TiAl / TC4 alloy laminated composite plate and preparation method thereof

Abstract

The present invention provides a TiAl / TC4 alloy laminated composite plate and a preparation method thereof. The preparation method adopts TiAl 3 、TiH 2 and TC4 low oxygen alloy powder, first TiAl 3 Powder and TiH 2 The powders are uniformly mixed according to the powder ratio to obtain Ti-Al powder; the Ti-Al powder and the TC4 powder are alternately loaded into a package in sequence to form a layered powder blank in which Ti-Al powder layers and TC4 powder layers are alternately stacked on each other; the powder blank is sequentially subjected to hot isostatic pressing treatment, vacuum annealing treatment and multi-pass rolling, which significantly improves the bonding strength of the interfaces of different components of the titanium-aluminum composite plate, reduces the impurity content of the interface, and obtains a TiAl / TC4 alloy laminated composite plate with fine grains and excellent performance.

Description

Technical Field

[0001] The invention relates to the technical field of titanium-aluminum alloy powder metallurgy, and in particular to a TiAl / TC4 alloy laminated composite plate and a preparation method thereof. Background Art

[0002] Titanium aluminum alloy has low density, high specific strength, and can maintain excellent oxidation resistance and creep resistance at high temperatures. Its elastic modulus, creep resistance and other properties are comparable to those of nickel-based high-temperature alloys currently used in large quantities in aerospace engines, while the density of titanium aluminum alloy is only half of that of nickel-based high-temperature alloys or even lower, making it one of the most competitive materials in the temperature range of 650°C to 1000°C. It has received widespread attention in the fields of aviation, aerospace, cruise missile engines, and automobiles involving lightweight and heat-resistant structural parts.

[0003] High-performance layered titanium-aluminum composite materials have always attracted great attention from peers at home and abroad, and have broad application prospects in the fields of bulletproof protection, aerospace, sound insulation and noise reduction, and lightweight automobiles. However, traditional metal layered composite plates are generally prepared by explosion method, and the quality of the material interface is difficult to control, and it is only suitable for preparing thicker titanium alloy composite plates.

[0004] With the increasing demand for reducing plate thickness, improving performance and reducing weight, there is an urgent need to develop composite layered titanium-aluminum plates and their preparation methods that have both mechanical properties and thickness advantages. Summary of the invention

[0005] In view of the shortcomings of the prior art, the main purpose of the present invention is to provide a TiAl / TC4 alloy laminated composite plate and a preparation method thereof, which adopts a powder metallurgy method to prepare a TiAl / TC4 alloy laminated composite plate. 3 、TiH 2 The TC4 low-oxygen alloy powder directly avoids the problem of easy contamination during the processing of single powder and foil. It also avoids the problem of difficult control of the interface bonding quality of different foils when using foil stacking to prepare titanium-aluminum composite plates. It significantly improves the bonding strength of the interfaces of different components of the titanium-aluminum composite plates and reduces the impurity content of the interfaces, thus obtaining TiAl / TC4 alloy composite plates with fine grains, low impurity content and high interface bonding quality.

[0006] In order to achieve the above object, according to a first aspect of the present invention, a method for preparing a TiAl / TC4 alloy laminated composite plate is provided.

[0007] The method for preparing a TiAl / TC4 alloy laminated composite plate by powder metallurgy comprises the following steps:

[0008] TiAl 3 、TiH 2and TC4 powder as raw materials, and the TiAl 3 Powder and the TiH 2 The powders are uniformly mixed according to the powder ratio to obtain Ti-Al powder;

[0009] The Ti-Al powder and the TC4 powder are alternately loaded into the package in sequence, and are respectively filled to a certain thickness to form a layered powder blank in which Ti-Al powder layers and TC4 powder layers are alternately stacked on each other, and the bottom layer and the top layer of the powder blank are both Ti-Al powder layers;

[0010] The powder blank is subjected to hot isostatic pressing treatment, vacuum annealing treatment and multi-pass rolling in sequence to obtain a TiAl / TC4 alloy laminated composite plate.

[0011] Furthermore, the number of layers of the powder blank is 2N+1 layers, wherein N is an integer of 1-50.

[0012] Furthermore, the thickness of each Ti-Al powder layer is 1 to 10 mm, and the thickness of each TC4 powder layer is 1 to 10 mm;

[0013] Preferably, the thickness of each Ti—Al powder layer is 1 to 3 mm, and the thickness of each TC4 powder layer is 1 to 3 mm.

[0014] Furthermore, the Ti-Al powder and the TC4 powder are alternately loaded into the package in sequence by a vibration method and fully vibrated and filled to obtain the powder blank.

[0015] Furthermore, the process conditions of the hot isostatic pressing treatment are: first heating to 500-800°C, pressure 40-60Mpa, maintaining for 1-2h; then heating to 1250-1350°C, pressure 150-250MPa, maintaining for 3-5h, to obtain a TiAl / TC4 alloy billet.

[0016] Furthermore, the process conditions of the vacuum annealing treatment are: temperature of 500-600°C, time of 4-6 hours, pressure of 10 -3 ~10 -5 Pa, and then the TiAl / TC4 alloy billet was obtained after furnace cooling.

[0017] Furthermore, the temperature of the multiple rolling passes is 1200-1300°C, the temperature is kept for 1-2 hours, the rolling rate is 80-120 mm / min, and the final rolling temperature of each pass is controlled to be ≥1200°C, and after each rolling pass, the steel is returned to the furnace for 5-10 minutes to even out the temperature before the next rolling pass is carried out;

[0018] Preferably, the deformation amount of each rolling pass is 15-25%, and the total rolling deformation amount is 60-80%.

[0019] Furthermore, in the Ti-Al powder, the percentage of Al atoms in the total number of all atoms is 40-50%;

[0020] Preferably, the TiAl 3 The average particle size of the powder is 30-40 μm, and the oxygen content is 400-600 ppm;

[0021] Preferably, the TiH 2 The average particle size of the powder is 30-40 μm, and the oxygen content is 600-800 ppm;

[0022] Preferably, the average particle size of the TC4 powder is 30-40 μm, and the oxygen content is 800-1000 ppm.

[0023] In order to achieve the above objective, according to a second aspect of the present invention, a TiAl / TC4 alloy laminated composite plate material is provided.

[0024] The TiAl / TC4 alloy laminated composite plate material is prepared by the above-mentioned preparation method, wherein the organizational structure of the TiAl / TC4 alloy laminated composite plate material comprises Ti-Al alloy layers and TC4 alloy layers stacked in sequence, and both the bottom layer and the top layer are Ti-Al alloy layers; and there is a "serrated" connection interface between the Ti-Al alloy layer and the TC4 alloy layer;

[0025] Wherein, the Ti-Al alloy layer is composed of Ti 3 Al phase and TiAl phase are doped and formed.

[0026] Furthermore, the room temperature tensile strength of the TiAl / TC4 alloy laminated composite plate is ≥1100MPA, the room temperature plasticity is 5-6%, the 700°C tensile strength is 850MPA, and the 700°C plasticity is 10-12%;

[0027] Preferably, the thickness of the TiAl / TC4 alloy laminated composite plate is 1.2-1.4 mm.

[0028] Beneficial effects of the present invention:

[0029] The preparation method provided by the present invention overcomes the problems of large brittleness and easy cracking of existing titanium-aluminum plates, as well as poor interface bonding and high impurity content of titanium-aluminum composite plates prepared from foil.

[0030] The present invention adopts a powder metallurgy method to alternately stack Ti-Al powder and TC4 powder obtained by powder ratio, so that the TC4 powder layer is used as a toughening layer of the TiAl / TC4 alloy composite plate, and the loading energy is absorbed by the TC4 powder layer, thereby improving the fracture toughness of the TiAl / TC4 alloy composite plate.

[0031] The present invention can significantly improve the interface bonding strength between the Ti-Al powder layer and the TC4 powder layer by means of hot isostatic pressing and jacket hot rolling processes, and the interface bonding is good, and the hydrogen element is fully and evenly diffused in the titanium aluminum alloy to refine the grains. After dehydrogenation treatment, multiple hot rolling is performed, and finally a TiAl / TC4 alloy laminated composite plate with fine grains and easy processing can be obtained. DETAILED DESCRIPTION

[0032] The exemplary embodiments of the present disclosure will be described in more detail below. It should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0033] According to a specific embodiment of the present invention, a method for preparing a TiAl / TC4 alloy laminated composite plate by using a powder metallurgy method is provided.

[0034] The preparation method of the TiAl / TC4 alloy laminated composite plate of the present invention comprises the following steps:

[0035] 1) TiAl 3 、TiH 2 and TC4 powder as raw materials, first TiAl 3 Powder and TiH 2 The powders are uniformly mixed according to the powder ratio to obtain Ti-Al powder, wherein the percentage of Al atoms in the Ti-Al powder is 40-50% of the total number of atoms.

[0036] In the present invention, TiAl 3 、TiH 2 Using TC4 low-oxygen alloy powder as raw material powder directly avoids the problem of single powder and foil being easily contaminated during processing.

[0037] In the embodiment of the present invention, TiAl 3 The average particle size of the powder is 30-40 μm, and the oxygen content is 400-600 ppm.

[0038] In an embodiment of the present invention, TiH 2 The average particle size of the powder is 30-40 μm, and the oxygen content is 600-800 ppm.

[0039] In the embodiment of the present invention, the average particle size of TC4 powder is 30-40 μm, and the oxygen content is 800-1000 ppm.

[0040] 2) Ti-Al powder is loaded into the package by vibration method and fully vibrated to a certain thickness to form a Ti-Al powder layer; then TC4 powder is loaded into the package and fully vibrated to a certain thickness to form a TC4 powder layer; the steps are performed alternately to finally obtain a layered powder blank in which Ti-Al powder layers and TC4 powder layers are alternately superimposed on each other, and the bottom layer and the top layer of the powder blank are both Ti-Al powder layers.

[0041] In the present invention, TC4 powder and Ti-Al powder obtained by powder ratio are alternately stacked by a powder metallurgy method, and the TC4 powder layer is used as a toughening layer of the TiAl / TC4 alloy composite plate to absorb the loading energy, thereby improving the fracture toughness of the TiAl / TC4 alloy composite plate.

[0042] In an embodiment of the present invention, the number of layers of the powder blank is 2N+1 layers, wherein N is an integer of 1-50.

[0043] In an embodiment of the present invention, the thickness of the Ti—Al powder layer is 1 to 10 mm.

[0044] As a specific implementation manner, the thickness of the Ti—Al powder layer is 1 to 3 mm.

[0045] In an embodiment of the present invention, the thickness of the TC4 powder layer is 1 to 10 mm.

[0046] As a specific implementation, the thickness of the TC4 powder layer is 1 to 3 mm.

[0047] When the powder blank reaches a predetermined thickness, the package is vacuum-exhausted, and then the exhaust holes are sealed and welded.

[0048] It should be noted that before loading the powder, the package cover is firstly cleaned by ultrasonic cleaning and alcohol scrubbing to remove oil and dust impurities on the surface of the package cover, and then blown dry with hot air.

[0049] 3) The sealed package and powder blank are subjected to hot isostatic pressing treatment.

[0050] The process conditions of hot isostatic pressing are: firstly, the temperature is raised to 500-800℃, the pressure is 40-60Mpa, and maintained for 1-2h to make TiH 2 The powder is heated to decompose hydrogen and diffuse it evenly in the sheath; then the temperature is raised to 1250-1350°C and the pressure is 150-250MPa for 3-5h, so that the hydrogen element participates in the titanium-aluminum reaction as a temporary metal element, which reduces the grain size of the titanium-aluminum alloy to a certain extent, thereby obtaining a dense TiAl / TC4 alloy billet treated with hydrogenation.

[0051] 4) The sheath is removed by machining, and the obtained TiAl / TC4 alloy blank is subjected to vacuum annealing treatment.

[0052] The process conditions of vacuum annealing are: temperature of 500-600℃, time of 4-6h, dehydrogenation reaction to remove hydrogen in the alloy billet, and the pressure of the annealing furnace is 10 -3 ~10 -5 Pa, after furnace cooling, a TiAl / TC4 alloy billet with fine grains and easy processing is obtained.

[0053] 5) The TiAl / TC4 alloy billet is loaded into a new sheath and sealed, and then the sealed sheath is placed in a muffle furnace for multiple rolling passes, and finally the sheath is removed to obtain a TiAl / TC4 alloy laminated composite plate.

[0054] The process of multi-pass rolling is: temperature of 1200-1300℃, insulation for 1-2h, rolling rate of 80-120mm / min, and control the final rolling temperature of each pass to be ≥1200℃. After each rolling pass, return to the furnace for 5-10min to even out the temperature before rolling the next pass.

[0055] The deformation of each pass of multi-pass rolling is 15-25%, and the total deformation of rolling is 60-80%.

[0056] In the present invention, through hot isostatic pressing treatment and jacket hot rolling process, the interfacial bonding strength between the Ti-Al powder layer and the TC4 powder layer can be significantly improved, and the hydrogen element can be fully and evenly diffused in the titanium-aluminum alloy to refine the grains. After dehydrogenation treatment, multiple hot rolling processes are performed, and finally a fine-grained and dense TiAl / TC4 alloy laminated composite plate can be obtained.

[0057] It is worth mentioning that the TiAl / TC4 alloy billet after vacuum annealing can be subjected to wire cutting and chamfering treatment before multiple rolling passes to obtain a billet that meets the processing requirements and has a smooth surface. For example, a slab with a surface smoothness of Ra4 to Ra6, an arc angle of R4 to R6 mm, and a length, width and thickness of (100 to 200) mm*(50 to 120) mm*(4 to 30) mm can be obtained.

[0058] According to a specific embodiment of the present invention, a TiAl / TC4 alloy laminated composite plate material is also provided, and the TiAl / TC4 alloy laminated composite plate material is prepared by the above-mentioned preparation method.

[0059] The organizational structure of the TiAl / TC4 alloy laminated composite plate in the present invention comprises Ti-Al alloy layers and TC4 alloy layers stacked in sequence, and both the bottom layer and the top layer are Ti-Al alloy layers; there is a "serrated" connection interface between the Ti-Al alloy layer and the TC4 alloy layer;

[0060] Wherein, the Ti-Al alloy layer is composed of Ti 3 Al phase and TiAl phase are doped and formed.

[0061] In the present invention, the main components of the composite layer of the laminated composite plate are TC4 phase, Ti 3 Al phase and TiAl phase, among which Ti 3 The Al phase and the TiAl phase are doped to form a Ti-Al alloy layer; the TC4 phase forms a TC4 alloy layer. The laminated structure has obvious characteristics, and the interface is tightly bonded in a "serrated" shape, with good interface bonding, thereby improving the comprehensive mechanical properties of the composite plate.

[0062] The preparation method of the present invention and the prepared TiAl / TC4 alloy laminated composite plate will be described in detail below through specific examples.

[0063] Embodiment 1:

[0064] S1. Powder selection:

[0065] TiAl 3 The average particle size of the powder is 30μm, and the oxygen content is 400-460ppm; TiH 2 The average particle size of the powder is 30 μm, and the oxygen content is 600-660 ppm; the average particle size of the TC4 powder is 30 μm, and the oxygen content is 800-860 ppm;

[0066] S2, Package powder:

[0067] TiAl 3 Powder and TiH 2 The powder is proportioned and evenly mixed according to the Ti-46Al powder, and is loaded into the sleeve by a vibration method, and is fully vibrated and filled, and the thickness of the Ti-46Al powder layer is 1 mm; TC4 powder is then loaded into the sleeve, and is fully vibrated and filled, and the thickness of the TC4 powder layer is 1 mm; Ti-46Al powder layers and TC4 powder layers are alternately superimposed on each other to form a powder blank, and the thickness of the final powder blank is 21 mm, and both the bottom layer and the top layer are Ti-46Al powder layers; when the powder blank reaches a predetermined thickness, the sleeve is vacuum-evacuated, and then the evacuation hole is sealed and welded;

[0068] S3, Hot Isostatic Pressing:

[0069] The package after sealing welding is subjected to hot isostatic pressing treatment. First, the temperature is raised to 500℃ and the pressure is 40Mpa. The temperature is maintained for 2 hours to make TiH 2 The powder is heated to decompose hydrogen and diffuse it evenly in the package. Then the temperature is raised to 1250°C and the pressure is maintained at 150MPa for 5 hours, so that the hydrogen element participates in the titanium-aluminum reaction as a temporary metal element, which reduces the grain size of the titanium-aluminum alloy to a certain extent, thereby obtaining a dense TiAl / TC4 alloy billet treated with hydrogenation.

[0070] S4, vacuum annealing:

[0071] The sheath is removed by machining, and the blank is subjected to vacuum annealing at 500°C for 6 hours to perform a dehydrogenation reaction to remove hydrogen from the alloy blank. During this process, the pressure of the annealing furnace should be maintained at 10 -5 Pa, after furnace cooling, finally obtains TiAl / TC4 alloy billet with fine grains and easy processing;

[0072] S5. Cutting process:

[0073] The blank is subjected to wire cutting and chamfering to obtain a plate blank with a surface finish of Ra4, an arc angle of R4mm, and a length, width and thickness of 100mm*60mm*10mm. The blank is then placed in a new package and sealed with welding;

[0074] S6, package hot rolling:

[0075] The sealed and welded sheath is placed in a muffle furnace, heated to 1200°C with the furnace, kept warm for 1 hour, and subjected to multiple rolling passes. The rolling rate is 120 mm / min, the deformation of each pass is 25%, the total rolling deformation is 60%, and the final rolling temperature of each pass is controlled to be ≥1200°C. After each rolling pass, the next rolling pass is carried out after returning to the furnace for 5 minutes. Finally, the sheath is removed to obtain the TiAl / TC4 alloy laminated composite plate.

[0076] Embodiment 2:

[0077] S1. Powder selection:

[0078] TiAl 3 The average particle size of the powder is 35μm, and the oxygen content is 460-520ppm; TiH 2 The average particle size of the powder is 35μm, and the oxygen content is 660-720ppm; the average particle size of the TC4 powder is 35μm, and the oxygen content is 860-920ppm;

[0079] S2, Package powder:

[0080] TiAl 3 Powder and TiH 2The powder is proportioned and evenly mixed according to the Ti-47Al powder, and is loaded into the sleeve by a vibration method, and is fully vibrated and filled, and the thickness of the Ti-47Al powder layer is 2 mm; TC4 powder is then loaded into the sleeve, and is fully vibrated and filled, and the thickness of the TC4 powder layer is 2 mm; Ti-47Al powder layers and TC4 powder layers are alternately stacked on each other to form a powder blank, and the final height of the powder blank is 25 mm, and the bottom layer and the top layer are both Ti-47Al powder layers; after the powder blank reaches a predetermined thickness, the sleeve is vacuum-evacuated, and then the evacuation hole is sealed and welded;

[0081] S3, Hot Isostatic Pressing:

[0082] The package after sealing welding is subjected to hot isostatic pressing treatment. First, the temperature is raised to 600℃ and the pressure is 50Mpa. The temperature is maintained for 1.5 hours to make TiH 2 The powder is heated to decompose hydrogen and diffuse it evenly in the package. Then the temperature is raised to 1300°C and the pressure is maintained at 200 MPa for 4 hours, so that the hydrogen element participates in the titanium-aluminum reaction as a temporary metal element, which reduces the grain size of the titanium-aluminum alloy to a certain extent, thereby obtaining a dense TiAl / TC4 alloy billet treated with hydrogenation.

[0083] S4, vacuum annealing:

[0084] The sheath is removed by machining, and the blank is subjected to vacuum annealing at 550°C for 5 hours to remove hydrogen from the alloy blank by dehydrogenation reaction. During this process, the pressure of the annealing furnace should be maintained at 10 -4 Pa, after furnace cooling, finally obtains TiAl / TC4 alloy billet with fine grains and easy processing;

[0085] S5. Cutting process:

[0086] The blank is wire cut and chamfered to obtain a slab with a surface finish of Ra4-Ra6, an arc angle of R5mm, and a length, width and thickness of 150mm*80mm*15mm. The blank is then placed in a new package and sealed with welding;

[0087] S6, package hot rolling:

[0088] The sealed and welded sheath is placed in a muffle furnace, heated to 1250°C, kept warm for 1.5 hours, and subjected to multiple rolling passes. The rolling rate is 100 mm / min, the deformation of each pass is 20%, the total rolling deformation is 70%, and the final rolling temperature of each pass is controlled to be ≥1200°C. After each rolling pass, the next rolling pass is carried out after returning to the furnace for 7 minutes. Finally, the sheath is removed to obtain the TiAl / TC4 alloy laminated composite plate.

[0089] Embodiment 3:

[0090] S1. Powder selection:

[0091] TiAl 3 The average particle size of the powder is 40μm, and the oxygen content is 520-600ppm; TiH 2 The average particle size of the powder is 40 μm, and the oxygen content is 720-800 ppm; the average particle size of the TC4 powder is 40 μm, and the oxygen content is 920-1000 ppm.

[0092] S2, Package powder:

[0093] TiAl 3 Powder and TiH 2 The powder is proportioned and evenly mixed according to the Ti-48Al powder, and is loaded into the sleeve by a vibration method, and is fully vibrated and filled, and the thickness of the Ti-48Al powder layer is 3 mm; TC4 powder is then loaded into the sleeve, and is fully vibrated and filled, and the thickness of the TC4 powder layer is 3 mm; Ti-48Al powder layers and TC4 powder layers are alternately stacked on each other to form a powder blank, and the thickness of the final powder blank is 29 mm, and both the bottom layer and the top layer are Ti-48Al powder layers; after the powder blank reaches a predetermined thickness, the sleeve is vacuum-evacuated, and then the evacuation hole is sealed and welded;

[0094] S3, Hot Isostatic Pressing:

[0095] The package after sealing welding is subjected to hot isostatic pressing treatment. First, the temperature is raised to 800℃ and the pressure is 60Mpa. The temperature is maintained for 1 hour to make TiH 2 The powder is heated to decompose hydrogen and diffuse it evenly in the package. Then the temperature is raised to 1320°C and the pressure is maintained at 220MPa for 3 hours, so that the hydrogen element participates in the titanium-aluminum reaction as a temporary metal element, which reduces the grain size of the titanium-aluminum alloy to a certain extent, thereby obtaining a dense TiAl / TC4 alloy billet treated with hydrogenation.

[0096] S4, vacuum annealing:

[0097] The sheath is removed by machining, and the blank is subjected to vacuum annealing at 600°C for 4 hours to perform a dehydrogenation reaction to remove hydrogen from the alloy blank. During this process, the pressure of the annealing furnace should be maintained at 10 -3 Pa, after furnace cooling, finally obtains TiAl / TC4 alloy billet with fine grains and easy processing;

[0098] S5. Cutting process:

[0099] The blank is wire cut and chamfered to obtain a slab with a surface finish of Ra4-Ra6, an arc angle of R6mm, and a length, width and thickness of 200mm*120mm*20mm. The blank is then placed in a new package and sealed with welding;

[0100] S6, package hot rolling:

[0101] The sealed and welded sheath is placed in a muffle furnace, heated to 1280°C with the furnace, kept warm for 2 hours, and subjected to multiple rolling passes. The rolling rate is 80 mm / min, the deformation of each pass is 15%, the total rolling deformation is 75%, and the final rolling temperature of each pass is controlled to be ≥1200°C. After each rolling pass, the next rolling pass is carried out after returning to the furnace for 10 minutes. Finally, the sheath is removed to obtain the TiAl / TC4 alloy laminated composite plate.

[0102] Embodiment 4:

[0103] S1. Powder selection:

[0104] TiAl 3 The average particle size of the powder is 38μm, and the oxygen content is 520-600ppm; TiH 2 The average particle size of the powder is 38 μm, and the oxygen content is 720-800 ppm; the average particle size of the TC4 powder is 38 μm, and the oxygen content is 920-1000 ppm.

[0105] S2, Package powder:

[0106] TiAl 3 Powder and TiH 2 The powder is proportioned and evenly mixed according to the Ti-48Al powder, and is loaded into the sleeve by the vibration method, and is fully vibrated and filled, and the thickness of the Ti-48Al powder layer is 7 mm; TC4 powder is then loaded into the sleeve, and is fully vibrated and filled, and the thickness of the TC4 powder layer is 7 mm; the Ti-48Al powder layer and the TC4 powder layer are alternately stacked to form a powder blank, and the thickness of the final powder blank is 49 mm, and the bottom layer and the top layer are both Ti-48Al powder layers; after the powder blank reaches a predetermined thickness, the sleeve is vacuum-evacuated, and then the evacuation hole is sealed and welded;

[0107] S3, Hot Isostatic Pressing:

[0108] The package after sealing welding is subjected to hot isostatic pressing treatment. The temperature is first raised to 800℃ and the pressure is 55Mpa. The pressure is maintained for 1 hour to make TiH 2 The powder is heated to decompose hydrogen and diffuse it evenly in the package. Then the temperature is raised to 1280°C and the pressure is maintained at 160MPa for 5 hours, so that the hydrogen element participates in the titanium-aluminum reaction as a temporary metal element, which reduces the grain size of the titanium-aluminum alloy to a certain extent, thereby obtaining a dense TiAl / TC4 alloy billet treated with hydrogenation.

[0109] S4, vacuum annealing:

[0110] The sheath is removed by machining, and the blank is subjected to vacuum annealing at 600°C for 4 hours to perform a dehydrogenation reaction to remove hydrogen from the alloy blank. During this process, the pressure of the annealing furnace should be maintained at 10 -3 Pa, after furnace cooling, finally obtains TiAl / TC4 alloy billet with fine grains and easy processing;

[0111] S5. Cutting process:

[0112] The blank is wire cut and chamfered to obtain a slab with a surface finish of Ra4-Ra6, an arc angle of R6mm, and a length, width and thickness of 210mm*110mm*18mm. The blank is then placed in a new package and sealed with welding;

[0113] S6, package hot rolling:

[0114] The sealed and welded sheath is placed in a muffle furnace, heated to 1280°C with the furnace, kept warm for 2 hours, and subjected to multiple rolling passes. The rolling rate is 80 mm / min, the deformation of each pass is 15%, the total rolling deformation is 65%, and the final rolling temperature of each pass is controlled to be ≥1200°C. After each rolling pass, the next rolling pass is carried out after returning to the furnace for 10 minutes. Finally, the sheath is removed to obtain the TiAl / TC4 alloy laminated composite plate.

[0115] In the present invention, conventional testing methods are used to test the mechanical properties of the TiAl / TC4 alloy laminated composite plate obtained in the embodiment, wherein the room temperature tensile strength of the TiAl / TC4 alloy laminated composite plate is ≥1100MPA, the room temperature plasticity is 5-6%, the 700℃ tensile strength is 850MPA, and the 700℃ plasticity is 10-12%.

[0116] It should be noted that room temperature is also generally referred to as normal temperature or general temperature, which is generally defined as 25°C.

[0117] The analysis of crack propagation behavior shows that in the traditional titanium aluminum foil stacking preparation method, cracks are generated and extended from the interface joint. After expanding to a certain stage, they deflect when approaching the next layer, but the overall direction of the cracks is straight and approximates a broken line, which makes it relatively easy to develop and extend. In the powder stacking preparation method, cracks are no longer easily generated from the interface joint, and the development direction of the cracks is more tortuous, making it difficult for them to continue to extend.

[0118] Moreover, the thickness of the TiAl / TC4 alloy laminated composite plate can be in the range of 1.2 to 1.4 mm, thereby achieving the purpose of reducing the thickness of the plate.

[0119] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for preparing a TiAl / TC4 alloy laminated composite plate by powder metallurgy, characterized in that: The following steps are involved: Using TiAl3, TiH2 and TC4 powders as raw materials, and uniformly mixing the TiAl3 powder and the TiH2 powder according to a powder ratio to obtain Ti-Al powder; the TC4 powder has an average particle size of 30-40 μm and an oxygen content of 800-1000 ppm; The Ti-Al powder and the TC4 powder are alternately loaded into the package in sequence, and are respectively filled to a certain thickness to form a layered powder blank in which Ti-Al powder layers and TC4 powder layers are alternately stacked on each other, and the bottom layer and the top layer of the powder blank are both Ti-Al powder layers; The powder blank is subjected to hot isostatic pressing, vacuum annealing and multiple rolling in sequence to obtain a TiAl / TC4 alloy laminated composite plate; The process conditions of the hot isostatic pressing treatment are: firstly heating to 500-800°C, pressure 40-60 MPa, and maintaining for 1-2 h; then heating to 1250-1350°C, pressure 150-250 MPa, and maintaining for 3-5 h, to obtain a TiAl / TC4 alloy billet; The process conditions of the vacuum annealing treatment are: temperature of 500-600°C, time of 4-6 hours, pressure of 10 -3 ~10 -5 Pa, and then the TiAl / TC4 alloy billet was obtained after furnace cooling.

2. The preparation method according to claim 1, characterized in that The number of layers of the powder blank is 2N+1, wherein N is an integer of 1-50.

3. The preparation method according to claim 1 or 2, characterized in that: The thickness of each Ti-Al powder layer is 1-10 mm, and the thickness of each TC4 powder layer is 1-10 mm.

4. The preparation method according to claim 3, characterized in that: The thickness of each Ti-Al powder layer is 1-3 mm, and the thickness of each TC4 powder layer is 1-3 mm.

5. The preparation method according to claim 1, characterized in that: The Ti-Al powder and the TC4 powder are alternately loaded into the package in sequence by a vibration method and fully vibrated and filled to obtain the powder blank.

6. The preparation method according to claim 1, characterized in that: The temperature of the multiple rolling passes is 1200-1300°C, the temperature is kept for 1-2 hours, the rolling rate is 80-120 mm / min, and the final rolling temperature of each pass is controlled to be ≥1200°C. After each rolling pass, the steel is returned to the furnace for 5-10 minutes to even out the temperature before the next rolling pass.

7. The preparation method according to claim 6, characterized in that: The deformation amount of each rolling pass is 15-25%, and the total rolling deformation amount is 60-80%.

8. The preparation method according to claim 1, characterized in that: In the Ti-Al powder, the percentage of Al atoms in the total number of all atoms is 40-50%.

9. The preparation method according to claim 1, characterized in that: The TiAl3 powder has an average particle size of 30-40 μm and an oxygen content of 400-600 ppm.

10. The preparation method according to claim 1, characterized in that: The average particle size of the TiH2 powder is 30-40 μm, and the oxygen content is 600-800 ppm.

11. The TiAl / TC4 alloy laminated composite sheet material prepared by the preparation method according to any one of claims 1 to 10, characterized in that: The organizational structure of the TiAl / TC4 alloy laminated composite plate comprises Ti-Al alloy layers and TC4 alloy layers stacked in sequence, and both the bottom layer and the top layer are Ti-Al alloy layers; there is a "serrated" connection interface between the Ti-Al alloy layer and the TC4 alloy layer; Wherein, the Ti—Al alloy layer is formed by doping Ti3Al phase and TiAl phase.

12. The TiAl / TC4 alloy laminated composite sheet according to claim 11, characterized in that: The room temperature tensile strength of the TiAl / TC4 alloy laminated composite plate is ≥1100MPA, and the tensile strength at 700°C is 850MPA.

13. The TiAl / TC4 alloy laminated composite sheet according to claim 11, characterized in that: The thickness of the TiAl / TC4 alloy laminated composite plate is 1.2-1.4 mm.