JP5850372B2 - Grain refiner for casting and method for producing the same - Google Patents

Description

  The present invention relates to a crystal grain refiner for casting and a method for producing the same.

One typical processing method for metals and alloys is the melt processing method. The melt processing method has an advantage that a product having a complicated and smooth shape can be produced and can be applied to any metal and alloy which are difficult to process. Solidification is the most important phase change in melt processing. Solidification involves nucleation and includes homogeneous and heterogeneous nucleation. By adding heterogeneous nuclei, the solidified structure, that is, the cast structure can be refined. Here, the refinement of the material structure is one of various material strengthening methods, and is known as a method for strengthening a material without impairing ductility and toughness. It is known that the hole-petch relationship shown in Formula (1) is established between the yield stress σ _{y of the} polycrystalline body and the crystal grain size d.

In the equation, σ ₀ is called a frictional stress with respect to dislocation motion, and k is a Hall-Petch coefficient, both of which are constants depending on the material. In order to become an inhomogeneous nucleus effective in solidification, the interface energy between the heterogeneous nucleus material and the cast material needs to be small. According to Non-Patent Document 1, the effectiveness of heterogeneous nuclear material can be discussed by the degree of inconsistency δ of atomic arrangement in one direction on the low index plane of the crystal lattice of the cast material and the heterogeneous nuclear material. This inconsistency δ is expressed by the following formula (2).

Here, a is the lattice constant of the low index surface of the heterogeneous nuclear material, and a ₀ is the lattice constant of the low index surface of the cast material. The smaller δ, the better the alignment of the atomic arrangement and the lower the interfacial energy. When this value is 10% or less, it works effectively as a heterogeneous nucleus.

Al ₃ Ti, TiB ₂ and Al ₃ Zr are known as substances that can be heterogeneous nuclei of aluminum crystals, and Al—Ti alloys and Al—Ti—X (X = B, C) alloys have crystal grains. As a micronizing agent, it is used at the production site of cast aluminum (for example, refer to Patent Documents 1 and 2). Here, Al ₃ Ti and Al ₃ Zr which are intermetallic compounds have a D0 ₂₂ structure and a D0 ₂₃ structure, respectively.

Among these materials, especially the role of the grain refiner of Al 3 _Ti of the D0 ₂₂ structures are important. As shown in FIG. 1 (a) and (b), the lattice constants of the _Al 3 Ti of pure Al and _{D0 22} structures are respectively 0.40496nm and 0.384 nm, the value of the mismatch δ 5% Degree.

  Further, the crystal grain refining ability depends on the number of heterogeneous nuclei in the crystal grain refiner. Patent Document 1 shows that the number of heterogeneous nuclei can be controlled and the crystal grain refinement ability is improved by applying giant strain processing to the crystal grain refiner.

By the way, the D0 ₂₂ structure intermetallic compound has poor crystal symmetry as shown in FIG. Therefore, good symmetry L1 ₂ structure by adding an additional element is studied to change to (FIG. 1 (c)) has been actively (e.g., see Non-Patent Documents 2, 3, and 4). As a result, L12 _two- structure intermetallic compounds having various lattice constants have been found. Unfortunately, practical application of the L1 ₂ structure intermetallic compound thus obtained is not performed. This is because pores are formed during solidification and tensile ductility is not achieved. Even attempts to use L1 ₂ structure intermetallic compound in bulk, without strength enough to be assumed.

JP 2005-329459 A Japanese Patent Laid-Open No. 10-317083

Turnbull and Vonnegut, Ind. Eng. Chem., 1952. Metal. Trans. A, Vol. 23A, 1992, 2963. Mater.Sci.Eng.A, Vol.A192 / 193, 1995, 92. Masaharu Yamaguchi, Metals, Vol.62, No.10, 1992, 2.

Incidentally, as described above, D0 ₂₂ value of mismatch [delta] of the Al 3 _Ti of the structure is about 5%, if, as long give a compound having the same following mismatch [delta], more sophisticated refining Can be an additive.

  Furthermore, since the lattice constant of an aluminum alloy is different from that of pure Al, there should be an optimum refinement additive for each individual aluminum alloy.

Further, as shown in FIG. 1B, Al ₃ Ti having a D0 ₂₂ structure has a = 0.384 nm and c = 0.8596 nm, and the lattice constant differs depending on the crystal plane. The value of δ will be different. Therefore, Al ₃ Ti having a D0 ₂₂ structure has different functions as heterogeneous nuclei depending on crystal planes.

Incidentally, as process variables affecting the refinement of crystal grains of the cast material, there are a holding time after adding the crystal grain refining agent to the melt, in addition to the melt temperature and the addition amount. The amount of Al-5 mass% Ti-X (X = B, C) alloy currently used as a grain refiner is 1 mass% or less. Therefore, the titanium concentration in the molten metal is 0.05% by mass or less, and as shown in FIG. 2, Al ₃ Ti heterogeneous nuclei cannot exist in the molten metal in an equilibrium state at this concentration. However, by adjusting the holding time, non-equilibrium nuclei in a non-equilibrium state are used at the cast aluminum manufacturing site. Considering this more deeply, the crystal grain refining agent itself may not be an equilibrium system. That is, it should be possible to use intermetallic compounds that cannot originally exist stably in an equilibrium state for heterogeneous nuclei.

  In view of the above points, the present invention has a smaller incompatibility δ as compared with inhomogeneous nuclei in existing grain refiners, and infinitely less inconsistency δ than pure Al or Al alloys. It is an object of the present invention to provide a refined additive having a heterogeneous nucleus and a method for producing the same.

The present invention is a completely different viewpoint from the study of the L1 ₂ structure intermetallic compound described above are those handling the L1 ₂ structure intermetallic compound.

That is, according to the invention described in claim 1, L1 ₂ particles of the intermetallic compound represented by the following formula (1) of the structure, solid of the casting crystal grains is dispersed in the mother phase composed mainly of Al It is a fine agent.
(Al, Y) ₃ Z (1)
(Y is any one selected from Cu, Fe, Ni, Zn, Pd, Cr, Mn, Co, Ag, Rh, Pt, Au and Hf, and Z is selected from Ti, Zr and Zn. Any one being.)
As the crystal grain refining agent for casting, as in the invention described in claim 2, Z in the formula (1) can be Ti. For example, in claim 3, 4, 5 As in the present invention, the intermetallic compound may be Al ₅ CuTi ₂ , Al ₂₂ Fe ₃ Ti ₈ or Al ₆₇ Ni ₈ Ti ₂₅ .

L1 ₂ as in formula of structure (1), it or replace replace a part of Al in the _Al 3 Ti of the _{D0 22} structures other elements, the Ti in the _Al 3 Ti of the _{D0 22} structures other elements Thus, the lattice constant of the intermetallic compound can be changed. Therefore, the lattice constant of the intermetallic compound, as compared with Al 3 _Ti of the D0 ₂₂ structures, it becomes possible to approach the lattice constant of pure Al, by selecting the other elements replacing individual Al It is possible to approach the lattice constant of the alloy.

  As a result, compared with the inhomogeneous nuclei in the existing grain refiner, the degree of inconsistency δ is smaller, and the refined additive that has an inconsistency δ that is infinitely smaller than that of pure Al or Al alloys. Provision is possible.

For example, if you make a third element Y _Al 3 Ti of the _{D0 22} structures, the L1 ₂ structure as shown in (c) of FIG. 1 (Al, _Y) becomes a 3 Ti intermetallic compound, in this case The degree of mismatch δ with respect to the lattice constant a and pure Al is as follows. Since these lattice constants are close to the lattice constant of pure Al as compared with Al ₃ Ti of the D0 ₂₂ structure, these intermetallic compounds are more mismatched as compared with Al ₃ Ti of the D0 ₂₂ structure. It can be said that it is a small heterogeneous nucleus of degree δ.

Y = Cu: Al ₅ CuTi ₂ , a = 0.3927 nm, δ = 3.0
Y = Fe: Al ₂₂ Fe ₃ Ti ₈ , a = 0.393 nm, δ = 3.0
Y = Ni: Al ₆₇ Ni ₈ Ti ₂₅ , a = 0.394 nm, δ = 2.7
Y = Zn: Al ₆₆ Zn ₉ Ti ₂₅ , a = 0.396 nm, δ = 2.2
Also, intermetallic compounds L1 ₂ structure used in the present invention are, for example, as shown in FIG. 1 (c), a lattice constant in all crystal faces same, the same act as heterogeneous nuclei all crystal planes Have

  The above-mentioned crystal grain refiner for casting can be produced by using a discharge plasma sintering method. Moreover, the above-mentioned crystal grain refiner for casting may be in a semi-sintered state that is not a dense sintered body.

It is a figure which shows the crystal structure and lattice constant of Al of fcc structure. It is a diagram showing an _Al 3 Ti crystal structure and lattice constant of the D0 ₂₂ structures. L1 ₂ structure (Al, _Y) is a diagram showing a crystal structure and lattice constant of 3 Ti. It is a binary system equilibrium state diagram of Al-Ti, and is a diagram showing a range where Ti is 0-30 wt%. Is a diagram showing an X-ray diffraction measurement results of the _Al 5 CuTi ₂ samples after homogenization of Example 1. FIG. 3 is a diagram showing the results of X-ray diffraction measurement of the bulk crystal grain refining agent of Example 1. 2 is a scanning electron micrograph of the bulk crystal grain refining agent of Example 1. FIG. It is a schematic diagram of FIG. 5A. 3 is a scanning electron micrograph showing a cross section of an Al cast material of Comparative Example 1. FIG. It is a schematic diagram of area | region A1 in FIG. 6A. 2 is a scanning electron micrograph showing a cross section of an Al cast material of Example 1. FIG. It is a schematic diagram of area | region A2 in FIG. 7A. It is a figure which shows the average crystal grain diameter of Al cast material in Examples 1-12. 10 is a scanning electron micrograph showing a cross section of an Al cast material of Example 9. FIG. It is a schematic diagram of area | region A3 in FIG. 9A.

  The present invention provides a grain refining agent containing a heterogeneous nuclear material with a low degree of inconsistency. Here, the heterogeneous nuclear material has a degree of inconsistency of 5 or less, preferably 4 or less.

The grain refiner, the particles of the intermetallic compound represented by the formula L1 ₂ structure as a heterogeneous nuclear material (1), Al those solid form obtained by dispersing the matrix composed mainly of is there.

This intermetallic compound cannot originally exist stably in an equilibrium state with Al. Examples of the intermetallic compound include L1 ₂ structure (Al, Y) ₃ Ti and L1 ₂ structure (Al, Y) ₃ Z. Specifically, Al ₅ CuZr ₂ : a = 0.404 nm, Al ₂ There are HfZn: a = 0.4033 nm, Al ₅ NiZr ₂ : a = 0.406 nm and those shown in Table 1, which are close to the lattice constant of 0.40496 nm of Al.

Note that the intermetallic compound used in the present invention are preferably those which can not exist stably in the original Al equilibrium, as compared with Al 3 _Ti of the D0 ₂₂ structures, small non more mismatch δ As long as it can be a homogeneous nucleus, it can be stably present in an equilibrium state with Al.

  The parent phase containing Al as the main component means a parent phase containing Al as the most component and containing pure Al or an Al alloy as a component. From the viewpoint of suppressing fluctuations in the composition of the cast material, the parent phase is preferably the same as the components of the cast material. That is, in the production of a pure Al cast material, the parent phase is preferably pure Al, and in the production of an Al alloy cast material, the parent phase is preferably the same Al alloy as the components of the cast material.

Even if particles of the intermetallic compound represented by the formula (1) having a powdery L1 ₂ structure are directly added to the molten metal, the particles float from the wettability relationship. Therefore, grain refiner of the invention, the particles of the intermetallic compound of the formula (1) of the L1 ₂ structure employing a solid structure dispersed in the mother phase (bulk). Thus, upon addition of grain refiner to the molten metal, L1 an intermetallic compound represented by ₂ structure formula (1) can function effectively as a heterogeneous nucleus is dispersed in the melt.

  Also, if the volume fraction of the intermetallic compound particles relative to the entire crystal grain refining agent is too large, the intermetallic compound particles cannot be dispersed when the crystal grain refining agent is added to the melt, and the volume If the fraction is too small, a large amount of crystal grain refining agent must be added, which is not industrially preferable. Therefore, the intermetallic compound particles preferably have a volume fraction of 5 to 40% with respect to the whole crystal grain refining agent.

Further, Al and L1 ₂ structure (Al, Y) 3 to the intermetallic compound represented by formula (1), such as _Ti can not exist in equilibrium, bulk dispersed particles of the intermetallic compound in the Al If it is going to manufacture this, the sintering in low temperature and a short time which is the conditions which this intermetallic compound does not decompose | disassemble is needed.

  In contrast, the spark plasma sintering method (SPS) can be sintered at a low temperature in a short time, and therefore can be bulked even in a non-equilibrium system. Therefore, after forming the compact by mixing the powder of the intermetallic compound and the powder of the parent phase, the compact is sintered by SPS, thereby producing a crystal grain refining agent for casting.

  In general, when sintered at a low temperature in a short time by a sintering method other than SPS, the mechanical strength of the obtained sintered material is lowered, but the mechanical strength of the sintered material itself is not a problem. Therefore, it can be used for the grain refiner even in a semi-sintered state. For this reason, a grain refiner for casting is produced using a sintering method such as hot pressing, hot isostatic pressing, or normal pressure sintering after cold isostatic pressing without using SPS. You can also. The “semi-sintered state” means that the filling rate is 70 to 90%. The “filling rate” is calculated by measuring the area fraction of pores by image analysis from a structure photograph taken with an optical microscope and subtracting it from 100%. Hot isostatic pressing is a technique in which high-temperature and high-pressure gas is used as a medium to compress and densify the object to be processed. Cold isostatic pressing and filling a rubber mold with powder. The method of forming by applying hydrostatic pressure.

  By adding the above crystal grain refiner for casting to a melt of pure Al or Al alloy and pouring this melt into a mold, a pure Al or Al alloy cast material is produced, thereby producing a pure Al cast material. And the structure of Al alloy cast material is refined and made uniform. At this time, as can be seen from Examples 1 to 10 described later, it is possible to optimize the refinement of the crystal grains of the cast material by adjusting the holding time.

Example 1
In Example 1, Al ₅ CuTi ₂ having a relatively wide composition range in the L1 ₂ structure intermetallic compound is selected and prepared as a sample, but this does not define the heterogeneous nuclear material. . As the sample raw material, bulk Al-40 mass% Cu alloy, powdered pure Al and pure Ti are used, but this does not define the raw material. These were arc melted in an argon atmosphere to prepare a bulk sample. In order to ensure homogeneity during arc melting, melting was performed at least 7 times after the raw materials were melted together.

  Next, the sample as arc melted was cut into a rectangular parallelepiped. After that, it was placed on an alumina plate, placed in the middle of the soaking zone of an infrared gold image furnace, and homogenized in vacuum at 1100 ° C. for 1 hour.

The produced Al ₅ CuTi ₂ was evaluated for its crystal structure and structure. Although the second phase was observed in the sample as arc-melted, but not observed after the homogenization treatment, it is considered that the atoms were sufficiently diffused by the homogenization treatment. A part of the sample was cut out and ground with a hammer, and then the crystal structure was evaluated using X-ray diffraction. In FIG. 3, the measurement result of the X-ray diffraction of the sample after a homogenization process is shown. As shown in the figure, the peak pattern of Al ₅ CuTi ₂ is shown. When the lattice constant is calculated from this result, a = 0.3917 nm, which is almost the same as the literature value.

In order for the produced L1 ₂ structure intermetallic compound Al ₅ CuTi ₂ to act as an inhomogeneous nucleus in the molten Al, it must be powdered to reduce the particle size. However, even if powdered Al ₅ CuTi ₂ is added directly to the molten Al, it floats from the wettability relationship, so there is a high possibility that the powdered Al ₅ CuTi ₂ will not be dispersed. Therefore, a crystal grain refining agent in which Al ₅ CuTi ₂ particles are dispersed in an Al matrix is prepared using a discharge plasma sintering method.

First, the produced bulk Al ₅ CuTi ₂ was pulverized with a hammer, and a powder having a particle size of 75 μm to 150 μm was produced using 150 μm and 75 μm sieves. A compact is formed by mixing with powdered pure Al so that the volume fraction of the produced Al ₅ CuTi ₂ powder is 10%, and a small discharge plasma sintering apparatus (Sumitomo Coal Mining Co., Ltd., Doctor Using a Sinter series, SPS-515S), the compact was sintered to produce a bulk refiner. At this time, the molding pressure was 45 MPa, the heating rate was 100 ° C. per minute, the sintering temperature was 500 ° C., and the holding time was 5 minutes.

The measurement result of the X-ray diffraction of the produced bulk crystal grain refiner is shown in FIG. A peak pattern of Al occupying 90% of the volume ratio is strong, but a peak pattern of Al ₅ CuTi ₂ is also clearly shown. From this result, it can be confirmed that Al ₅ CuTi ₂ remains without reacting.

This sample was cut, wet-polished using Emily paper from # 100 to # 4000, and then observed with an SEM. The results are shown in FIGS. FIG. 5B is a schematic diagram of FIG. 5A. As shown in these figures, it can be observed that Al ₅ CuTi ₂ particles powdered remain in the sample. Further, since a clear interface can be observed, it can be seen that the Al ₅ CuTi ₂ particles do not react with the Al matrix.

Thus, by sintering at a low temperature and in a short time, the L1 ₂ structure intermetallic compound Al ₅ CuTi ₂ that becomes an inhomogeneous nucleus of the Al cast material remains in the sample without reacting, and between the L1 ₂ structure metals. It became possible to produce a crystal grain refining agent having a compound Al ₅ CuTi ₂ heterogeneous nucleus.

  Next, a casting experiment was performed using the produced crystal grain refining agent. First, 148.8 g of pure Al ingot was dissolved in a crucible at 750 ° C., and 1.2 g (addition amount 0.8% by mass) of a micronizing agent was added. The addition amount of the micronizing agent in this experiment was set so that the Ti concentration would be a sufficiently low value compared to 0.12% by mass, which is the peritectic composition in the Al—Ti binary system. Further, immediately after the addition of the crystal grain refining agent, the mixture was stirred for 30 seconds, and the subsequent holding time was 0 second.

  As Comparative Example 1, 148.8 g of pure Al ingot was dissolved in a crucible at 750 ° C., and a similar experiment was performed by adding 1.2 g of pure Al. Then, it cut | disconnected in the 5 mm part from the bottom face of Al cast material, and made the upper surface the observation surface. Wet polishing from emery paper # 80 to # 4000 was performed, and buffing using 1 μm alumina was performed. Thereafter, etching was performed for 90 seconds using a 10% hydrofluoric acid aqueous solution.

  FIG. 6A shows a cross-sectional photograph of the sample of Comparative Example 1 in which no crystal grain refining agent is used, and FIG. 7A shows a sample of Example 1 in which the crystal grain refining agent is added. FIGS. 6B and 7B show schematic diagrams of regions A1 and A2 in FIGS. 6A and 7A, respectively. In a sample to which no crystal grain refining agent was added, a normal solidified structure having equiaxed crystals and columnar crystals is observed. On the other hand, it can be seen that the structure of the sample to which the micronizing agent is added is almost uniform although columnar crystals are observed in part, and is refined as a whole.

In addition, the crystal grains in the region that was a columnar crystal are almost equiaxed. When the average particle size was measured using the average linear intercept method, the crystal grain size was 1353 μm in the sample to which the crystal grain refiner was not added, whereas the crystal grain refiner was added. In the sample, the crystal grain size was refined to 851 μm.
(Examples 2 to 10)
In Examples 2 to 5, in the casting experiment using the grain refiner produced in Example 1, the holding time after stirring for 30 seconds immediately after the addition of the grain refiner was 120 seconds, They were 210 seconds, 300 seconds, and 600 seconds. Other conditions are the same as in the first embodiment.

Moreover, in Examples 6-10, in the manufacture of the crystal grain refining agent in Example 1, the volume fraction of the Al ₅ CuTi ₂ powder was changed to 20%. And the casting experiment was done using the manufactured crystal grain refiner. At this time, the addition amount of the micronizing agent was 0.4 mass fraction, and the retention times after stirring for 30 seconds immediately after the addition of the crystal grain micronizing agent were 0 seconds, 210 seconds, 300 seconds, 480 seconds, and 600, respectively. Seconds. Other conditions are the same as in the first embodiment.

  In FIG. 8, the average crystal grain diameter of the Al casting material in Examples 2 to 10 is shown. FIG. 8 also shows the results of Example 1 and Examples 11 and 12 described later.

  It can be seen that also in Examples 2 to 5 in which the volume fraction was 10% and the retention time was longer than 0 seconds, the crystal grain size was refined. In the case of a volume fraction of 10%, the crystal grain size was a minimum of 344 μm when the holding time was 300 seconds.

  It can be seen that also in Examples 6 to 10 in which the volume fraction was 20%, the crystal grain size was refined. In the case of a volume fraction of 20%, when the retention time of Example 9 was 480 seconds, the crystal grain size was a minimum of 439 μm.

FIG. 9A shows a cross-sectional photograph of the sample of Example 9, and FIG. 9B shows a schematic diagram of a region A3 in FIG. 9A. It can be seen that the sample of Example 9 has a substantially uniform structure and is refined as a whole.
(Examples 11 and 12)
Al ₂₂ Fe ₃ Ti ₈ and Al ₆₇ Ni ₈ Ti ₂₅ were produced by arc melting, vacuum sealed, and homogenized at 1200 ° C. for 24 hours, 1100 ° C. for 100 hours, respectively.

In the same manner as in Example 1, the produced bulk Al ₂₂ Fe ₃ Ti ₈ and Al ₆₇ Ni ₈ Ti ₂₅ were pulverized and classified into powders of 75 to 150 μm. This was mixed with powdered pure Al (99.9%) at a volume fraction of 10%, and then a finer was prepared by SPS.

  Next, a casting experiment was performed using the produced finer. The conditions are the same as in Example 1.

Both Al castings produced by adding the micronizing agents of Examples 11 and 12 had a substantially uniform structure and were refined as a whole. When the average particle diameter was measured using the average linear intercept method, as shown in FIG. 8, when the micronizing agent having Al ₂₂ Fe ₃ Ti ₈ of Example 11 as a heterogeneous nucleus was added, the Al casting material The α-Al crystal grain size was 642 μm, and in the case of Al ₆₇ Ni ₈ Ti ₂₅ of Example 12, it was 260 μm. From these results, the crystal grain refining performance of the refining agent using Al ₂₂ Fe ₃ Ti ₈ and Al ₆₇ Ni ₈ Ti ₂₅ was confirmed.

  From the above results, the structure of the Al cast material is refined and made uniform by adding the crystal grain refining agent produced through the series of processes of the above-described embodiments.

  Titanium is a rare metal, but if this method is used, titanium in heterogeneous nuclei may be replaced by other elements, and it has become possible to provide a grain refiner that is not affected by the world situation. In addition, since the present invention makes it possible to freely use non-equilibrium heterogeneous nuclei, it can be applied to all structural metal materials such as iron-based and titanium-based materials as well as aluminum-based materials.

  The refinement ability depends on the number of heterogeneous nuclei in the grain refiner. According to the invention of Patent Document 1, the number of heterogeneous nuclei can be controlled by applying giant strain processing to the crystal grain refiner. Also in the present invention, this technique can be applied to put the crystal grain refining agent into practical use, and the number of heterogeneous nuclei can be controlled.

  According to the present invention, the strength of all cast materials can be improved, and thereby the fuel consumption can be improved through the weight reduction of the transport machine. Further, when used in a casting mold including foamed resin, the mold can be thinned, energy required for heating can be reduced, and generation of carbon dioxide can be suppressed.

Claims (9)

Particles, solid-like casting grain refining agent comprising dispersed in the matrix phase mainly composed of Al intermetallic compound represented by the formula (1) of the L1 ₂ structure.
(Al, Y) ₃ Z (1)
(Y is any one selected from Cu, Fe, Ni, Zn, Pd, Cr, Mn, Co, Ag, Rh, Pt, Au and Hf, and Z is selected from Ti, Zr and Zn. Any one being.)   The grain refiner for casting according to claim 1, wherein Z is Ti. The grain refiner for casting according to claim ₂ , wherein the intermetallic compound is Al ₅ CuTi ₂ . The grain refiner for casting according to claim 2, wherein the intermetallic compound is Al ₂₂ Fe ₃ Ti ₈ . The grain refiner for casting according to claim 2, wherein the intermetallic compound is Al ₆₇ Ni ₈ Ti ₂₅ .   The crystal grain refiner for casting according to any one of claims 1 to 5, wherein the particles have a volume fraction of 5 to 40% with respect to the whole crystal grain refiner. A method for producing a crystal grain refining agent for casting according to any one of claims 1 to 6,
A method for producing a crystal grain refining agent for casting, wherein the powder of the intermetallic compound and the powder of the matrix phase are mixed to form a compact, and then the compact is sintered by a discharge plasma sintering method. A method for producing a crystal grain refining agent for casting according to any one of claims 1 to 6,
A method for producing a crystal grain refining agent for casting, wherein the powder of the intermetallic compound and the powder of the matrix phase are mixed to form a compact, and then the compact is sintered to a semi-sintered state.   Manufacturing of a pure Al or Al alloy casting material, wherein the crystal grain refiner for casting according to any one of claims 1 to 6 is added to a molten pure Al or Al alloy, and the molten metal is poured into a mold. Method.