TiAl alloy for forging, TiAl alloy material, and method for manufacturing TiAl alloy material

Abstract

To provide a TiAl alloy for forging capable of die-forging and excellent in hot forging properties, while capable of achieving a TiAl alloy material having excellent oxidation resistance and high-temperature creep strength.SOLUTION: A TiAl alloy for forging includes 42.0 to 43.6 atom% Al, 0.5 to 2.0 atom% Cu, 3.0 to 7.0 atom% Nb and the balance Ti with inevitable impurities.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a TiAl alloy for forging, a TiAl alloy material, and a method for manufacturing a TiAl alloy material. In particular, the present invention relates to a TiAl alloy material having excellent oxidation resistance and creep strength, a forging TiAl alloy capable of obtaining such a TiAl alloy material and having excellent hot forging properties and being capable of die forging, and a method for manufacturing a TiAl alloy material.

Background Art

[0002] For engines of transportation machines and industrial machines, etc., a supercharger is adopted to obtain high combustion energy. Recently, in order to improve the fuel consumption of engines and the response speed, the use of a TiAl alloy having excellent high-temperature resistance and being lightweight as a member for a supercharger has been put into practical use.

[0003] Among various TiAl alloys, conventional TiAl alloys such as TiAl alloys for casting are composed of a γ phase having a face-centered cubic lattice (FCC) structure and an α phase having a hexagonal close-packed lattice (HCP) structure. The microstructure of such a TiAl alloy is characterized in that in the cooling process after heat treatment, thin plate-like γ phases precipitate in the α phase to form a lamellar phase.

[0004] By the way, since hot forged products are superior in both strength and toughness compared to cast products, the development of TiAl alloys for hot forging has been promoted particularly for the purpose of applying them to members that require these characteristics. A component that stabilizes a β phase having a body-centered cubic lattice (BCC) structure that is easily deformed at high temperatures is added to the TiAl alloy for hot forging. Since the β phase is responsible for most of the deformation, hot forging processing is made possible.

[0005] As examples of TiAl alloys that can be hot forged, Patent Document 1 discloses a forging TiAl alloy in which Nb, V, and B are added to Ti and Al, and the grain size of the borides is specified. Patent Document 2 also discloses a TiAl-based alloy containing Al and Nb, in which the relative amounts of the added components are adjusted, and a TiAl-based alloy in which Nb, V, Cr, and Mo are co-added to Ti and Al. Furthermore, Patent Document 3 discloses a titanium-aluminum alloy material containing Ti, Al, Nb, Mo and / or Mn, and B and / or C and / or Si, with a defined proportion of β / B2-Ti phase. Patent Document 4 also discloses a titanium aluminide alloy composed of titanium, aluminum, and niobium, with a predetermined lamellar structure.

[0006] As shown in Patent Documents 1-4, Nb is an important element for improving the oxidation resistance of TiAl alloys, and Nb is added to many TiAl alloys for hot forging. However, when Nb is added alone to a material with a high Al concentration, assuming the formation of a γ phase including the lamellar phase, it is not possible to sufficiently stabilize the β phase in the practical forging heating temperature range of less than 1300°C. Therefore, in many conventional technologies, either a processing process called "constant temperature forging," which has low manufacturability, is used, or Nb is "co-added" with other β-stabilizing elements to form a sufficient β phase in the forging heating temperature range and ensure good hot forgeability.

[0007] Furthermore, forging TiAl alloys require heat treatment after forging to adjust the material structure. Such heat treatments include, for example, a high-temperature heat treatment to recrystallize the α phase of the forged material and promote α single-phase formation, followed by a lower-temperature heat treatment to precipitate γ plates within the α phase and introduce a lamellar structure. The material structure after the second heat treatment becomes the material structure of the TiAl product.

[0008] Furthermore, while the α phase maintains its α state at high temperatures, it becomes more orderly around room temperature and is sometimes referred to as the "α2 phase." Similarly, the β phase takes on a "B2 structure" around room temperature. However, the descriptions of the α and β phases in this specification do not specifically limit the temperature. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent No. 6687118 [Patent Document 2] Japanese Patent Publication No. 2009-215631 [Patent Document 3] Patent No. 5926886 [Patent Document 4] Patent No. 5512964 [Overview of the project] [Problems that the invention aims to solve]

[0010] However, as mentioned above, when Nb is co-added with other β-stabilizing elements, a large amount of β-phase remains even after heat treatment of the TiAl alloy, leading to a problem where the high-temperature creep strength, one of the mechanical properties, decreases. Furthermore, if a component with few β-stabilizing elements is selected to prevent the β phase from remaining after heat treatment, a problem arises where the β phase is insufficient at high temperatures, resulting in inadequate hot forgeability. Thus, it can be said that there is a trade-off relationship between hot forgeability and high-temperature creep strength.

[0011] Furthermore, for hot forging of TiAl alloys, there are two methods: conventional die forging, in which the die is preheated to room temperature or a few hundred degrees Celsius, and for hot forging, in which the die is heated to the same temperature as the forging material, such as 1200°C, for example. -3One example is isothermal forging, which involves forging over a long period of time under conditions of slow strain rate, such as / sec. Of these hot forging methods, isothermal forging can often be processed even if the β phase is insufficient, but isothermal forging results in an extremely long time per stroke, which reduces productivity.

[0012] In other words, when using conventional die forging rather than isothermal forging to ensure excellent oxidation resistance in TiAl alloys, it is necessary to co-add Nb, which is a β-stabilizing element that contributes to improved oxidation resistance, and another β-stabilizing element. However, even when Nb is co-added with other β-stabilizing elements using the methods described in Patent Documents 1 to 4 above, the β phase remains after heat treatment, resulting in insufficient high-temperature creep strength. On the other hand, reducing the amount of β-stabilizing elements added and decreasing the β-phase after heat treatment results in insufficient β-phase at high temperatures, leading to poor hot forgeability.

[0013] The present invention has been made in view of the above problems, and aims to provide a forging TiAl alloy that has excellent hot forging properties and can be die forged, a TiAl alloy material obtained using the forging TiAl alloy that has excellent oxidation resistance and high-temperature creep strength due to the addition of Nb, and a method for producing the TiAl alloy material. [Means for solving the problem]

[0014] The above objective of the present invention is achieved by the following configuration [1] relating to a TiAl alloy for forging. [1] Al: 42.0 atomic% or more and 43.6 atomic% or less, Cu: 0.5 atomic% to 2.0 atomic%, It contains Nb: 3.0 atomic% to 7.0 atomic%, A TiAl alloy for forging, characterized in that the remainder consists of Ti and unavoidable impurities.

[0015] Furthermore, the above objective of the present invention is achieved by the following configuration [2] relating to the TiAl alloy material. [2] Al: 42.0 atomic% or more and 43.6 atomic% or less, Cu: 0.5 atomic % or more and 2.0 atomic % or less, and Nb: 3.0 atomic % or more and 7.0 atomic % or less, and contains the balance consists of Ti and unavoidable impurities, a TiAl alloy material characterized in that the area ratio of the β phase is 0.5% or more and 15.0% or less.

[0016] Furthermore, the above object of the present invention is achieved by the following configuration [3] related to a method for manufacturing a TiAl alloy material. [3] Al: 42.0 atomic % or more and 43.6 atomic % or less, Cu: 0.5 atomic % or more and 2.0 atomic % or less, and Nb: 3.0 atomic % or more and 7.0 atomic % or less, and contains forging a forging TiAl alloy in which the balance consists of Ti and unavoidable impurities to obtain a forged material, and a step of heat-treating the forged material, and has the step of heat-treating the forged material is a first heat-treatment step of heat-treating at a temperature of 1200 °C or more and 1350 °C or less, after the first heat-treatment step, a second heat-treatment step of heat-treating at a temperature of 850 °C or more and 1000 °C or less, a method for manufacturing a TiAl alloy material characterized by having.

Advantages of the Invention

[0017] According to the present invention, it is possible to provide a forging TiAl alloy excellent in hot forging property and capable of die forging, a TiAl alloy material obtained by forging the forging TiAl alloy and having excellent oxidation resistance and high-temperature creep strength, and a method for manufacturing a TiAl alloy material for obtaining the TiAl alloy material.

Brief Description of the Drawings

[0018] [Figure 1] FIG. 1 is a graph showing the relationship between invention examples and comparative examples when the vertical axis is the Cu concentration and the horizontal axis is the Al concentration. [Figure 2]FIG. 2 is a graph showing the relationship between the inventive examples and the comparative examples when the vertical axis represents the minimum creep rate and the horizontal axis represents the β-phase fraction. [Embodiments for Carrying Out the Invention]

[0019] Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as "the present embodiments") will be described in detail. Note that the present invention is not limited to the embodiments described below, and can be arbitrarily modified and implemented without departing from the gist of the present invention.

[0020] [1. TiAl Alloy for Forging] In conventional TiAl alloys, in order to improve hot forging properties, when promoting the formation of the β-phase at high temperatures, there was a problem that the β-phase remained even after heat treatment and the high-temperature creep strength decreased. Therefore, the present inventors have found that by co-adding Nb and Cu at specified concentrations, it is possible to improve the deformation ability of the α-phase during hot forging, ensure a sufficient β-phase during forging, and reduce the β-phase after heat treatment. As a result, good high-temperature creep strength can be obtained, and as a result, both hot forging properties and high-temperature creep strength can be achieved.

[0021] Hereinafter, the components contained in the TiAl alloy for forging according to the present invention and the reasons for limiting the upper and lower limit values of their concentrations will be described in more detail.

[0022] <Al: 42.0 atomic % or more and 43.6 atomic % or less> Al is an element that promotes the formation of an Al2O3 protective film on the surface of the TiAl alloy. By containing a predetermined amount of Al in the alloy, the base of oxidation resistance is improved, the γ-phase is stabilized, a large amount of γ plates are formed in the α-phase, and a lamellar structure is formed, thereby improving the creep strength of the TiAl alloy. If the Al concentration in the TiAl alloy is less than 42.0 atomic%, the desired creep strength cannot be obtained. Therefore, the Al concentration should be 42.0 atomic% or more, preferably 42.5 atomic% or more. On the other hand, if the Al concentration in the TiAl alloy exceeds 43.6 atomic%, the γ phase becomes overly stabilized and γ grains are formed, so that the desired creep strength cannot be obtained, and the hot forging property also deteriorates. Therefore, the Al concentration should be 43.6 atomic% or less, preferably 43.5 atomic% or less.

[0023] <Cu: 0.5 atomic% or more and 2.0 atomic% or less> Cu is an element having the effect of stabilizing the β phase at high temperatures. Appropriately controlling the Cu content in the TiAl alloy is the most important requirement in this embodiment. Also, Cu is an element that has the effect of improving the deformability of the α phase during hot forging and forming the β phase only at the hot forging temperature. If the Cu concentration in the TiAl alloy is less than 0.5 atomic%, the desired hot forging property cannot be obtained. Therefore, the Cu concentration should be 0.5 atomic% or more, preferably 0.7 atomic% or more. On the other hand, if the Cu concentration in the TiAl alloy exceeds 2.0 atomic%, the β phase remains after heat treatment, and the desired creep strength cannot be obtained. Therefore, the Cu concentration should be 2.0 atomic% or less, preferably 1.2 atomic% or less.

[0024] <Nb: 3.0 atomic% or more and 7.0 atomic% or less> Nb is an element having the effect of improving the oxidation resistance of the TiAl alloy. If the Nb concentration in the TiAl alloy is less than 3.0 atomic%, the oxidation resistance of the obtained alloy material deteriorates. Therefore, the Nb concentration should be 3.0 atomic% or more, preferably 4.5 atomic% or more. On the other hand, if the Nb concentration in the TiAl alloy exceeds 7.0 atomic%, the α phase becomes unstable, the formation of lamellar grains cannot be ensured, and the high-temperature creep strength decreases. Therefore, the Nb concentration should be 7.0 atomic% or less, preferably 6.0 atomic% or less.

[0025] <Remainder> The remainder of the TiAl alloy for forging according to this embodiment, excluding the above-mentioned components, consists of Ti and unavoidable impurities. Examples of unavoidable impurities include C, N, O, H, Cl, Fe, Si, Mg, Ca, Mn, Cr, V, Sn, Bi, Ni, Zr, Na, Be, Zn, and the like.

[0026] [2.TiAl alloy material] The TiAl alloy material according to this embodiment is obtained by forging the above-mentioned [1. TiAl alloy for forging] and subjecting it to a predetermined heat treatment. The composition of the TiAl alloy material is the same as that of the above-mentioned TiAl alloy for forging. The characteristics of the TiAl alloy material according to this embodiment will be described in detail below.

[0027] <β phase fraction (area ratio of β phase): 0.5% or more and 15.0% or less> The TiAl alloy material according to the present invention has a β-phase fraction controlled within a predetermined range. If the β-phase fraction is less than 0.5%, grain boundary cracking occurs due to the coarsening of the α-phase. Therefore, the β-phase fraction should be 0.5% or more, and preferably 1.0% or more. On the other hand, if the β-phase fraction exceeds 15.0%, the desired high-temperature creep strength cannot be secured. Therefore, the β-phase fraction should be 15.0% or less, preferably 10.0% or less, and more preferably 5.0% or less.

[0028] The β-phase fraction can be obtained, for example, by using a scanning electron microscope (SEM) to capture backscattered electron images of the cross-section of the TiAl material and calculating the area ratio of the β-phase region relative to the entire field of view. It is preferable to capture backscattered electron images at multiple arbitrary cross-sections and determine the area ratio of the β-phase at each cross-section, and it is preferable to use the average area ratio obtained by averaging these area ratios as the β-phase fraction.

[0029] [3. Method for manufacturing TiAl alloy material] The method for manufacturing the TiAl alloy material according to this embodiment comprises the steps of forging the TiAl alloy material according to this embodiment, as described in [1. TiAl alloy for forging] above, to obtain a forged material, and heat-treating the forged material at a predetermined temperature. The method for manufacturing the TiAl alloy material according to this embodiment will be described in detail below.

[0030] <Process for forging TiAl alloy for forging> In this embodiment, the forging conditions when forging the TiAl alloy for forging are not particularly limited. The forging process may include, for example, a step of heating the TiAl alloy ingot to a predetermined temperature and a step of applying pressure to the heated ingot. It is preferable to select an appropriate range for heating temperature and applied pressure depending on the desired shape.

[0031] <Process of heat treatment of forged material> In this embodiment, the forged material obtained by the above forging process is subjected to two heat treatments. The first heat treatment step aims to bring the metal structure closer to an α-phase single-phase structure. If the temperature in the first heat treatment step is below 1200°C, it may not be possible to bring the metal structure closer to an α-phase single-phase structure. Therefore, the temperature in the first heat treatment step should be 1200°C or higher, preferably 1250°C or higher. On the other hand, if the temperature in the first heat treatment step exceeds 1350°C, the β phase of the resulting TiAl alloy material increases, and the β phase fraction exceeds 15.0%, resulting in a decrease in creep strength. Therefore, it is preferable to set the temperature in the first heat treatment step to 1350°C or lower, and preferably 1300°C or lower.

[0032] The second heat treatment step (second heat treatment step) following the first heat treatment step aims to form the γ phase and create a [α2+γ] lamellar structure. If the temperature in the second heat treatment step is below 850°C, the formation of the γ phase may be insufficient, or the heat treatment time may be prolonged, resulting in lower industrial productivity. Therefore, the temperature in the second heat treatment step should be 850°C or higher, preferably 875°C or higher. On the other hand, if the temperature in the second heat treatment step exceeds 1000°C, the amount of γ phase formation decreases, and the desired lamellar structure necessary for strength cannot be obtained. Therefore, it is preferable that the temperature in the second heat treatment step be 1000°C or lower, and 975°C or lower. Thus, in this embodiment, a TiAl alloy having the composition specified in [1. TiAl alloy for forging] above is forged, and the first and second heat treatment steps described above are performed on the obtained forged material to obtain a TiAl alloy material having the β phase fraction described in [2. TiAl alloy material] above.

[0033] Furthermore, the TiAl alloy material according to this embodiment is obtainable from a forging TiAl alloy that can be die-forged and has excellent hot forgeability. It has excellent high-temperature resistance, is lightweight, and has excellent creep strength, so it is preferable to use it as a component that requires such material properties. Accordingly, the TiAl alloy material according to this embodiment can be suitably used, for example, as a component for internal combustion engines such as turbines in transport machines and industrial machinery. [Examples]

[0034] The following describes examples and comparative examples of the TiAl alloy for forging according to this embodiment.

[0035] [Evaluation of hot forgeability] (Forging process) First, raw materials having the composition shown in Table 1 below were prepared, and a TiAl alloy ingot weighing approximately 9 kg was produced by the Cold Crucible Induction Melting (CCIM) method. The TiAl alloy ingot was cylindrical with a tapered shape, with a diameter of 110 mm at one end face in the axial direction, a diameter of 85 mm at the other end face, and an axial length of 300 mm. Next, cylindrical test pieces with a diameter of 80 mm and an axial length of 120 mm were prepared from the obtained TiAl alloy ingots. After being held at a temperature of 1250°C or higher for 0.5 hours or more, a disc-shaped forged material was produced by uniaxial compression processing using a press machine in the axial direction of the test piece with a reduction ratio of 70-80%. It is considered that even if the reduction ratio is changed by approximately 10%, the evaluation results of hot forgeability and creep strength are not significantly affected.

[0036] (Evaluation test of hot forgeability) Subsequently, the obtained forged material was cut at approximately the center of its radial direction, dividing it into two crescent-shaped forged materials. For each piece, cracks were observed in a cross-sectional area with a radial length of at least 120 mm, and the number of cracks with a depth of 2 mm or more was counted. The crack density was then calculated by dividing the number of cracks by the sum of the longitudinal lengths (24-26 cm) of the cross-sections of the two forged materials obtained by cutting. As an evaluation criterion for hot forgeability, materials with a crack number density of 0.45 (cracks / cm) or less were deemed to have good hot forgeability and passed the test, while materials with a crack number density exceeding 0.45 (cracks / cm) were deemed to have failed the test.

[0037] [Evaluation of creep strength] (Preparation of test material) From the disc-shaped forged material obtained as described above, six rectangular pieces measuring 14 mm in width, 130 mm in length, and 24 mm in thickness were taken from approximately the center in the radial direction, and one of these pieces was arbitrarily selected as the test material for evaluating creep strength.

[0038] (Heat treatment) The above test material was subjected to two heat treatments under various conditions shown in Table 1 below. The first heat treatment aimed to approximate an α single-phase structure, while the second heat treatment aimed to form a γ phase and create a [α2+γ] lamellar structure. For the first heat treatment, the post-treatment temperature was changed in increments of approximately 30°C, and the material structure was observed for all test specimens. The lowest temperature was selected from the specimens in which α-single-phase formation was progressing. The second heat treatment was carried out at a temperature of 950°C for 1 hour, or at a temperature of 900°C for 3 hours, to obtain the heat-treated material.

[0039] (Creep strength evaluation test) From the obtained heat-treated material, a flanged creep test specimen was prepared with a total length of 80 mm, a parallel section diameter of 6 mm, a length of 30 mm, and M12 threads at both longitudinal ends of the specimen. A creep plate test was performed using a single-type creep testing machine. The test conditions were a temperature of 800°C and a stress of 150 MPa. The minimum creep rate was determined from the test data. The minimum creep rate is an indicator of how much deformation occurs at high temperatures and is a value commonly used as one of the indicators of creep strength. The criteria for evaluating creep strength is a minimum creep rate of 3.0 × 10⁻⁶. -7 (sec -1 Those that were below ) were considered to pass, and the minimum creep speed was 3.0 × 10 -7 (sec -1 Those exceeding the specified threshold were deemed to have failed.

[0040] [Observation of the microstructure of TiAl alloy material] (Preparation of test specimens) After taking creep test specimens from the heat-treated material obtained by the above heat treatment, the surface of the remaining material at the longitudinal end was polished to a mirror finish by mechanical and chemical polishing to prepare test specimens for microstructure observation.

[0041] (Measurement of the area fraction of the β phase) Using a scanning electron microscope (SEM) at a magnification of 400x, backscattered electron images of the above-mentioned specimens were captured. The images were taken near the center of the specimen's thickness, and three images were obtained for each specimen. For each SEM image, the presence of the β-phase was identified based on its characteristic bright contrast (Z-contrast reflecting compositional information), and the β-phase region was color-coded using image processing software. Subsequently, the area ratio of the β-phase relative to the entire field of view was determined using the image analysis software "Image Pro Plus" (Media Cybernetics), and the average area ratio of the β-phase across the three images was calculated.

[0042] The average area ratio and evaluation results of the β phase are shown in Table 1 below.

[0043] [Table 1]

[0044] As shown in Table 1 above, Invention Examples No. 1 to 5 satisfy the requirements specified in the present invention in terms of the composition of the TiAl alloy, and the area ratio of the β phase of the TiAl alloy material also satisfies the requirements specified in the present invention, thus achieving both good hot forgeability and high-temperature creep strength.

[0045] On the other hand, in Comparative Example No. 6, the hot forgeability decreased because the Al concentration exceeded the upper limit of the present invention range. In Comparative Example No. 7, the hot forgeability was poor because the Al concentration exceeded the upper limit of the present invention range, and it also exhibited brittle fracture at high temperatures, resulting in brittle fracture immediately after the creep test and a significant decrease in creep strength. In Comparative Example No. 8, the creep strength decreased because the Al and Nb concentrations were below the lower limit of the present invention range, and the Cu concentration exceeded the upper limit of the present invention range. In Comparative Example No. 9, the creep strength decreased because the Nb concentration was below the lower limit of the present invention range, and the Cu concentration exceeded the upper limit of the present invention range. In Comparative Example No. 10, because the Cu concentration exceeded the upper limit of the present invention range, the β phase remained after the first and second heat treatment steps, and the average area ratio of the β phase exceeded the range defined in the present invention, resulting in a decrease in creep strength.

[0046] Figure 1 is a graph showing the relationship between the inventive examples and comparative examples, with Cu concentration on the vertical axis and Al concentration on the horizontal axis. In Figure 1, white indicates good creep strength, and black indicates poor creep strength. Also, "○" indicates good hot forgeability, and "◇" indicates poor hot forgeability. Specifically, "○" represents examples No. 1 to 5, where both hot forgeability and creep strength were good. "●" represents examples No. 8, 9, and 10, where hot forgeability was good but creep strength was reduced. Also, "◇" represents example No. 6, where creep strength was good but hot forgeability was reduced. "◆" represents example No. 7, where both hot forgeability and creep strength were reduced. Note that the area shown by the dashed line in the figure is the region where the Cu concentration and Al concentration are within the range of the present invention. As shown in Figure 1, it has been demonstrated that when the Cu and Al concentrations in the TiAl alloy are within the ranges specified in the present invention, a TiAl alloy material with excellent hot forgeability and particularly excellent creep strength can be obtained.

[0047] Figure 2 is a graph showing the relationship between the inventive example and the comparative example, with the vertical axis representing the minimum creep rate and the horizontal axis representing the β-phase fraction. In Figure 2, "○", "●", "◇", and "◆" are the same as in Figure 1. Comparative Example No. 7, indicated by "◆", fractured instantaneously immediately after the start of the test, so "↑" is indicated in the figure to show that the creep rate was extremely fast. The range shown by the dashed line in the figure is the region where the β-phase fraction is within the range of the present invention and the minimum creep rate is acceptable. As shown in Figure 2, the TiAl alloy material obtained using the forging TiAl alloy according to the present invention and the manufacturing method according to the present invention tended to yield a better minimum creep rate as the residual β-phase fraction decreased. When the β-phase fraction was 5% or less, an even better minimum creep rate was obtained within the present invention. Furthermore, it was shown that when the β-phase fraction was less than 0.5%, the minimum creep rate increased (deteriorated) or the forgeability decreased.

Claims

1. Al: 42.0 at% or more and 43.6 at% or less, Cu: 0.5 atomic% or more and 2.0 atomic% or less, Nb: Contains 3.0 atomic% to 7.0 atomic% A TiAl alloy for forging, characterized in that the remainder consists of Ti and unavoidable impurities.

2. Al: 42.0 at% or more and 43.6 at% or less, Cu: 0.5 atomic% or more and 2.0 atomic% or less, Nb: Contains 3.0 atomic% to 7.0 atomic% The remainder consists of Ti and unavoidable impurities. A TiAl alloy material characterized by having a β-phase area ratio of 0.5% or more and 15.0% or less.

3. A method for producing the TiAl alloy material described in Claim 2, Al: 42.0 at% or more and 43.6 at% or less, Cu: 0.5 atomic% or more and 2.0 atomic% or less, Nb: Contains 3.0 atomic% to 7.0 atomic% A process of forging a forging TiAl alloy, the remainder of which consists of Ti and unavoidable impurities, to obtain a forged material, The process includes a step of heat-treating the forged material, The process of heat-treating the forged material is as follows: A first heat treatment step involves heat treatment at a temperature of 1200°C to 1350°C, A method for producing a TiAl alloy material, characterized by comprising a second heat treatment step of performing heat treatment at a temperature of 850°C to 1000°C after the first heat treatment step.

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