WO2016035824A1 - METHOD FOR DEOXIDIZING Ti-Al ALLOY - Google Patents

Abstract

　A Ti-Al alloy having an Al content of at least 40% by mass, said alloy being produced using an alloy material comprising a titanium material and an aluminum material and having a total oxygen content of at least 0.1% by mass, is melted and held in an atmosphere of at least 1.33 Pa according to a melting process incorporating a water-cooled copper vessel, thereby reducing the oxygen content of the Ti-Al based alloy.

Description

Deoxidation method for Ti-Al alloys

The present invention relates to a method for deoxidizing a Ti—Al based alloy that removes oxygen from a Ti—Al based alloy made using an alloy material comprising a titanium material and an aluminum material and containing a total of 0.1 mass% or more of oxygen. It is about.

In recent years, demand for Ti-Al alloys as metal materials for aircraft and automobiles is increasing. When manufacturing such a titanium alloy such as a Ti—Al alloy mainly composed of active metal titanium, it is necessary to prevent contamination by oxygen during melting. Conventionally, vacuum arc melting (VAR), Melting methods such as electron beam melting (EB), plasma arc melting (PAM), vacuum induction melting (VIM), and water-cooled copper induction melting (CCIM) have been adopted.

Among the above-described melting methods, melting methods such as VAR, EB, and VIM are melting methods in which an alloy is melted in a vacuum atmosphere. When such a melting method is used for melting a Ti—Al based alloy, Not only Al, which is an element, but also Ti volatilizes during melting, causing loss. In other words, in an industrial process, it is extremely difficult to control the Ti—Al-based alloy to a target composition, and as a result, the manufacturing cost is increased.

In addition, in order to produce a Ti—Al alloy having a low oxygen content, it is effective to produce a Ti—Al alloy using a high quality titanium material having a low oxygen content. Titanium materials are expensive and have a tendency to soar in recent years, so the oxygen content is higher than high-grade titanium materials, but cheap sponge titanium, scrap raw materials, rutile ore (TiO ₂ ), etc. There is a growing need to produce Ti-Al alloys using low-grade titanium materials.

Since Ti is an active metal and has a very strong binding force with impurities, especially oxygen, present in the melting atmosphere, measures have been conventionally taken to reduce oxygen taken from the outside during melting and prevent contamination. It was. However, it is not easy to remove oxygen once dissolved in Ti, and the efforts themselves are few at present, but there are proposals as shown below as prior art.

Patent Document 1 discloses a method for producing a low-oxygen Ti—Al-based alloy and an invention relating to a low-oxygen Ti—Al-based alloy. In paragraph [0013], the paragraph [0013] describes “1 × 10 ⁻² Torr than When Al is forcibly removed in a high vacuum atmosphere, the amount of oxygen in the molten metal is reduced accordingly, and the Al is forced from the molten metal having a composition containing more Al than the Al content of the final target composition. By removing this, it is possible to produce a Ti—Al-based alloy having the final target composition and at the same time reduce oxygen to 200 ppm or less. ”

In other words, the method for producing a low oxygen Ti—Al alloy described in Patent Document 1 uses a low oxygen Ti—Al alloy in a high vacuum atmosphere at a pressure lower than 1.33 Pa (1 × 10 ⁻² Torr). Such melting in a high vacuum atmosphere causes volatilization loss not only for the alloy element Al but also for Ti, which is an effective method for producing a low oxygen Ti—Al alloy. Although this method can be said to be a method, it is necessary to add extra Ti and Al, and there is a concern about an increase in manufacturing cost.

Patent Document 2 discloses an invention relating to a low-oxygen Ti—Al-based alloy and a method for producing the same, and its paragraph [0010] states that “the present invention is made to solve the above-mentioned problems. In high-purity, low-oxygen Ti-Al alloy by deoxidizing with Ca, evaporating and removing excess Ca, and contamination-free uniform dissolution And an object thereof is to provide a manufacturing method thereof ”.

Although this method can be said to be an effective method for producing a low-oxygen Ti—Al-based alloy, it is a method that undergoes a plurality of steps of metal Ca addition dissolution, metal Ca removal, and melting for homogenization. In addition, since the metal Ca is dissolved in titanium, it is difficult to completely remove the residual Ca. Therefore, the manufacturing cost and the manufacturing time are increased, and the Ti—Al based alloy due to the residual Ca that cannot be completely removed. This is a method of concern for contamination and changes in various properties.

Patent Document 3 discloses an invention relating to a method for producing a TiAl-based alloy ingot, and paragraph [0017] describes that the oxygen content can be reduced in all regions of the ingot. In addition, the claim 1 states that “the oxygen content of the Ti raw material is 800 ppm or less, the oxygen content of the Al raw material is 100 ppm or less, and when the other alloy components are Cr, V, Nb, the oxygen content thereof. The method for producing an ingot of a TiAl-based alloy characterized in that when the amount is 2000 ppm or less and the other alloy component is Mn, its oxygen content is 3000 ppm or less.

Thus, it can be said that the ingot manufacturing method of the TiAl-based alloy described in Patent Document 3 is an effective method that can reduce the oxygen content of the ingot, but this method is a high-quality low oxygen content. This method is to obtain a TiAl-based alloy having a low oxygen content using a simple material, and is not a method using a low-grade Ti material having a relatively high oxygen content. In the examples, only a TiAl alloy having a low Al content of 30% by mass is described.

Patent Document 4 discloses an invention relating to a casting method of a titanium-aluminum alloy casting, in which sponge titanium as a raw material is melted, and aluminum as a raw material is added to the molten titanium. It is described that a titanium-aluminum alloy containing a fixed amount of titanium and aluminum is prepared, and in claim 2 and paragraph [0020], the oxygen content of the sponge titanium is 350 ppm or less, and In the examples, it is described that the oxygen content of titanium sponge is 0.03 wt%.

As described above, in the casting method of the titanium-aluminum alloy casting described in Patent Document 4, high-quality sponge titanium having an oxygen content of 350 ppm or less (corresponding to 0.035% by mass or less) is used as a raw material. In this method, a high-grade material with a low oxygen content is used to obtain a cast titanium-aluminum alloy with a low oxygen content. A low-grade titanium material with a relatively high oxygen content is used. Not a way. In the examples, only a titanium-aluminum alloy casting having a low Al content of 34% by mass is described.

Japanese Laid-Open Patent Publication No. 5-59466 Japanese Patent Laid-Open No. 5-140669 Japanese Unexamined Patent Publication No. 2009-1113060 Japanese Patent Laid-Open No. 5-154642

The present invention has been made in order to solve the above-mentioned conventional problems. A low-grade titanium material having a high oxygen content is used to form a Ti-Al alloy having a target composition and a low oxygen content with a high vacuum. It is an object of the present invention to provide a method for deoxidizing a Ti—Al based alloy that can be easily manufactured without using an atmosphere.

The Ti—Al-based alloy deoxidation method of the present invention contains 40 mass% or more of Al produced using an alloy material made of a titanium material and an aluminum material and containing 0.1 mass% or more of oxygen in total. The Ti—Al-based alloy is melted and held by a melting method using a water-cooled copper container in an atmosphere of 1.33 Pa or higher, thereby reducing the oxygen content of the Ti—Al-based alloy. To do.

Further, before or during melting of the Ti—Al alloy, it is preferable to add CaO—CaF ₂ flux in which 35 to 95 mass% of calcium fluoride is mixed with calcium oxide.

Further, the melting method using the water-cooled copper container is preferably any one of an arc melting method, a plasma arc melting method, and an induction melting method.

According to the Ti—Al-based alloy deoxidation method of the present invention, a low-quality and inexpensive titanium material having an oxygen content of 0.1 mass% or more is used, and the volatilization loss of Al and Ti is small (substantially) A Ti—Al alloy having a target composition and a low oxygen content can be easily produced without a high vacuum atmosphere (without reduction).

In addition, if the Ti content obtained by the deoxidation method of the Ti—Al based alloy of the present invention is 40% by mass or more and the Ti—Al based alloy having a small oxygen content is diluted with low oxygen titanium, the Al content is obtained. It is possible to manufacture a Ti—Al alloy having a low oxygen content of less than 40% by mass relatively easily and inexpensively.

It is a graph which shows the relationship between Al content and oxygen content in the Ti-Al type alloy after melt | dissolution. Is a graph showing the relationship between the oxygen content of Ti-Al-based alloy after dissolution and the amount of calcium fluoride CaO-CaF ₂ in the flux. It is a graph which shows the relationship between the melting time of a Ti-Al type alloy sample, and the mass change rate before and behind melting. It is a graph which shows the relationship between Al content of a Ti-Al type-alloy sample, and the mass change rate before and behind melt | dissolution. It is a graph which shows the maximum oxygen amount which dissolves in a Ti-Al type alloy.

The inventors use low-grade titanium materials containing a large amount of oxygen such as low-grade sponge titanium, scrap raw materials, and rutile ore (TiO ₂ ), so that the volatilization loss of Al and Ti is small (substantially) In order to find a method that can easily produce a Ti—Al-based alloy having a target composition and low oxygen content without using a high-vacuum atmosphere (without reduction), intensive studies were conducted.

The maximum amount of oxygen dissolved in the Ti-Al alloy is X. L. Li, R.R. Hillel, F.M. Teyssandier, S .; K. Choi, and F. J. et al. J. et al. Van. Loo, Acta Metall. Mater. , 40 {11} 3147-3157 (1992), it is assumed that the relation shown by the broken line in FIG. 5 is obtained. From this fact, the present inventors have focused on the fact that the Ti—Al alloy containing a high concentration of Al has a low solid solution oxygen concentration. As a result, even a Ti—Al alloy produced using a low-grade titanium material can be a water-cooled copper container even in a high vacuum atmosphere as long as it is a Ti—Al alloy containing 40% by mass or more of Al. It has been found that deoxidation reaction can proceed by dissolution using Al, Ti and Al volatilization loss is small (substantially without reduction), and low oxygen Ti-Al alloys with the target composition can be easily produced. The present invention has been completed.

Further, as a result of further investigation, by adding a CaO—CaF ₂ flux having a specific component composition not dissolved in titanium as a deoxidation reaction accelerator before or during melting of the Ti—Al-based alloy, The present inventors also found that the deoxidation reaction proceeds more reliably. Incidentally, in the deoxidation reaction by adding CaO—CaF ₂ flux to the Ti—Al alloy, Al ₂ O ₃ which is a deoxidation product of the Ti—Al alloy is dissolved in the added CaO—CaF ₂ flux. The melting point of the CaO—CaF ₂ flux needs to be approximately 1800 K or less, which is estimated as the melting temperature of the Ti—Al alloy.

Hereinafter, the present invention will be described in more detail based on embodiments.

The Ti—Al-based alloy deoxidation method of the present invention contains 40 mass% or more of Al produced using an alloy material made of a titanium material and an aluminum material and containing 0.1 mass% or more of oxygen in total. The Ti—Al-based alloy is melted and held in an atmosphere of 1.33 Pa or more by a melting method such as an arc melting method using a water-cooled copper container, a plasma arc melting method, an induction melting method, etc. In this method, the oxygen content of the Al alloy is reduced, and as the titanium material, low-grade sponge titanium, scrap raw material, rutile ore (TiO ₂ ), or the like is used.

The reason for using titanium materials with high oxygen content, such as low-grade sponge titanium, scrap raw materials, and rutile ore (TiO ₂ ), for the production of Ti—Al alloys is because these titanium materials are inexpensive and easy to procure. It is. The total oxygen content of the alloy material composed of these titanium material and aluminum material is set to 0.1 mass% or more if the total oxygen content in the alloy material is less than 0.1 mass%. This is because the content is small and deoxidation itself is not necessary. In the present invention, the upper limit of the oxygen content is not specified, but the upper limit of the total content of oxygen actually contained in the alloy material is considered to be about 25.0% by mass.

The reason why the Al content of the Ti—Al based alloy produced using the alloy material made of the titanium material and the aluminum material is 40% by mass or more is that the Al content in the Ti—Al based alloy is 40% by mass. If it is above, even in an atmosphere of 1.33 Pa or higher, not in a high vacuum atmosphere, by a melting method such as an arc melting method, a plasma arc melting method, an induction melting method using a water-cooled copper container, Ti This is because the deoxidation reaction of the Al-based alloy proceeds. This deoxidation reaction is a phenomenon that occurs when the concentration of solid solution oxygen in a Ti—Al alloy having a high Al content decreases and supersaturated oxygen combines with Al to form Al ₂ O ₃ . That is, oxygen is discharged from the Ti—Al alloy in the form of Al ₂ O ₃ . When the Al content of the Ti—Al alloy is 40% by mass or more, the deoxidation reaction proceeds at a temperature of approximately 1800 K or more at which the Ti—Al alloy is dissolved.

In the present invention, the upper limit of the Al content of a Ti—Al alloy produced using an alloy material such as a titanium material and an aluminum material is not particularly specified, but the preferable upper limit is 70% by mass, more preferably 60% by mass. %, More preferably 50% by mass. Ti-Al alloys contain other alloy elements other than Al and impurities such as oxygen. Therefore, if the content of Al, which is an alloy element, increases too much, the proportion of Ti decreases and the Ti-Al alloy is called an alloy. become unable. Moreover, although it was set as the atmosphere of 1.33 Pa or more and the upper limit was not prescribed | regulated, it can be assumed that an actual upper limit is about 5.33 * 10 < ⁵ > Pa. Moreover, the minimum with preferable atmospheric pressure is 10 Pa, More preferably, it is 1.0 * 10 < ² > Pa, From the ease of atmospheric control etc., it is especially preferable to set it as 1.0 * 10 < ⁴ > Pa or more.

In addition, when deoxidizing a Ti—Al alloy, a deoxidation reaction can be more reliably advanced by adding a flux as a deoxidation reaction accelerator before or during the dissolution of the Ti—Al alloy. Can do. The flux added as a deoxidation reaction accelerator to the Ti—Al based alloy must be a low melting point flux having a melting point lower than the melting temperature of the Ti—Al based alloy. The CaO—CaF ₂ flux, which is considered to be most preferable from the viewpoint of cost, was adopted.

In producing a Ti—Al based alloy having a low oxygen content, the deoxidation reaction is further promoted by adding this CaO—CaF ₂ flux to the Ti—Al based alloy. _The deoxidation reaction is not accelerated unless the melting point of the _two fluxes is about 1800 K or less, which is the melting temperature of the Ti—Al alloy. The reason why the deoxidation reaction is promoted by the addition of the flux is that Al ₂ O ₃ produced by the deoxidation reaction is absorbed in the flux, so that the activity of Al ₂ O ₃ is reduced, and the oxygen concentration is accordingly reduced. This is because of a decrease.

The Al deoxidation reaction can be represented by the following formula (1), and the reaction constant can be represented by the formula (2). Under the Al / Al ₂ O ₃ equilibrium state in which the present deoxidation reaction is expressed, K in the formula (2) is constant, but since there is almost no change in aAl due to the deoxidation reaction, aAl in the following formula (2) _{When 2} O ₃ decreases (approaching zero as much as it is absorbed in the flux), PO ₂ (containing oxygen concentration) in formula (2) also decreases accordingly.
2Al (inAl) + 3 / 2O ₂ (inTi-Al) = Al ₂ O ₃ Formula (1)
K = aAl ₂ O ₃ / (aAl ² · PO ₂ ^3/2 ) Formula (2)

CaO-CaF ₂ When the amount of calcium fluoride flux is less than 35% by weight, exceeds the CaO-CaF ₂ flux melting point of 1800 K, a promoting effect of deoxidation reaction with CaO-CaF ₂ flux added Can't get. On the other hand, when the blending amount of calcium fluoride exceeds 95% by mass, contamination with fluorine occurs. Therefore, in the present invention, CaO—CaF ₂ flux in which 35 to 95 mass% of calcium fluoride is mixed with calcium oxide is added. A more preferable blending amount of calcium fluoride in the CaO—CaF ₂ flux is 60 to 90% by mass. The addition amount of the CaO—CaF ₂ flux is preferably 5 to 20% by mass with respect to the mass of the Ti—Al alloy.

The Ti—Al-based alloy deoxidation method of the present invention is a method of reducing the oxygen content by reducing the Al and Ti volatilization loss of the Ti—Al-based alloy (without substantially reducing it). Although demonstrated, the fall rate of content of Al and Ti which can be accept | permitted substantially is 5.0% or less. That is, substantially means 5.0% or less.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, and the present invention is implemented with appropriate modifications within a range that can meet the gist of the present invention. These are all included in the technical scope of the present invention.

(Relation between Al content in Ti-Al alloy and oxygen content after dissolution)
・ Plasma arc melting method, no flux addition
Deoxidation of a Ti—Al alloy having an oxygen content of 0.8 mass%, prepared using an alloy material composed of a titanium material and an aluminum material, was melted in a 100 kW plasma arc furnace using a water-cooled copper container, and thereafter It was carried out by holding. In order to investigate the influence of the Al content of the Ti—Al based alloy on the deoxidation reaction due to dissolution, the Al content is 10% by mass, 20% by mass, 30% by mass, 40% by mass, 50% by mass, and 60% by mass. Samples prepared using Ti-Al alloys were prepared. Each sample was 100 g, only Ar was used as the plasma gas, and the pressure during dissolution was 1.20 × 10 ⁵ Pa. FIG. 1 shows the relationship between the Al concentration (Al content) in the Ti—Al-based alloy after melting and holding using a 100 kW plasma arc furnace and the oxygen concentration (oxygen content) after melting.

According to FIG. 1, the oxygen content after dissolution of a Ti—Al alloy having an Al content of 10 to 30% by mass does not change around 0.8% by mass, but the Al content is 40% by mass or more. It can be seen that in the Ti—Al alloy, the oxygen content decreases after melting. From this result, it can be seen that when the Al content of the Ti—Al-based alloy is 40% by mass or more, the deoxidation reaction proceeds by dissolution.

・ Plasma arc melting method, flux added
In addition, for a Ti—Al based alloy having an oxygen content of 30% by mass, 40% by mass, and 60% by mass with reduced oxygen content after dissolution in the above test, acceleration of deoxidation reaction by addition of CaO—CaF ₂ flux In order to investigate this situation, the Ti—Al alloy was deoxidized by plasma arc melting under exactly the same conditions as when no flux was added except for the addition of CaO—CaF ₂ flux. The amount of calcium fluoride in the CaO—CaF ₂ flux was 80% by mass, and the amount of CaO—CaF ₂ flux added was 5 g. The results are shown in FIG.

According to FIG. 1, the case of adding CaO-CaF ₂ flux, Al content of 40 mass%, in either case of 60 mass percent, compared to the case without the addition of CaO-CaF ₂ flux, further deoxidation It can be seen that is promoted. Incidentally, the oxygen content in the Ti-Al alloy after melting (mass ratio, hereinafter all oxygen contents are shown by mass ratio) is the case where the Al content is 40% by mass and the CaO-CaF ₂ flux is added. not when the 5400Ppm, is 2400ppm is upon addition of CaO-CaF ₂ flux, and in case the Al content is 60 wt%, when no addition of CaO-CaF ₂ flux 280 ppm, a CaO-CaF ₂ flux When added, it is 220 ppm.

・ When titanium oxide material is used as titanium material
In addition, a 100 kW plasma arc furnace using a water-cooled copper vessel was used for the deoxidation of a Ti—Al alloy having an oxygen content of 16.3% by mass, which was separately produced using an alloy material made of a titanium oxide material and an aluminum material. It was carried out by dissolving in and then holding. At this time, the Al content of the Ti—Al-based alloy was set to 60% by mass, and both the case where the CaO—CaF ₂ flux was added and the case where it was not added were carried out. Note that only Ar is used as the plasma gas, the pressure during dissolution is 1.20 × 10 ⁵ Pa, the amount of calcium fluoride in the CaO—CaF ₂ flux is 80% by mass, and the amount of CaO—CaF ₂ flux added Was 5 g.

The oxygen content in the Ti—Al based alloy after melting and holding is about 540 ppm when no CaO—CaF ₂ flux is added, and the oxygen content exceeds 10 mass% using titanium oxide as a raw material. Even with such a material, the deoxidation effect was considerably exhibited. When the CaO—CaF ₂ flux was added, the oxygen content in the Ti—Al based alloy was about 330 ppm, and it was confirmed that the deoxidation effect was further exhibited by adding the flux.

・ Induction melting method, no flux added
Further, in place of the plasma arc melting method, an induction melting method using a water-cooled copper container is adopted, and deoxidation from a Ti—Al alloy having an oxygen content of 0.8% by mass is performed in the same manner as the plasma arc melting method. The test was conducted. In order to investigate the influence of the Al content of the Ti—Al based alloy on the deoxidation reaction, Ti—Al based alloys having an Al content of 37 mass%, 39 mass%, and 51 mass% were respectively melted. In each dissolution, the dissolution amount was 20 kg, the atmosphere in the dissolution chamber was Ar, and the pressure during dissolution was 7.0 × 10 ⁴ Pa. Data on the relationship between Al concentration (Al content) and oxygen concentration (oxygen content) in Ti-Al alloys after melting and holding using an induction melting furnace when using plasma arc melting method Together with FIG.

According to FIG. 1, it can be seen that the oxygen content after melting decreases from the point where the Al content exceeds 40% by mass, as in the case where the plasma arc melting method is adopted. From this result, it can be seen that in the case of the induction melting method, as in the plasma arc melting method, the deoxidation reaction proceeds by dissolution when the Al content of the Ti—Al-based alloy is 40% by mass or more.

・ Induction melting method, with flux added
In order to investigate the progress of deoxidation reaction by adding CaO-CaF ₂ flux for Ti-Al alloys with Al content of 40 mass%, 48 mass% and 59 mass%, induction using a water-cooled copper container The Ti—Al alloy was deoxidized by the melting method. In each dissolution, the atmosphere in the dissolution chamber was Ar, the pressure during dissolution was 7.0 × 10 ⁴ Pa, the blending amount of calcium fluoride in the CaO—CaF ₂ flux was 80% by mass, and the CaO—CaF ₂ flux The amount of added was 10% of the metal mass. The results are shown in FIG.

According to FIG. 1, even when the induction melting method using a water-cooled copper container is used, when the CaO—CaF ₂ flux is added, the Al content is any of 40 mass%, 48 mass%, and 59 mass%. Even in the case, it can be seen that deoxidation is further promoted as compared with the case where the CaO—CaF ₂ flux is not added.

(Amount of calcium fluoride in CaO-CaF ₂ flux)
Using a Ti—Al alloy with an Al content of 40% by mass, changing the blending amount of calcium fluoride in the CaO—CaF ₂ flux to be added, and then using a 100 kW plasma arc furnace under the same conditions as in the previous examples. The Ti—Al alloy was deoxidized by the plasma arc melting used. The CaO—CaF ₂ flux was spread around the Ti—Al alloy before melting. The results are shown in FIG.

The 5400ppm oxygen content after dissolution without the addition of CaO-CaF ₂ flux as a reference, was examined the degree of deoxidation reaction acceleration effect by CaO-CaF ₂ flux added. According to FIG. 2, it can be seen that when CaO—CaF ₂ flux containing 60 to 90% by mass of calcium fluoride in calcium oxide is added, the most remarkable deoxidation reaction promoting effect is obtained. Even when blended in an amount of at least%, there is a significant deoxidation reaction promoting effect. From this test result, it can be seen that a deoxidation effect can be obtained by adding CaO—CaF ₂ flux containing 35 to 95% by mass of calcium fluoride to calcium oxide. According to FIG. 2, it can be seen that deoxidation is not promoted when CaO—CaF ₂ flux containing 30% by mass of calcium fluoride in calcium oxide is added. This is because the melting point of the CaO—CaF ₂ flux is too high and is not melted.

(Changes in mass and Al content of Ti-Al alloy before and after melting)
The material yield due to volatilization when the Ti—Al alloy was melted using a 100 kW plasma arc furnace was evaluated by examining the changes in the mass and Al content of each sample before and after melting. At this time, only Ar was used as the plasma gas, and the pressure during melting was 1.20 × 10 ⁵ Pa.

First, the relationship between the dissolution time and the mass change rate of the sample before and after dissolution is shown in FIG. According to FIG. 3, it can be seen that there is almost no change in the mass of the sample before and after dissolution. Next, FIG. 4 shows the relationship between the Al concentration (content) of the sample and the mass change rate of the sample before and after dissolution. According to FIG. 4, there is almost no change in the mass of the sample before and after melting, and it can be seen that Al is not volatilized by melting using a 100 kW plasma arc furnace. From these results, it can be seen that in the melting using the plasma arc furnace, which is an example of the melting using the water-cooled copper container, the alloy elements Al and further Ti are not volatilized when the Ti—Al alloy is melted.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application includes Japanese patent applications filed on September 4, 2014 (Japanese Patent Application No. 2014-180431), Japanese patent applications filed on September 4, 2014 (Japanese Patent Application No. 2014-180432), and applications filed on January 16, 2015. Based on Japanese Patent Application (Japanese Patent Application No. 2015-6676), Japanese Patent Application filed on January 16, 2015 (Japanese Patent Application No. 2015-6765), Japanese Patent Application filed on June 30, 2015 (Japanese Patent Application No. 2015-131029) The contents of which are incorporated herein by reference.

According to the present invention, a Ti—Al based alloy having a low oxygen content can be manufactured at low cost, which is useful as a method for manufacturing a metal material for an aircraft or an automobile.

Claims (3)

1. A Ti—Al-based alloy containing 40 mass% or more of Al produced by using an alloy material made of titanium material and aluminum material containing 0.1 mass% or more of oxygen in total in an atmosphere of 1.33 Pa or more By dissolving and holding by a dissolution method using a water-cooled copper container,
   A method for deoxidizing a Ti-Al alloy, wherein the oxygen content of the Ti-Al alloy is reduced.
2. _2. The Ti—Al-based alloy deoxidation method according to claim 1, wherein a CaO—CaF ₂ flux containing 35 to 95 mass% of calcium fluoride in calcium oxide is added before or during melting of the Ti—Al alloy. .
3. The Ti-Al alloy deoxidation method according to claim 1 or 2, wherein the melting method using the water-cooled copper container is any one of an arc melting method, a plasma arc melting method, and an induction melting method.

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