch and the lower punch so that a predetermined pressure is applied to the sintering powder.
Then, in a state where a predetermined pressure is applied to the sintering powder, the sintering powder is heated and sintered, for example, by heating a die.
Also, instead of placing the sintering powder or powder containing the sintering powder inside the die through-hole and on the upper part of the lower punch, it is produced using the sintering powder or powder containing the sintering powder. You may arrange the formed object.

Sintering conditions such as the sintering temperature, the heating rate, the sintering time, the stress for pressing the sintering powder (or compact), the sintering atmosphere, etc. when using the hot press method are the composition of the sintering powder used. Then, it may be appropriately adjusted according to the characteristics of the sintered body to be obtained.
Below, suitable conditions are illustrated.

The sintering temperature is preferably 750 ° C to 1050 ° C. Within this temperature range L1 ₂ crystal structure _Ni 3 (Si, Ti) is because it is possible to obtain the phase. More preferably, the sintering temperature is 780 ° C to 1020 ° C. This is because a Ni ₃ (Si, Ti) intermetallic compound can be formed more reliably and higher hardness can be obtained at high temperatures.

The heating rate when heating up to the sintering temperature is preferably 10 ° C./min or less. This is because if the temperature rising rate is too high, the temperature distribution becomes non-uniform and there may be a difference in the characteristics of the sintered body.
Moreover, as for the time hold | maintained at the above-mentioned preferable sintering temperature, 60 minutes-360 minutes are preferable. This is because if the holding time is too short, the densification may be insufficient, and if it is too long, the crystal grains may become coarse and the characteristics may deteriorate (or deteriorate).

The stress applied to the sintering powder (or molded body) is preferably 10 MPa to 60 MPa. This is because if the stress is too low, densification may be insufficient, and if it is too high, the carbon mold may be damaged.
The sintering is preferably performed in a vacuum or in a reduced-pressure atmosphere of an inert gas such as Ar (argon), N ₂ (nitrogen), and He (helium). This is because the powder may be oxidized in an atmosphere containing oxygen, and densification may be inhibited.

Among various sintering methods, a spark plasma sintering (SPS) method is more preferable. This is because the following effects can be obtained by using the discharge plasma sintering method.
1) A higher-density sintered body can be obtained at a relatively low temperature in a short time.
2) The average crystal grain size of the obtained sintered body can be made fine.
3) The running cost is relatively low.

The spark plasma sintering method is a sintering method in which sintering is performed while a pulse current (pulsed current) is passed between particles of a sintering powder (or between green compact particles). In order to obtain the above-mentioned effect more reliably, it is preferable to perform the sintering while applying pressure to the particles of the sintering powder.
As described above, the mechanism for obtaining the above-described effect by flowing a pulsed current, preferably a low voltage pulsed large current, between the particles of the sintering powder (or between the compacted particles) This is probably because the high energy of the discharge plasma generated instantaneously by the spark discharge phenomenon in the gap between the powder particles (or between the green compact particles) promotes thermal diffusion and / or electric field diffusion.
However, it should be noted that this mechanism is estimated based on the obtained effect and is not intended to limit the scope of the present invention.

FIG. 2 is a schematic side view showing a discharge plasma sintering apparatus 100 used for performing discharge plasma sintering.
Details of the discharge plasma sintering method will be described below with reference to FIG.
In the vacuum chamber 30 of the discharge plasma sintering apparatus 100, the sintering powder 10 (or green compact) can be placed in the inside thereof, and the sintering powder 10 in the punch 22 is pressurized (compressed). A punch 22 for applying stress) and a pressurizing device 24 for supplying the punch 22 with stress for pressing (compressing) the sintering powder 10 are arranged.
The punch 22 is electrically connected to a sintering power source (pulse power source) 32 via a pressurizing device 24.
Further, the discharge plasma sintering apparatus 100 has a control device 34. The control device 34 can control the sintering temperature (the temperature of the portion where the sintering powder 10 of the die 20 is disposed), the pulse current, the stress applied to the punch 22 by the pressurizing device 24, and the like. Moreover, the control apparatus 34 is connected with sensors, such as a temperature sensor, as needed, and may perform feedback control using the measurement result of these sensors.

  After placing the sintering powder 10 having a predetermined composition (or the green compact obtained using the sintering powder having the predetermined composition) in the through hole extending in the vertical direction in the die 20, Punches 22 are inserted into the through holes from above and below, respectively.

Then, after the vacuum chamber 30 is evacuated, the sintering powder 10 is pressurized by the pressurizing device 24 via the punch 22, and the sintering powder is supplied from the sintering power source 32 via the device 24 and the punch 22. By applying a pulse current to 10, the sintering powder 10 (or green compact) may be heated to a predetermined sintering temperature.
Note that “applying a pulse current to the sintering powder” means that when sintering is performed after obtaining a compact, a pulse current is applied to the sintering powder in the compact by applying a pulse current to the compact. Including applying a current.

Sintering conditions such as sintering temperature, heating rate, sintering time, stress for pressing the sintering powder 10 (or green compact), pulse current (voltage, current, pulse width, energization time, etc.) are used. What is necessary is just to adjust suitably according to the composition of the powder 10 for sintering, and the characteristic of the sintered compact to obtain.
Examples of suitable conditions are given below.

  The sintering temperature is preferably 750 ° C to 1050 ° C. More preferably, the sintering temperature is 780-1020 ° C. This is because the formation of unreacted particles remaining in the form of particles after sintering can be prevented more reliably.

Moreover, from the viewpoint of increasing the density (lowering the porosity) of the obtained sintered body, the sintering temperature is preferably 800 ° C to 1000 ° C, more preferably 900 ° C to 1000 ° C. This is because at this temperature, a sintered body having sufficient hardness (strength) can be obtained.
Note that the sintering temperature is not limited to the preferred range described above. For example, liquid phase sintering that forms a liquid phase during the sintering may be performed outside the above sintering temperature range (higher temperature).

The rate of temperature rise when raising the temperature to a predetermined sintering temperature is preferably 1 ° C./min to 200 ° C./min. This is because when the heating rate is slower than 1 ° C./min, the productivity is deteriorated, and when the heating rate exceeds 200 ° C./min, it becomes difficult to control to the desired sintering temperature.
Moreover, as for the time hold | maintained at the above-mentioned preferable sintering temperature, 1 minute-60 minutes are preferable. This is because if the holding time is too short, tissue unevenness may occur, and if the holding time is too long, the effect on tissue homogenization may be saturated.

The stress for pressing the sintered body is preferably 0.5 MPa to 50 MPa. If the pressure is too low, the porosity becomes excessively large, and sufficient hardness may not be obtained. This is because if the pressure is too high, the effect is saturated and the carbon mold may be damaged.
Further, the pulse current applied to the sintering powder 10 (or green compact) can be adjusted by an arbitrary method such as appropriately adjusting the on / off value and the current value according to the characteristics of the sintered body to be obtained. You may apply.

3. Heat treatment The composite sintered material (sintered body) produced in this way has an intermetallic compound other than Ni ₃ (Si, Ti) in part of the sintered body (part of the main phase) depending on the sintering conditions. May be formed. Heat treatment may be performed so as to form Ni ₃ (Si, Ti) from at least a part of such a part.
It is preferable to perform a heat treatment that is higher than the sintering temperature and is heated to a temperature of 1100 ° C. or lower, preferably 1080 ° C. or lower, at which no liquid phase is produced.
Even if such a heat treatment is performed, the heat treatment temperature is selected to be lower than the melting temperature at the time of producing the melted material (cast material). Therefore, the Ni ₃ (Si, Ti) metal is used at a lower temperature. Intermetallic compounds can be formed, and the effects of the present application can be obtained.

Examples of suitable conditions are given below.
A preferable heat treatment temperature is 900 ° C to 1050 ° C.
It is preferable to hold at this heat treatment temperature for 0.5 to 72 hours.
The heat treatment is preferably performed in a vacuum or in an inert gas atmosphere such as Ar.

Thus, Ni 3 _(Si, Ti) can be obtained a sintered body having a main phase comprising an intermetallic compound.
In one preferred embodiment, the sintered body according to the present invention is substantially composed entirely of an Ni ₃ (Si, Ti) intermetallic compound.

II. Embodiment 2
In the present embodiment, a sintered body in which a main phase is combined with particles (hard particles) containing at least one selected from metal carbide, nitride, carbonitride, oxide, and boride, and production thereof A method will be described.
In the composite sintered body according to Embodiment 2, in addition to the main phase containing the Ni ₃ (Si, Ti) intermetallic compound shown in Embodiment 1, hard particles are dispersed between (or within) the main phase. doing.

Among hard particles, particles containing at least one selected from Ti carbide, nitride, carbonitride, oxide or boride (hereinafter referred to as Ti carbide, nitride, carbonitride, oxide or boride) The particles containing one or more selected are preferably “Ti compound hard particles (titanium compound hard particles)”.
The reason why the Ti compound particles are preferable is as follows, which is not constraining the technical scope of the present invention, which the inventors consider based on the knowledge obtained so far.
Ti carbides, nitrides, and borides generally have higher hardness values than carbides, nitrides, and borides of other metal elements, and also have melting points and thermal stability (the absolute value of formation energy is large). Since it is high, the effect of improving the height at a high temperature is considered to be greater.
Thus, it is considered that the same effect as the Ti compound hard particles can be obtained if the hard particles have high hardness and high melting point and thermal stability (the absolute value of formation energy is large). Examples of such hard particles include particles containing WB (tungsten boride) (more preferably WB particles).

  In the conventional melt casting method, it was difficult to disperse hard particles such as Ti compound hard particles in a metal / alloy relatively uniformly, but in the present invention, a sintering method is used as will be described in detail later. Therefore, there is an effect that hard particles such as Ti compound hard particles can be uniformly dispersed in the main phase as a matrix.

The sintered body according to the second embodiment includes a metal carbide, a metal nitride, a metal carbonitride, a metal oxide, or a metal contained in the hard particles in addition to the Ni ₃ (Si, Ti) intermetallic compound. Higher hardness due to the presence of one or more selected from the borides (may be described as "metal carbides, nitrides, carbonitrides, oxides and borides") .

  In the present embodiment, metal carbide, nitride, carbonitride, oxide or boride (preferably Ti carbide, nitride, carbonitride, oxide or boride) is used as particles dispersed between the main phases. The particle | grains containing 1 or more types selected from these are used.

Many types of particles are conceivable as hard particles containing metal carbides, nitrides, carbonitrides, oxides and borides dispersed between the main phases. The present inventors obtain desired characteristics depending on the type of particles, such as NbC (niobium carbide), Al ₂ O ₃ (alumina), and SiC (silicon carbide), which are shown as comparative examples in examples described later. It is found that there are cases where it is not possible. However, those skilled in the art can eliminate unsuitable metal carbides, nitrides, carbonitrides, oxides and borides and particles containing these by performing tests and evaluations without undue load. It goes without saying that suitable metal carbides, nitrides, carbonitrides, oxides and borides and particles containing these can be reached.
The inventors of the present application can more reliably obtain higher hardness at high temperatures by using Ti compound hard particles among hard particles. Moreover, when Ti compound hard particle | grains were used, it discovered that the sintered compact which has high hardness also at room temperature and has abrasion resistance at both room temperature and high temperature may be obtained.

A method for manufacturing a sintered body according to Embodiment 2 will be described below.
Hereinafter, an embodiment using Ti compound hard particles suitable as the hard particles will be described.
However, in the present embodiment, the description of the Ti compound hard particles is that the hard particles containing at least one selected from carbides, nitrides, carbonitrides, oxides and borides of metals other than Ti compound hard particles. It should be noted that such hard particles can also be applied as they are (sometimes referred to as “ceramic hard particles”).

1. Preparation of sintering powder containing Ti compound hard particles (1) Ti compound hard particles As described above, Ti compound hard particles are selected from carbide, nitride, carbonitride, oxide or boride 1 Particles containing more than one species, preferably one or more selected from Ti carbides, nitrides, carbonitrides, oxides or borides as a main component (mass ratio of 50% or more).
Examples of such hard particles include TiC particles, TiN particles, TiCN particles, TiO ₂ particles, and TiB ₂ particles.
The particle size of the hard particles is preferably 0.5 to 10 μm. In this case, the particle size may be measured by various methods, and a method using a Fisher sub-sieve sizer can be exemplified as one of the measuring methods.

(2) Mixing of Ti compound hard particles and sintering powder Next, the above-described hard particles and sintering powder (sintering powder shown in the first embodiment) are mixed, and Ti compound hard particles-containing sintering is mixed. Obtain a powder.
For the mixing, various methods used for mixing powders may be used.
For example, when the powder for sintering is a mixed powder in which elemental powder is mixed, when mixing the elemental powder using a pestle and mortar or ball mill, hard particles are added to produce the mixed powder, and the mixed powder and Ti You may mix a compound hard particle simultaneously.
Alternatively, after obtaining a mixed powder in advance using a pestle and mortar or ball mill, the mixed powder and Ti compound hard particles may be put in a bag and mixed, for example, by vibrating the bag.

  When the sintering powder is an alloy powder such as an atomized powder, after obtaining the alloy powder, put the alloy powder and Ti compound hard particles in a bag or mortar, and vibrate the bag or mortar, for example. To obtain a sintering powder containing Ti compound hard particles.

The mixing ratio of the Ti compound hard particles and the sintering powder may be adjusted according to the characteristics of the sintered body to be obtained.
For example, Ti compound hard particles are 10 to 90% by volume, more preferably 10 to 60% by volume, based on Ti compound hard particles-containing sintering powder (that is, the total of Ti compound hard particles and sintering powder). It is.
As the ratio of the Ti compound hard particles is larger, the hardness value of the obtained sintered body tends to be higher.

In place of such a method, for example, a base material for obtaining the composition of the powder for sintering and Ti compound hard particles are mixed in advance, and this mixture is heated to, for example, 2000 ° C. or more to prepare the base material. It may be melted and atomized to obtain an atomized powder containing Ti compound hard particles therein, which may be used as a powder for sintering containing Ti compound hard particles. When the base material is melted to produce the atomized powder, the Ti compound hard particles may be partially or wholly melted.
The base material may be in any form such as an alloy ingot, a pure metal ingot corresponding to each component (that is, a plurality of types of ingots), an alloy powder, a mixed powder, and the like.

2. Sintering Sintering may be performed by the same method as in the first embodiment.
That is, in the sintering method shown in the first embodiment, the sintering can be performed by replacing the sintering powder with the Ti compound hard particle-containing sintering powder.
Other sintering conditions may be the same as those in the first embodiment.

3. At least a portion _(Ni 3 _(Si, Ti) a portion other than the intermetallic compound) of the main phase of the sintered body obtained heat-treated _Ni 3 (Si, Ti) to so as to form an intermetallic compound, as in Embodiment 1 You may heat-process on the same conditions.
The conditions for the heat treatment may be the same as those in the first embodiment.

1. Example 1
1-1. Effect of sintering temperature
(1) Preparation of mixed powder Using the element powder having the powder size (particle diameter) shown in Table 1, a mixed powder having the composition shown in Table 2 (sometimes referred to as “element powder”) was prepared. In addition, about B, it showed with the ratio (mass ppm) with respect to the total mass of elements other than B.
Mixing was performed using a mortar and pestle for 30 minutes.

(2) Sintering Using the obtained mixed powder (sintering powder) of Example 1-1, the discharge plasma sintering apparatus 100 (Sumitomo Coal Mining (currently Fuji Radio Engineering) Co., Ltd.) shown in FIG. Spark plasma sintering was performed by SPS-1020).
Two types of samples having a sintering temperature of 800 ° C. and 900 ° C. were prepared.
At any sintering temperature, the atmosphere was sintered in vacuum, at a heating rate of 100 ° C./min, a holding time of 5 minutes, a pressing force of 30 MPa, and a pulse current on / off ratio of 12/2.
(3) Heat treatment (homogenization treatment)
The obtained sintered body sample was cut out with an electric discharge machine and then subjected to homogenization heat treatment in vacuum at 1050 ° C. for 48 hours.

(3) Microstructure observation and X-ray diffraction For both samples with sintering temperatures of 800 ° C. and 900 ° C., the metal structure after sintering (without homogenization treatment) and after homogenization treatment (after heat treatment) was measured with a scanning electron microscope ( While observing with SEM), X-ray diffraction (CuKα) was performed.
FIG. 3A shows the SEM observation result of the sample after sintering at a sintering temperature of 800 ° C., and FIG. 3B shows the SEM observation result of the sample after homogenization treatment at a sintering temperature of 800 ° C.
FIG. 4 (a) is an X-ray diffraction (XRD) result of a sintered sample at a sintering temperature of 800 ° C., and FIG. 4 (b) is an X-ray diffraction of a sample after homogenization at a sintering temperature of 800 ° C. It is a result.
FIG. 5A shows the SEM observation result of the sample after sintering at a sintering temperature of 900 ° C., and FIG. 5B shows the SEM observation result of the sample after homogenization treatment at a sintering temperature of 900 ° C.
6A is an X-ray diffraction result of a sample after sintering at a sintering temperature of 900 ° C., and FIG. 6B is an X-ray diffraction result of a sample after homogenization at a sintering temperature of 900 ° C. .
In FIG. 3B and FIG. 5B, the portion surrounded by the white frame at the lower left portion shows the result of observing the portion surrounded by the white frame at the center at a higher magnification.

FIG. 3 (Hereinafter, figures having the same numerals and different alphabets in parentheses as in FIGS. 3A and 3B may be collectively referred to as numerals in FIG. 3). As can be seen from FIG. 4, when the sintering temperature is 800 ° C., the sintered body is substantially composed of only the main phase, and after sintering, Ni ₃ (Si, Ti) intermetallic compound is recognized in the main phase. However, after the homogenization treatment, the main phase has a two-phase structure composed of a Ni ₃ (Si, Ti) intermetallic compound and a Ni solid solution phase.

On the other hand, when the sintering temperature is 900 ° C., as is apparent from FIGS. 5 and 6, the sintered body is substantially composed of only the main phase, and after sintering, the main phase is Ni ₃ (Si, Ti). Mainly composed of intermetallic compound and Ni solid solution, and contains a small amount of Ni ₃ Ti. After homogenization, the main phase is a two-phase composed of Ni ₃ (Si, Ti) intermetallic compound and Ni solid solution phase. It is an organization.

(5) Bulk density and hardness test results Next, for both 800 ° C. sintered material and 900 ° C. sintered material, the bulk density after sintering and after homogenization treatment and the room temperature hardness after homogenization treatment are measured. did.

The bulk density was determined by the following method.
Each sample was wet-polished to # 1500 with water-resistant emery paper, the dry weight, the weight in water and the water content were measured using a suspended electronic balance, and the bulk density was calculated by the Archimedes method. For comparison, the density measurement was performed in the same manner for the ingots having the same composition. The density (bulk density) was calculated using the following formula (2).

ρ _b = W ₁ ρ ₁ / (W ₂ −W ′) (2)
Here, ρ _b is a density (bulk density), W ₁ is a dry weight, W ₂ is a hydrous weight, and W ′ is a weight in water.

Hardness was determined by the following method.
Each sample was wet-polished to # 1500 with water-resistant emery paper and then buffed with alumina powder. Then, room temperature hardness and high temperature hardness were measured using this polished sample. The room temperature hardness was measured by measuring at 12 points for each sample using a micro Vickers hardness meter, and calculating the average value of 10 measured values excluding the maximum and minimum values. The high-temperature hardness was measured using a Vickers hardness meter at each measurement temperature at five locations, and the average value of the measured values was calculated to be the hardness. The measurement conditions for both room temperature hardness and high temperature hardness were a load of 1 kg and a holding time of 20 seconds.

FIG. 7 shows the bulk density measurement results. For comparison, the density of the melted material is shown by a dotted line in FIG.
FIG. 8 shows a room temperature hardness test result. In FIG. 8, in addition to the average value of hardness, the maximum value and the minimum value of 10 measured values used to calculate the average value are also shown. For comparison, the hardness of the melted material is also shown.

As can be seen from FIG. 7, the bulk density of each sample is a sufficiently high value of 7.7 g / cm ³ or more, and particularly when the sintering temperature is 900 ° C., after the sintering and after the solute treatment. Both samples have a density of about 8.0 g / cm ³ , which is very close to the melted material.
Further, as can be seen from FIG. 8, the samples having both the sintering temperature of 800 ° C. and the sintering temperature of 900 ° C. have an average value of high-temperature hardness as high as 350 HV or higher, which is a level close to that of the molten material. In particular, a sample having a sintering temperature of 900 ° C. has a higher hardness of 370 HV or higher.

1-1. Influence of composition and heat treatment conditions
As shown in Table 3, in addition to Example 1-1 described above, a mixed powder (sintering powder) having the composition of Example 1-2 and Example 1-3 was prepared. In addition, about B, it showed with the ratio (mass ppm) with respect to the total mass of elements other than B.
In all of Examples 1-1 to 1-3, the Si content and the Ti content were set to 11: 9.5 in atomic ratio.

After these sintered powders were sintered at a sintering temperature of 900 ° C. to obtain a sintered body, the obtained sintered body sample was subjected to two conditions of 900 ° C. × 120 hours and 1050 ° C. × 48 hours. Homogenization treatment (heat treatment) was performed in either of the above.
Note that conditions (manufacturing conditions and evaluation conditions) that are not particularly described are the same as those already described in this embodiment (hereinafter, the same applies to other embodiments described below).

The obtained sample was subjected to structure observation by SEM, X-ray diffraction and density measurement.
9 shows SEM observation results after sintering (before homogenization treatment), FIG. 9A shows the metal structure of Example 1-3, FIG. 9B shows the metal structure of Example 1-2, FIG. 9C shows the metal structure of Example 1-1.
10 shows X-ray diffraction results after sintering (before homogenization treatment), FIG. 10 (a) shows the X-ray diffraction results of Example 1-3, and FIG. 10 (b) shows Example 1-. 2 shows the X-ray diffraction result of FIG. 10, and FIG. 10C shows the X-ray diffraction result of Example 1-1.
FIG. 11 shows SEM observation results after homogenization at 900 ° C. for 120 hours, FIG. 11 (a) shows the metal structure of Example 1-3, and FIG. 11 (b) shows the metal structure of Example 1-2. FIG. 11C shows the metal structure of Example 1-1.
FIG. 12 shows the X-ray diffraction results after the homogenization treatment at 900 ° C. × 120 hours, FIG. 12 (a) shows the X-ray diffraction results of Example 1-3, and FIG. 12 (b) shows Example 1 -2 shows the X-ray diffraction result, and FIG. 12 (c) shows the X-ray diffraction result of Example 1-1.
FIG. 13 shows SEM observation results after homogenization at 1050 ° C. for 48 hours, FIG. 13 (a) shows the metal structure of Example 1-3, and FIG. 13 (b) shows the metal structure of Example 1-2. FIG. 13C shows the metal structure of Example 1-1. In FIGS. 13B and 13C, the circled portion is a Ni solid solution phase having a face-centered cubic (FCC) structure.
FIG. 14 shows X-ray diffraction results after homogenization at 1050 ° C. × 48 hours, FIG. 14 (a) shows the X-ray diffraction results of Example 1-3, and FIG. 14 (b) shows Example 1 -2 shows the X-ray diffraction result, and FIG. 14 (c) shows the X-ray diffraction result of Example 1-1.

All samples consist essentially of the main phase.
For a sample after sintering, Example 1-3 and Example 1-2 _Ni 3 main phase in (Si, Ti) but is not observed between the compound metal, in Example 1-1, the main phase, Ni _{3 It} has a two-phase structure composed of (Si, Ti) intermetallic compound and Ni solid solution phase.

With respect to the sample after the homogenization treatment at 900 ° C. × 120 hours, in Example 1-3 and Example 1-2, after sintering, the main phase is composed of Ni ₃ (Si, Ti) intermetallic compound and Ni solid solution. Mainly contains a small amount of Ni ₃ Ti. On the other hand, in Example 1-1, the main phase has a two-phase structure composed of a Ni ₃ (Si, Ti) intermetallic compound and a Ni solid solution phase.

With respect to the sample after the homogenization treatment at 1050 ° C. × 48 hours, in Example 1-3 and Example 1-2, the main phase is a two-phase composed of a Ni ₃ (Si, Ti) intermetallic compound and a Ni solid solution phase. It is an organization. On the other hand, in Example 1-1, the main phase is substantially composed of only the Ni ₃ (Si, Ti) intermetallic compound.

FIG. 15 is a graph showing the bulk density after sintering of the samples of Examples 1-1 to 1-3 and after a homogenization treatment at 1050 ° C. × 48 hours. In the graph of FIG. 15, the horizontal axis is arranged as the Ni content.
In any composition, a bulk density as high as 7.9 g / cm ³ or higher, which is close to the calculated value (dashed line in FIG. 15), is obtained. Moreover, it turns out that the increase in the density by a homogenization process is so large that a sample with few Ni amounts.

2. Example 2
In this example, atomized powder (a kind of alloy powder) was used.

-Preparation of atomized powder The atomized powder which has a composition of Table 4 was obtained.
In Table 4, B is shown as a ratio (mass ppm) to the total mass of other elements.

FIG. 16 is a graph showing the particle size distribution measurement results of the atomized powder obtained. The particle size distribution was measured by the mesh method.
From FIG. 16, it can be seen that the powder has a cumulative frequency of 50% and a maximum frequency diameter of 90 μm and 125 μm.
FIG. 17 is an X-ray diffraction result of atomized powder. Atomized powder used was _Ni 3 (Si, Ti) of L1 ₂ crystal structure alone, it can be seen that does not include other phases.

Using the obtained atomized powder (alloy powder) as a sintering powder, sintering was performed under one of two conditions of a sintering temperature of 900 ° C and 1000 ° C.
After obtaining the sintered body, the obtained sintered body samples (900 ° C. sintered material and 1000 ° C. sintered material) were homogenized (heat treated) at 1050 ° C. × 48 hours.

The obtained sample was subjected to X-ray diffraction, SEM observation of metal structure, density measurement, average crystal grain size measurement, hardness test (room temperature, high temperature), and tensile test.
In addition, about an average crystal grain size measurement, a room temperature hardness test, and a tensile test, the sintering temperature of 900 degreeC mentioned above, homogenization process conditions 1050 degreeC x 48 hours of Example 1-1, 1-2, and 1-3. The sample was also implemented, and the high-temperature hardness test was also performed on the samples of Examples 1-1 and 1-3 having the sintering temperature of 900 ° C. and the homogenization treatment condition of 1050 ° C. × 48 hours.
Moreover, about the sample of Example 1-2 and 1-3 whose sintering temperature is 900 degreeC and homogenization process conditions 1050 degreeC x 48 hours, the fracture surface after a tension test was observed by SEM.

The average crystal grain size was measured by the following method.
For each sample, after the electrolytic polishing, electron backscatter diffraction using SEM: using a sectioning from the pattern Quality map by performing the crystal orientation analysis by (EBSD E lctron B ack s catter D iffraction) Method The average section length L was determined.
And the nominal particle diameter d was computed from the following (3) Formula. When the crystal orientation analysis was performed, the SEM magnification was selected so that 100 or more crystal grains were included in the analysis range, and three samples were analyzed for each sample.
d = 1.128L (3)

18A shows the metal structure observation result of the sample after the homogenization treatment at a sintering temperature of 900 ° C., and FIG. 18B shows the metal structure observation result of the sample after the homogenization treatment at a sintering temperature of 1000 ° C.
FIG. 19 is a graph showing the density measurement results. In the graph of FIG. 19, the horizontal axis is arranged with the sintering temperature.
It can be seen from FIG. 18 that both the sintered body at a sintering temperature of 900 ° C. and the sintered body at 1000 ° C. are composed only of a main phase composed of a Ni ₃ (Si, Ti) intermetallic compound.
18 and 19, each sample has a sufficiently high bulk density of 7.5 g / or more, and the sample having a sintering temperature of 1000 ° C. has a higher bulk density than the sample having a sintering temperature of 900 ° C. It can be seen that voids are observed in the sample having a sintering temperature of 900 ° C., but no void is observed in the sample having a sintering temperature of 1000 ° C.

FIG. 20 (a) shows the average crystal grain size measurement result of Example 1-3 sample, FIG. 20 (b) shows the average crystal grain size measurement result of Example 1-2 sample, and FIG. The average crystal grain size measurement result of the sample of Example 1-1 is shown, and FIG. 20D shows the average crystal grain size measurement result of the sample of Example 2. The number shown in the lower left of each photograph in FIG. 20 is the average crystal grain size of each sample.
It can be seen that the crystal grain size of the sample of Example 2 using the atomized powder is larger than the crystal grain size of the sample of Examples 1-1 to 1-3 using the mixed powder.

FIG. 21 is a graph showing the results of room temperature hardness test.
From FIG. 21, the room temperature hardness of any sample is as high as that of the melted material. Moreover, the tendency for hardness to become high is recognized, so that Ni content decreases. In addition, although the composition is the same, the sample of Example 1-1 and the sample of Example 2 in which the used powder for sintering is mixed powder or alloy powder have substantially the same hardness.

FIG. 22 is a graph showing the high temperature hardness test results. FIG. 22 shows the hardness measured at room temperature, 573 K (300 ° C.), 773 K (500 ° C.), 873 K (600 ° C.) and 1073 K (800 ° C.).
It can be seen that any sample has a high high temperature hardness of about 300 HV or higher at, for example, 1073 K (800 ° C.), and has excellent wear resistance at high temperatures.

FIG. 23 is a graph showing the results of a tensile test.
From FIG. 23, it can be seen that the samples of Examples 1-1 to 1-3 and 2 have higher yield strength than the smelted material and have a practically sufficient elongation at break. Moreover, when Examples 1-1 to 1-3 samples are compared, it can be seen that the yield stress increases as the Ni content decreases.

FIG. 24A shows the SEM observation result of the tensile test fracture surface of Example 1-3 sample, and FIG. 24B shows the SEM observation result of the tensile test fracture surface of Example 1-2 sample.
In the sample of Example 1-3, grain boundary fracture was partially observed, but in the sample of Example 1-2, grain boundary fracture was not observed.

3. Example 3
In this example, the atomized powder (sintering powder) contains Ta.
An atomized powder having the composition shown in Table 5 was obtained.
In Table 5, B is shown as a ratio (mass ppm) to the total mass of other elements.
The conditions for preparing the atomized powder were the same as in Example 2 except for the composition.

Using the obtained atomized powder (alloy powder) as a sintering powder, sintering was performed under one of two conditions of a sintering temperature of 900 ° C and 1000 ° C.
After obtaining the sintered body, the obtained sintered body samples (900 ° C. sintered material and 1000 ° C. sintered material) were homogenized (heat treated) at 1050 ° C. × 48 hours.

  About the obtained sample, the metal structure observation by SEM, X-ray diffraction, the composition analysis by EPMA, the room temperature hardness test, and the bulk density measurement were performed.

FIG. 25A shows the metal structure observation result of the sample after the homogenization treatment at a sintering temperature of 900 ° C., and FIG. 25B shows the metal structure observation result of the sample after the homogenization treatment at a sintering temperature of 1000 ° C.
FIG. 26A shows the X-ray diffraction result of the sample after the homogenization treatment at a sintering temperature of 900 ° C., and FIG. 26B shows the X-ray diffraction result of the sample after the homogenization treatment at a sintering temperature of 1000 ° C.
All samples consist essentially of the main phase.
The main phase of the sample after homogenization at a sintering temperature of 900 ° C. consists essentially of Ni ₃ (Si, Ti) intermetallic compound, and the main phase of the sample after homogenization at a sintering temperature of 900 ° C. is Ni ₃ ( It has a two-phase structure composed of (Si, Ti) intermetallic compound and NiTa intermetallic compound.

Table 6 shows the composition analysis results by EPMA of the main phase of the sample after homogenization at a sintering temperature of 900 ° C. and the main phase of the sample after homogenization at a sintering temperature of 1000 ° C.
Table 6 also shows the nominal (target) composition of the atomized powder for reference.
For B, since the addition amount was very small, a significant value could not be detected by EPMA analysis.
From Table 6, it can be seen that the composition of the homogenized heat treatment sample is almost in accordance with the target composition regardless of whether the sintering temperature is 900 ° C or 1000 ° C.

FIG. 27 is a graph showing the bulk density measurement results after sintering and after homogenization treatment. In FIG. 27, the sintering temperatures are arranged on the horizontal axis.
All the samples have a bulk density almost equal to that of the melted material.

FIG. 28 is a graph showing room temperature hardness after sintering and after homogenization treatment. In FIG. 28, the sintering temperature is arranged on the horizontal axis.
All samples have a high hardness exceeding 400 HV. In particular, when the sintering temperature is 900 ° C., it has the same level of hardness as the smelted material both after sintering and after homogenization.

4). Example 4
4-1. Mixed powder and Ti compound hard particles In this example, a sintered powder containing Ti compound hard particles containing sintering powder is obtained from mixed powder and Ti compound hard particles, and TiC is dispersed between main phases. Got.
The element powder having the powder size (particle diameter) shown in Table 1 was weighed so as to have the composition shown in Table 2, and 0 volume% (Example 4-0) or 10 volume% (Example 4-1) was measured. ), 20% by volume (Example 4-2), 30% by volume (Example 4-3) and 40% by volume (Example 4-4) TiC particles were added and the respective powder samples were mixed using a ball mill. Thus, a sintering powder containing Ti compound hard particles (each 30 grams) was obtained.
The mixing by the ball mill was performed for 24 hours by a wet method using ethanol as a solvent.

The obtained powder for sintering containing Ti compound hard particles was sintered at a sintering temperature of 1000 ° C., and then homogenized at 1050 ° C. for 48 hours.
The obtained sample was subjected to SEM observation of metal structure (measured TiC area ratio (volume ratio) by PC image analysis), X-ray diffraction, room temperature hardness test, high temperature hardness test, and bulk density measurement.

FIG. 29 (a) shows the metal structure observation result after homogenization treatment of the sample of Example 4-1 and FIG. 29 (b) shows the metal structure observation result after homogenization treatment of the sample of Example 4-2. FIG. 29C shows the metal structure observation result after homogenization processing of the Example 4-3 sample, and FIG. 29D shows the metal structure observation result after homogenization processing of the Example 4-4 sample. The numbers in the lower left of each photograph in FIG. 29 are numbers indicating the volume ratio of TiC obtained by PC image analysis.
FIG. 30 is a result of observation at high magnification of the metal structure of the same part of the same sample as FIG. 29, FIG. 30A is a sample of Example 4-1 and FIG. 30B is a sample of Example 4-2. 30 (c) shows the results of Example 4-3 sample, and FIG. 30 (d) shows the results of Example 4-4 sample.
Fig. 31 (a) shows the X-ray diffraction result of the sample of Example 4-1, Fig. 31 (b) shows the X-ray diffraction result of the sample of Example 4-2, and Fig. 31 (c) shows the result of Example 4-. The X-ray diffraction results of three samples are shown, and FIG. 31 (d) shows the X-ray diffraction results of the sample of Example 4-4.
All of the samples of Examples 4-1 to 4-4 after the homogenous treatment are substantially composed of only the main phase and TiC particles dispersed between the main phases. The main phase is substantially Ni ₃ (Si, Ti) It consists only of intermetallic compounds.

FIG. 32 is a graph showing the room temperature hardness of Examples 4-0 to 4-4, in which the horizontal axis represents the volume ratio of TiC particles.
The room temperature hardness increased with an increase in the volume ratio of TiC, and reached 783 HV in Example 4-4 sample.

FIG. 33 is a graph showing the high temperature hardness of Examples 4-0, 4-1, and 4-3. High temperature hardness was measured at room temperature, 300 ° C, 500 ° C, 600 ° C and 800 ° C.
The hardness of Examples 4-1 and 4-3 samples containing TiC particles is higher than that of Example 4-0 samples containing no TiC particles at any temperature.

FIG. 34 is a graph showing the measurement results and theoretical values of bulk density of Examples 4-0 to 4-4. In the graph of FIG. 34, the horizontal axis is arranged with the volume ratio of TiC.
FIG. 35 is a photograph showing voids observed in the metallographic observation of the Example 4-4 sample, and voids are observed in the circled portions.
All samples have a bulk density close to the theoretical value.

4-1. Mixed powder and Ti compound hard particles Ti compound hard particle-containing sintering powder having the same composition and the same volume ratio of TiC as Example 4-3 described above was used as an Example 4-5 sample using atomized powder and TiC powder. Formed.
A sample after the homogenization treatment was obtained by the same method as in Example 4-3 except that the atomized powder having the composition shown in Table 2 was used.

FIG. 36 (a) shows the metal structure observation results of Example 4-5 sample by SEM, and FIG. 36 (b) shows the result of Example 4-5 sample by SEM at a higher magnification than FIG. 36 (a). It is a metal structure observation result.
In FIG. 36 (a), the gray spherical portion (the portion that appears round and gray on the photograph) is the Ni ₃ (Si, Ti) phase, and the black region is the TiC particle. Because the particle size of the atomized powder used was relatively coarse, at first glance, it seems that Ni ₃ (Si, Ti) powder is embedded in the TiC particles and mixed, but from the enlarged photograph of FIG. Ni ₃ (Si, Ti) has spread to every detail of the above, and voids and defects are not generated between the Ni ₃ (Si, Ti) phase and the TiC particles, and the sintering is performed well. I understand that.

5. Example 5
In this example, TiB ₂ particles were used as compound hard particles, and a sintered body in which TiB ₂ particles were dispersed between main phases was obtained.
The elemental powder was weighed so as to have the composition of Example 5A shown in Table 7, and 0% by volume (Example 5-0), 10% by volume (Example 5-1), and 20% by volume (Example 5). -2), 30 volume% (Example 5-3) and 40 volume% (Example 5-4) of TiB ₂ particles added thereto, each powder sample (30 grams each) was mixed by a ball mill and sintered. Powder (Examples 5-1 to 5-4 are powders for sintering containing Ti compound hard particles).
The mixing by the ball mill was performed for 24 hours by a wet method using ethanol as a solvent.
Further, an atomized powder was prepared so as to have the composition of Example 5B shown in Table 7, and this atomized powder and TiB ₂ particles were mixed using a mortar, and Ti compound hard particles-containing sintering of Example 5-5 A powder was obtained.
In Table 7, B is shown as a ratio (mass ppm) to the total mass of other elements.

The obtained powder for sintering (Ti compound hard particle-containing powder for sintering) was sintered at a sintering temperature of 1000 ° C., and then homogenized at 1050 ° C. for 48 hours.
About the obtained sample, the metal structure observation by a room temperature hardness test, a high temperature hardness test, X-ray diffraction, and SEM was performed.

FIG. 37 is a graph showing the room temperature hardness test results after homogenization treatment of samples 5-0 to 5-4, and the horizontal axis is the volume ratio of TiB ₂ particles.
As the volume ratio of TiB ₂ particles increases, the room temperature hardness increases, and in Example 5-4, it is 1300 HV or higher.

FIG. 38 shows Example 5-0 (0% TiB ₂ ), Example 5-1 (10% TiB ₂ ) and Example 5-3 sample (30% TiB ₂ ) after homogenization and for comparison. It is a graph which shows the high temperature hardness of WC-Co which has the abrasion resistance in the highest level as the practical material used. High temperature hardness was measured at room temperature, 300 ° C, 500 ° C, 600 ° C and 800 ° C.
Examples 5-1 and 5-3 show higher hardness (wear resistance) than WC-Co at 800 ° C. In addition, the sample of Example 5-3 shows a hardness comparable to that of WC-Co at room temperature and a hardness higher than that of WC-Co at a temperature of 300 ° C. or higher.

FIG. 39 is an X-ray diffraction result of the sample of Example 5-5 after the homogenization treatment.
FIG. 40 (a) is a metal structure observation result of the sample of Example 5-3 after the homogenization treatment, FIG. 40 (b) is an enlarged photograph of FIG. 40 (a), and FIG. 40 (c) is homogenization. It is a metal-structure observation result of Example 5-5 sample after a process, FIG.40 (d) is an enlarged photograph of FIG.40 (c). The numbers in the upper right of each photograph in FIG. 40 indicate the room temperature hardness.

The sample of Example 5-5 after the homogenization treatment includes a main phase of a multiphase structure containing Ni ₃ (Si, Ti) intermetallic compound, Ni ₃ B intermetallic compound, and Ni ₁₆ Ti ₆ Si ₇ intermetallic compound. And TiB ₂ particles dispersed between the main phases.

6). Comparative Example A sample using NbC particles, SiC particles, and Al ₂ O ₃ particles was produced in place of the Ti compound hard particles of Example 4 (conditions not specifically described are the same as those of Example 4).

  In a sintered body (mixed alloy powder and NbC particles with a mortar and pestle) containing 10% and 30% by volume of NbC particles, the interface between the main phase and the NbC particles in the hardness test after homogenization treatment The problem of exfoliation (sufficient hardness and toughness considered to be caused by insufficient wettability between the main phase and the NbC particles) occurred.

In a sintered body containing 30% Al ₂ O ₃ particles by volume (element powder and Al ₂ O ₃ particles are mixed for 24 hours in a ball mill), the powder is separated during ball mill mixing, and the Al ₂ O ₃ particles are Solidified and adhered. After re-grinding, sintering was performed, but partly dissolved. Although the homogenized sintered body was polished for surface observation, a glossy surface was not obtained (insufficient toughness).

  A sintered body containing 30% by volume SiC particles (element powder and SiC particles mixed for 24 hours with a ball mill) cracked when processed with a microcutter to obtain a sample for evaluation after homogenization. (Insufficient toughness).

Claims (9)

And 75at% ~85at% of nickel (Ni), and 8at% ~13at% of silicon (Si), and 3at% ~13at% of titanium (Ti), based on the total weight of elements other than Bo Ron (B) and 10mass ppm~1000mass ppm of boron (B), a main phase consisting of _Ni 3 (Si, Ti) intermetallic compound is a main phase consisting of unavoidable impurities, crystal structure L1 ₂ type,
Carbides, nitrides of titanium (Ti), carbonitride, a Ti compound hard particles comprising at least one selected from oxides and borides of Ti compound hard particles dispersed during the main phase,
A sintered body comprising: The sintered body according to claim 1, wherein the main phase further includes at least one of a Ni ₃ B intermetallic compound and a Ni ₁₆ Ti ₆ Si ₇ intermetallic compound. The sintered body according to claim 1, wherein the Ti compound hard particles are at least one selected from TiC particles, TiN particles, TiCN particles, TiO ₂ particles, and TiB ₂ particles. The main phases are tantalum (Ta): 0.5 at% to 8 at%, niobium (Nb): 0.5 at% to 4 at%, aluminum (Al): 0.5 at% to 8 at%, chromium (Cr): 0 2. At least one selected from 5 at% to 8 at%, molybdenum (Mo): 0.5 at% to 8 at%, and cobalt (Co): 0.5 at% to 4 at% is further included. The sintered body according to any one of -3. And 75at% ~85at% of nickel (Ni), and 8at% ~13at% of silicon (Si), and 3at% ~13at% of titanium (Ti), based on the total weight of elements other than Bo Ron (B) A powder preparation step of preparing a mixed powder or alloy powder composed of 10 mass ppm to 1000 mass ppm of boron (B ) and inevitable impurities;
The mixed powder or alloy powder is mixed with Ti compound hard particles containing at least one selected from carbide, nitride, carbonitride, oxide and boride of titanium (Ti), and contains Ti compound hard particles Preparing a powder;
While applying a pressure to the Ti compound hard particles-containing powder, heating the Ti compound hard particles-containing powder, the crystal structure is L1 ₂ type Ni 3 _(Si, Ti) a main phase consisting of an intermetallic compound A sintering step of forming a sintered body comprising the hard particles dispersed between the main phases;
A method for producing a nickel (Ni) -based intermetallic compound sintered body comprising: The manufacturing method according to claim 5, wherein the main phase further includes at least one of a Ni ₃ B intermetallic compound and a Ni ₁₆ Ti ₆ Si ₇ intermetallic compound. The mixed powder or alloy powder is tantalum (Ta): 0.5 at% to 8 at%, niobium (Nb): 0.5 at% to 4 at%, aluminum (Al): 0.5 at% to 8 at%, chromium (Cr ): 0.5 at% to 8 at%, molybdenum (Mo): 0.5 at% to 8 at% and cobalt (Co): at least one selected from 0.5 at% to 4 at% The manufacturing method according to claim 5 or 6. And 75at% ~85at% of nickel (Ni), and 8at% ~13at% of silicon (Si), and 3at% ~13at% of titanium (Ti), based on the total weight of elements other than Bo Ron (B) A base material composed of 10 mass ppm to 1000 mass ppm of boron (B ) and unavoidable impurities, and at least one selected from carbides, nitrides, carbonitrides, oxides and borides of titanium (Ti), Using a melting step to obtain a molten metal in which at least the base material is melted;
By atomizing the molten metal, and 75at% ~85at% of nickel (Ni), and 8at% ~13at% of silicon (Si), and 3at% ~13at% of titanium (Ti), except Bo Ron (B) In a nickel-based alloy matrix composed of 10 mass ppm to 1000 mass ppm of boron (B ) and unavoidable impurities with respect to the total mass of the elements, titanium (Ti) carbide, nitride, carbonitride, oxide and boron An atomizing step to obtain an atomized powder having at least one selected from a compound;
The atomized powder is heated with pressure applied, 75 at% to 85 at% nickel (Ni), 8 at% to 13 at% silicon (Si), 3 at% to 13 at% titanium (Ti) , Ron (B) other than the 10mass ppm~1000mass ppm based on the total weight of the elements boron (B), consists inevitable impurities, and _Ni 3 crystal structure is a L1 ₂ type (Si, Ti) intermetallic A main phase composed of a compound, and Ti compound hard particles containing at least one selected from carbide, nitride, carbonitride, oxide and boride of titanium (Ti) dispersed between the main phase. Obtaining a sintered body comprising:
A method for producing a nickel (Ni) -based intermetallic compound sintered body comprising: The base material, the nickel-based alloy matrix, and the main phase are tantalum (Ta): 0.5 at% to 8 at%, niobium (Nb): 0.5 at% to 4 at%, aluminum (Al): 0.5 at%. At least one selected from ˜8 at%, chromium (Cr): 0.5 at% to 8 at%, molybdenum (Mo): 0.5 at% to 8 at%, and cobalt (Co): 0.5 at% to 4 at% Furthermore, it contains, The manufacturing method of Claim 8 characterized by the above-mentioned.