JP7333176B2 - Casting alloy, method for producing master alloy powder, and master alloy powder - Google Patents

Description

TECHNICAL FIELD The present invention relates to a casting alloy that can be used for preparing raw materials for powder metallurgy, a method for producing mother alloy powder, and a mother alloy powder.

Titanium alloys are widely used as materials for aerospace equipment because they are lightweight, have excellent corrosion resistance, and have high specific strength. In addition, titanium alloys have biocompatibility and are also used as materials for medical devices.
On the other hand, titanium alloys have difficulty in formability, and the melting and casting method requires many complicated steps until the final shape is obtained. This leads to an increase in manufacturing costs. In addition, the melting and casting method for titanium alloys is likely to cause segregation of alloying elements, and depending on the application, it may not be easy to satisfy the required properties.

On the other hand, in recent years, powder metallurgy methods, such as the raw powder mixing method, have attracted attention because they can obtain mechanical properties comparable to those of the melting and casting method at a relatively low cost. Generally, in the powder metallurgy method, a raw material powder adjusted to have a desired composition is molded, and if necessary, sintered or the like is performed, thereby easily obtaining a near-net-shape product. It should be noted that depending on the type of the product, the application, etc., the molded body may be distributed as it is without being sintered after molding.

Regarding the raw material powder used in this type of powder metallurgy method, Patent Document 1 describes "a master alloy for a sintered alloy having a composition of Ti-5Al-2.5Fe, in which the ratio of Al and Fe maintains a target ratio. To provide an alloy composition for a master alloy, which can be easily mixed in use, has good pulverization properties, and can easily obtain a powder of 150 μm or less, and Ti: 5 to 50 wt%. , Fe: 11 to 38 wt%, and the balance is Al containing unavoidable impurities”.

Patent Document 2 discloses "a Ti—Al intermetallic compound powder having excellent sinterability characterized by comprising 20 to 80 atomic % of Al, 0.5 to 10 atomic % of Fe, and the balance substantially consisting of Ti". are doing. According to this "Ti-Al intermetallic compound powder", "Since the range of the liquid phase that appears during sintering of the Ti-Al intermetallic compound powder compact becomes wider toward the low temperature side, sintering at a low temperature A product having a high sintered density can be obtained, and a high sintered density can be obtained even when a relatively coarse raw material powder is used. In addition, heat resistance, resistance to oxidation, abrasion resistance, etc. can be greatly improved."
In addition, Patent Document 2 discloses that "a raw material powder mixture blended so as to have a composition of 20 to 80 atomic % Al, 0.5 to 10 atomic % Fe, and the balance being substantially Ti is molded, and the molded body is made inert. A method for producing a high-density Ti—Al intermetallic compound sintered body characterized by heating in an atmosphere and sintering at a temperature range of 1100 to 1400° C.”.

JP-A-2-175831 JP-A-6-271901

By the way, titanium alloys containing Al and Fe, as described in Patent Documents 1 and 2, use so-called ubiquitous elements as alloying elements, so that products can be manufactured at low cost. Therefore, if such a Ti--Al--Fe alloy product can be produced by the powder metallurgy method without impairing the required properties, the production cost can be further reduced. In particular, the Ti-5Al-1Fe alloy containing about 5% by mass of Al and about 1% by mass of Fe is considered to be promising because it has almost the same level of mechanical properties as the Ti-6Al-4V alloy. .
Under such circumstances, it is desirable to establish a technology for manufacturing Ti--Al--Fe alloy products by powder metallurgy.

In the powder metallurgy method for Ti--Al--Fe alloys, alloying element powders such as pure Ti powders, and master alloy powders such as Ti--Al master alloy powders and Ti--Al--Fe master alloy powders can be used as raw material powders. However, it is preferable to use a Ti--Al--Fe mother alloy powder containing three elements from the viewpoint of suppressing the segregation of Al and Fe after sintering.

Such a Ti--Al--Fe master alloy powder can be produced by pulverizing a cast alloy such as an ingot by melting and casting.
Here, in order to suppress the segregation of Al and Fe by the powder metallurgy method of the Ti-Al-Fe alloy and to uniformly diffuse the alloy components thereof, when producing the Ti-Al-Fe mother alloy powder, the cast alloy is desired to be ground as finely as possible. This is because when coarse-grained master alloy powder is used and the diffusion of Al and Fe becomes insufficient, a state close to segregation may result. However, since Ti--Al--Fe alloys are generally poor in pulverizability, it has been difficult to refine the Ti--Al--Fe mother alloy powder.

With the "master alloy for sintered alloy" having the alloy composition described in Patent Document 1, it is difficult to say that a sufficiently fine master alloy powder can be easily produced by pulverization.
In Patent Document 2, what was actually produced as an example is an intermetallic compound obtained by burning and synthesizing powder having an atomic ratio of Ti and Al of substantially 1:1, and such an intermetallic compound was inferior in pulverizability. Further, in Patent Document 2, in order to obtain Ti--Al--Fe alloy powder, atomization is carried out after a predetermined powder is melted, which necessitates a relatively expensive atomization device, which unavoidably increases the cost. do not have.

An object of the present invention is to provide a casting alloy, a method for producing a mother alloy powder, and a mother alloy powder that can be favorably used for producing raw material powder for powder metallurgy of a Ti--Al--Fe alloy.

As a result of intensive studies, the inventors have found that a cast alloy having a predetermined composition and containing TiAl _(3-x) Fe _x has good pulverizability. New knowledge was obtained that it is easier to obtain The master alloy powder is particularly useful in the production of Ti-5Al-1Fe alloys.

Based on this knowledge, the casting alloy of the present invention contains 40% to 50% by mass of Ti and 8% to 10% by mass of Fe, with the balance being Al and unavoidable impurities, TiAl _{(3- x)} Fe _x (atomic number ratio x satisfies 0.1≦x≦0.4).

For the above cast alloy, the net intensity obtained by subtracting the background from the absolute value of the maximum intensity of the detected peak is multiplied by the half width of the detected peak in the X-ray diffraction result using CuKα rays using the diffractometer method. With respect to the peak area calculated by The peak area ratio of _(3-x) Fe _x {111} planes is preferably 0.10 or more.

A method for producing master alloy powder according to the present invention includes a pulverizing step of pulverizing any of the cast alloys described above.

The master alloy powder of the present invention contains TiAl _(3-x) Fe _x (atomic number ratio x satisfies 0.1≦x≦0.4) and has an oxygen content of 0.6% by mass or less. It is.

For the above mother alloy powder, the net intensity obtained by subtracting the background from the absolute value of the maximum intensity of the detected peak in the result of X-ray diffraction using CuKα rays using the diffractometer method, and the half width of the detected peak is added to the net intensity. For the peak area calculated by multiplying, 2θ exists in the range of 39.300° to 39.650° with respect to the sum of the peak areas of all detected peaks in the range of 2θ from 35° to 50° The peak area ratio of the TiAl _(3-x) Fe _x {111} plane is preferably 0.50 or more.

Further, it is preferable that the average particle diameter D50 of any one of the mother alloy powders described above is 20 μm or less.

In addition, the composition of any of the above master alloy powders contains 40% to 50% by mass of Ti, 8% to 10% by mass of Fe, 0.6% by mass or less of oxygen, and the balance is Al and unavoidable impurities.

According to the present invention, the cast alloy can be favorably used for producing raw material powder for powder metallurgy of a Ti--Al--Fe alloy.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.
(Casting alloy)
The casting alloy contains 40% to 50% by mass of Ti, 8% to 10% by mass of Fe, and the balance of Al and unavoidable impurities.

When the Ti content is out of the range of 40% by mass to 50% by mass, or when the Fe content is out of the range of 8% by mass to 10% by mass, TiAl _(3-x) Fe _x (0. 1≦x≦0.4) may not be obtained. Moreover, even if a cast alloy containing TiAl _(3-x) Fe _x (0.1≦x≦0.4) is obtained, the oxygen content of the master alloy powder produced by pulverizing it increases. obtain.

Specifically, when the Ti content is less than 40% by mass, Al, which is highly ductile, becomes excessive and the grindability of the cast alloy deteriorates. If the Ti content is more than 50% by mass, there is concern that a Ti- and Al-based compound that is difficult to pulverize will be produced and the pulverizability will deteriorate.
On the other hand, when the Fe content is less than 8% by mass, TiAl _(3-x) Fe _x (0.1≦x≦0.4) is produced, but the pulverizability becomes insufficient. If the Fe content is more than 10% by mass, the amount of TiAl _(3-x) Fe _x (0.1≦x≦0.4) produced is reduced, and there is a risk that the grindability will deteriorate.

From this point of view, the Ti content is preferably 40% to 48% by mass, more preferably 41% to 44% by mass. The Fe content is preferably 9% by mass to 10% by mass.

The Al content of the cast alloy can be 42% to 52% by mass, preferably 47% to 52% by mass, and more preferably 47% to 50% by mass.

Cast alloys may contain at least one element selected from the group consisting of Cu and O as unavoidable impurities. Incidentally, Cu may be contained in the cast alloy due to, for example, the material of the water-cooled crucible during melting. When such unavoidable impurities are included, the content of the unavoidable impurities is the total of them when multiple types are included, for example 0.01% by mass to 0.2% by mass, typically 0.05 % to 0.3% by mass.

The cast alloy contains an intermetallic compound of TiAl _(3-x) Fe _x . Here, x is the atomic number ratio and satisfies the relationship 0.1≦x≦0.4. By including TiAl _(3-x) Fe _x (0.1≦x≦0.4) in the casting alloy, the grindability is improved and it becomes easy to obtain fine mother alloy powder. Although the reason is not necessarily clear, TiAl _(3-x) Fe _x (0.1≦x≦0.4) is a very brittle TiAl ₃ in which part of Al is replaced with Fe. This is considered to be due to the fact that TiAl ₃ has the same degree of brittleness as TiAl 3 . However, the present invention is not limited to such reasons.
Therefore, cast alloys containing TiAl _(3-x) Fe _x (0.1≦x≦0.4) have excellent grindability and are suitable for producing master alloy powders. The mother alloy powder obtained by pulverizing it is advantageous for the production of titanium alloys such as Ti-5Al-1Fe alloy by powder metallurgy because of its Al and Fe content.

The presence or absence of TiAl _(3-x) Fe _x (0.1≦x≦0.4) can be confirmed as follows. An X-ray diffraction profile, which is the result of X-ray diffraction, is obtained from a sample taken from the cast alloy using an X-ray diffraction method. Then, the X-ray diffraction profile is subjected to necessary processing such as removal of peaks caused by Kα2 rays. After that, based on the PDF (Powder Diffraction File) of ICDD (International Center for Diffraction Data), within the range of 2θ = 39.300 ° to 39.650 °, the TiAl _(3-x) Fe _x {111} plane Check for the presence of detected peaks.

TiAl _(3-x) Fe _x (0.1≦x≦0.4) is preferably contained in the casting alloy in a predetermined amount or more. Specifically, in the above-described X-ray diffraction profile of the cast alloy, the sum of the peak areas of all detected peaks existing within the range of 2θ from 35 ° to 50 ° (also referred to as "sum of all peak areas") , the peak area of the TiAl _(3-x) Fe _x {111} plane present in the range of 39.300° to 39.650° 2θ (also referred to as “TiAl _(3-x) Fe _x peak area”). ) is preferably 0.10 or more.
This peak area is calculated by multiplying the net intensity obtained by subtracting the background from the absolute value of the maximum intensity of the detected peak by the half width of the detected peak. Here, the background is obtained by the Sonneveld-Visser method. The half width of the detected peak means the width at half the net intensity in the chevron detected peak.

TiAl _(3-x) Fe _x peak within the range of 2θ = 39.300° to 39.650° relative to the sum of all peak areas (A) within the range of 2θ = 35° to 50° in the X-ray diffraction profile If the area (B) ratio (B/A) is less than 0.10, there is concern that the pulverizability will be insufficient. Further, in this case, the oxygen content of the master alloy powder produced by pulverizing the cast alloy may not be reduced as much as expected. From this point of view, the ratio of the TiAl _(3-x) Fe _x peak area to the total peak area is preferably 0.30 or more.
Although it is desirable that the ratio of the TiAl _(3-x) Fe _x peak area to the total peak area is as large as possible, it may be, for example, 0.60 or less.

The cast alloy as described above can be produced by melting and casting raw materials blended so as to have a predetermined composition in an arc melting furnace or the like. Here, it is important to set at least the target composition to Ti: 40% by mass to 50% by mass and Fe: 8% by mass to 10% by mass, as described above. As will be understood from the test results described later, if the Ti and Fe contents deviate even slightly from this range, the constituent phases of the cast alloy may change significantly.

Further, it is preferable to prepare pure metal raw materials of Ti, Al, and Fe, respectively, and arrange them in layers in the melting furnace in order from the pure metal raw materials having the lightest specific gravities. Specifically, a pure Al raw material, a pure Ti raw material, and a pure Fe raw material are arranged in this order from the bottom. Thereby, the separation of the molten metal can be prevented.
Further, in order to prevent segregation in the cast alloy, it is preferable to reverse the ingot a plurality of times, such as turning the ingot upside down after a predetermined melting treatment and performing the melting treatment again.
It is believed that these factors can influence the formation of TiAl _(3-x) Fe _x (0.1≦x≦0.4) and the increase in its content in cast alloys.

(Manufacturing method of mother alloy powder)
The method of producing the master alloy powder from the cast alloy described above includes a pulverization step of pulverizing the cast alloy. There is also an atomization method for producing powder, but in this embodiment, the mother alloy powder can be produced by a simple process of pulverization without using expensive equipment.

Various pulverization methods can be employed in the pulverization step. Specific examples of the pulverizing method include using a ball mill or a pulverizing rotor, and utilizing collision between particles due to ejection of high-pressure gas.

When the mother alloy powder is used in the powder metallurgy method, the mother alloy powder is preferably fine from the viewpoint of suppressing segregation and improving the density.
In order to obtain a fine master alloy powder, a classification step for obtaining particles having a small particle size can be performed after the pulverization step, if necessary. In the classification step, dry classification using an air stream is possible, or sieving using a sieve may be used. In addition, when sieving with a sieve in this classification step, it is preferable to perform a plurality of stages of sieving using a plurality of sieves having different mesh openings.

In producing the master alloy powder, prior to the pulverization step, if necessary, a method of estimating the pulverizability of the alloy material such as cast alloy to be pulverized can be carried out. Then, it is preferable to determine whether or not to perform the pulverization process for the alloy material according to the pulverizability estimated thereby. If the pulverizability estimated here is good, fine mother alloy powder can be easily produced, and a final product with little segregation can be produced by powder metallurgy. On the other hand, if the estimated crushability is not good, for example, the cast alloy or the like can be melted again without performing the crushing step.

The method for estimating the crushability of such an alloy material includes an analysis step of performing X-ray diffraction on an alloy material containing Ti, Fe and Al, and the X-ray diffraction result obtained by the analysis, TiAl _{(3 -x)} determining the presence or absence of Fe _x (0.1≦x≦0.4).

In the analysis step, the alloy material is subjected to X-ray diffraction with CuKα rays using the diffractometer method under the same conditions as described above, and an X-ray diffraction profile is obtained as the X-ray diffraction result. can be done.
In the subsequent determination step, in the X-ray diffraction profile, as also described above, within the range of 2θ = 39.300° to 39.650°, the detected peak of the TiAl _(3-x) Fe _x {111} plane By confirming the presence or absence of TiAl(3-x)Fex (atomic number ratio x satisfies 0.1≦x≦0.4) in the alloy material, the presence or absence of TiAl(3-x)Fex is confirmed.

In the determination step, regarding the above-mentioned peak areas in the X-ray diffraction profile, 2θ is 39.300° to 39.650° with respect to the sum of the peak areas of all detected peaks existing within the range of 2θ from 35° to 50°. It is preferable to calculate the ratio of the peak areas of TiAl _(3-x) Fe _x {111} planes present within the range of .
Then, if the ratio of the TiAl _(3-x) Fe _x peak area to the total peak area is 0.10 or more, it can be sufficiently finely refined by the predetermined pulverization in the pulverization process, and the fine master alloy powder can be obtained at a high It is thought that it can be obtained by the recovery rate. It is preferable to use such a ratio of peak areas as at least one criterion for estimating crushability and the like.

(Mother alloy powder)
The master alloy powder produced as described above contains Ti, Al and Fe, and contains an intermetallic compound of TiAl _(3-x) Fe _x (0.1≦x≦0.4).
In particular, intermetallic compounds other than TiAl _(3-x) Fe _x (0.1 ≤ x ≤ 0.4), which have good grindability and are easily pulverized by going through the above pulverization process and classification process. is removed, the proportion of TiAl _(3-x) Fe _x (0.1≦x≦0.4) may be increased in the master alloy powder. As a result, it is desirable to achieve a reduction in the oxygen content of the master alloy powder, thereby ensuring the required ductility of the final titanium alloy product produced by powder metallurgy. Also, from the content ratio of Al and Fe contained in the mother alloy powder, the mother alloy powder containing TiAl _(3-x) Fe _x (0.1≦x≦0.4) is Ti-5Al- It is advantageous for the production of titanium alloys such as 1Fe alloys.

More specifically, for the master alloy powder, in the X-ray diffraction profile, 2θ is The ratio of the peak areas of the TiAl _(3-x) Fe _x {111} planes present in the range of 39.300° to 39.650° (TiAl _(3-x) Fe _x peak areas) is preferably 0. 50 or more, more preferably 0.60 or more. In master alloy powders, the ratio of TiAl _(3-x) Fe _x peak areas to the sum of all peak areas can be, for example, 0.90 or less. In polycrystals, even for a single compound, several peaks are detected depending on the plane orientation. Since the area of one of these peaks is used as an index here, the area ratio is usually smaller than 1.00.
The presence or absence of TiAl _(3-x) Fe _x (0.1≦x≦0.4) in the master alloy powder and the ratio of the peak areas are also confirmed or measured in the same manner as described above for the cast alloy.

In this case, the oxygen content of the master alloy powder may be 0.6% by mass or less, or even 0.5% by mass or less. Such a low oxygen content of the mother alloy powder is suitable for producing titanium alloy products by powder metallurgy using the mother alloy powder. The ductility of titanium alloy products is greatly affected by the oxygen content. By using master alloy powder with a low oxygen content, it becomes easier to ensure the required ductility of the product. The oxygen content of the master alloy powder may be, for example, 0.1% by mass or more, typically 0.3% by mass or more.
The oxygen content of the master alloy powder can be measured by an infrared absorption method.

Also, the average particle diameter D50 of the mother alloy powder is preferably 20 μm or less. This is because such a fine master alloy powder suppresses the segregation of Al and Fe in a product manufactured using the powder metallurgy method, and causes them to diffuse sufficiently in Ti. From this point of view, the average particle size D50 of the mother alloy powder is more preferably 15 μm or less. The average particle diameter D50 of the mother alloy powder may be, for example, 7 μm or more, typically 10 μm or more.

This average particle diameter D50 can also be referred to as the median diameter. The average particle size D50 of the mother alloy powder is obtained by determining the particle size at which the volume-based frequency accumulation is 50% in the particle size distribution graph obtained by measurement with a laser diffraction/scattering particle size distribution measuring device. .

The mother alloy powder may contain Ti in an amount of, for example, 40% to 50%, 40% to 48%, 41% to 44% by mass. Further, Fe may be contained, for example, 8% to 10% by mass, 9% to 10% by mass. Also, Al may be contained, for example, in an amount of 41% to 51%, 46% to 51%, 46% to 49% by mass.
and
Additionally, the master alloy powder may contain the aforementioned impurities that may be included in the cast alloy.

The mother alloy powder described above is optionally mixed with pure titanium powder and/or powder made of an alloy element other than Al and Fe to produce a Ti-5Al-1Fe alloy by a powder metallurgy method. -5Al-1Fe-x alloy, which has 5 mass% Al and 1 mass% Fe, and can be suitably used for producing a titanium alloy containing third and fourth alloy components. Here, the powder composed of elements other than Al and Fe refers to alloying elements used in general titanium alloys, such as V, Cr, Mn, Sn, Zr, Si, or ceramic powders, or mothers of target components. Although it refers to alloy powder, it is not limited to the above elements.

Next, the present invention was implemented on a trial basis, and its effects were confirmed, which will be described below. However, the description herein is for illustrative purposes only and is not intended to be limiting.

A pure Fe raw material, a pure Al raw material, and a pure Fe raw material were weighed using an electronic balance, and then placed in a melting furnace in layers in order from the pure metal raw material having the lowest specific gravity. Specifically, a pure Al raw material, a pure Ti raw material, and a pure Fe raw material were arranged in this order from the bottom, and arc melting was performed on these raw materials. After the first melting, the ingot was turned upside down to perform the second melting, thereby producing a button ingot with dimensions of about φ50×7 mmt and a mass of about 50 g.

By this method, button ingots of Test Examples 1 to 8, as shown in Table 1, were obtained under the same production conditions other than the composition. The component values of Ti, Al, and Fe in each button ingot were measured by inductively coupled plasma optical emission spectrometry (ICP-OES) using SPS-3100 manufactured by Hitachi High-Tech Science Co., Ltd. The balance of the ingot components other than Ti and Fe was mostly Al.

A part of each ingot was sampled, and a sample sliced to a thickness of 1 mm was analyzed by X-ray diffraction. Here, X'pert-PRO-MPD manufactured by PANalytical was used as an X-ray diffractometer, and X-rays were CuKα rays. From the X-ray diffraction profile thus obtained, it was confirmed that the main constituent phases of the ingot were confirmed, and when TiAl _(3-x) Fe _x (0.1 ≤ x ≤ 0.4) was present, 2θ The ratio of the TiAl _(3-x) Fe _x peak area to the sum of all peak areas present within a range of ° was calculated. In Table 1, the ratio of the TiAl _{(3-x) Fe x} peak area to the sum of all peak areas present in the button ingot _with 2θ within the range of 35° to 50° is Shown as a ratio.

Next, each of the button ingots was crushed using a press (maximum load of 20 tons), and then sieved with a sieve having an opening of about 5 mm. After that, the under-sieving (about 350 g) of the sieving is put into a SUS ball mill container together with SUS balls for pulverization (φ 10 mm, 10 kg), and the inside of the container is replaced with argon gas three times to remove the under-sieving. pulverized. As grinding conditions, the rotation speed of the ball mill container was 84 rpm, and the grinding time was 20 hours. After that, the powder obtained by pulverization was sieved successively with a sieve with a mesh size of 150 μm and a sieve with a mesh size of 45 μm to obtain under-sieved master alloy powder.

For Test Examples 1 to 4, inductively coupled plasma-optical emission spectroscopy (ICP-OES) was performed on the above mother alloy powders using the same equipment as above to measure the contents of Ti, Al, and Fe. The oxygen content was measured by an infrared absorption method using a TCH-600 model manufactured by the company. In addition, the particle size distribution was measured by a laser diffraction/scattering method using LA-920 manufactured by Horiba, Ltd., and the constituent phases were analyzed by X-ray diffraction. Those results are shown in Table 1. The content ratio of TiAl _(3-x) Fe _x in the master alloy powder in Table 1 is the TiAl _(3-x) Fe _x peak area with respect to the sum of all peak areas within the range of 2θ of 35° to 50° in the master alloy powder. is the ratio of In Table 1, the mother alloy powder yield means the ratio of the mass under sieving of 45 μm to the mass put into the ball mill container. A yield of 40% or more was judged to be good.

For Test Examples 5 and 6, in which pulverization was not possible, and Test Examples 7 and 8, in which the yield of the mother alloy powder was low, the mother alloy powder was not analyzed.

As shown in Table 1, button ingots of Test Examples 1 and 2 containing TiAl _(3-x) Fe _x (0.1≦x≦0.4) with Ti and Fe contents within predetermined ranges, respectively was cast with a predetermined composition under predetermined conditions, and had good grindability.

Moreover, in Test Examples 1 and 2, since the pulverizability was good, fine master alloy powders having an average particle diameter D50 of 20 μm or less were obtained at a high yield. In Test Example 3, although the yield of the mother alloy powder was good, the oxygen content was as high as over 0.6% by mass. In Test Example 4, not only was the yield insufficient, but the average particle diameter D50 of the powder exceeded 20 μm.

It can be seen that when the TiAl _(3-x) Fe _x content ratio of the mother alloy powder is high, the oxygen content is well reduced.

As described above, according to the present invention, it has been found that the cast alloy can be favorably used for producing the raw material powder for the powder metallurgy method of the Ti--Al--Fe alloy.

Claims (6)

It contains 40% to 50% by mass of Ti and 8% to 10% by mass of Fe, with the balance being Al and unavoidable impurities, TiAl _(3-x) Fe _x (atomic ratio x is 0.00). 1≦x≦0.4). The peak area calculated by multiplying the net intensity obtained by subtracting the background from the absolute value of the maximum intensity of the detected peak in the result of X-ray diffraction using CuKα rays using the diffractometer method by the half width of the detected peak. about,
TiAl _(3-x) Fe _x { 2. The casting alloy according to claim 1, wherein the peak area ratio of the 111} planes is 0.10 or more. A method for producing a mother alloy powder, comprising a pulverizing step of pulverizing the cast alloy according to claim 1 or 2. TiAl _(3-x) Fe _x (atomic number ratio x satisfies 0.1 ≤ x ≤ 0.4),
A master alloy powder containing 40% to 50% by mass of Ti, 8% to 10% by mass of Fe, 0.6% by mass or less of oxygen, and the balance being Al and unavoidable impurities. The peak area calculated by multiplying the net intensity obtained by subtracting the background from the absolute value of the maximum intensity of the detected peak in the result of X-ray diffraction using CuKα rays using the diffractometer method by the half width of the detected peak. about,
TiAl _(3-x) Fe _x { 5. The mother alloy powder according to claim 4, wherein the peak area ratio of the 111} plane is 0.50 or more. 6. The mother alloy powder according to claim 4 or 5, having an average particle diameter D50 of 20 μm or less.