A method and apparatus for low-temperature extrusion blanking of modified powder superalloys

Abstract

This invention relates to a low-temperature extrusion billet method and apparatus for modifying powdered high-temperature alloys. The method involves uniformly mixing high-temperature alloy powder with titanium powder and aluminum powder, then suspending the mixed powder in a modification chamber (3) by introducing nitrogen gas, while simultaneously heating the mixed powder in the modification chamber (3) in two stages. The first stage heating temperature is 500-700℃, and after holding at this temperature to ensure thorough heating, the second stage heating temperature is 700-900℃, and this temperature is maintained continuously to obtain modified high-temperature alloy powder. The modified high-temperature alloy powder is then transferred to an extrusion cylinder (7) for radial extrusion. When the pressure reaches 2000-3000 MPa, the pressure is maintained for 0.5-2 hours. After cooling, the low-temperature extruded modified high-temperature alloy powder billet is removed, and after sandblasting and polishing, it becomes a modified high-temperature alloy powder rod. This invention's technical solution modifies the high-temperature alloy powder, utilizing the chemical reaction of the modifying medium to reduce the forming temperature of the high-temperature alloy powder and lower costs.

Description

Technical Field

[0001] This invention relates to a low-temperature extrusion blanking method and apparatus for modified powder superalloys, belonging to the field of hot working technology. Background Technology

[0002] Powder metallurgy (PMMA) is a material developed to address the solidification segregation and deformation difficulties caused by high alloying in cast and forged high-temperature alloys. High-alloyed PMMA possesses excellent comprehensive properties, including high temperature resistance, high strength and toughness, and low crack propagation rate, making it the preferred material for manufacturing high-temperature components such as turbine disks for advanced aero-engines, requiring high performance, high reliability, and long service life. However, high-alloyed PMMA generally has high deformation temperature requirements, leading to certain difficulties in mold development, temperature control, process execution, and microstructure control. Summary of the Invention

[0003] This invention addresses the problems existing in the prior art by providing a low-temperature extrusion blanking method and apparatus for modified powder high-temperature alloys. Its purpose is to reduce the forming temperature of high-temperature alloy powder and lower costs by modifying the high-temperature alloy powder and utilizing the chemical reaction of the modifying medium.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] The low-temperature extrusion billet method for modifying powdered high-temperature alloys, as described in this invention, is characterized by the following steps: First, high-temperature alloy powder is uniformly mixed with titanium powder and aluminum powder. Then, nitrogen gas is introduced into a modification chamber 3 to suspend the mixed powder in a suspended state. Simultaneously, the mixed powder in the modification chamber 3 is heated in two stages. The first stage heating temperature is 500-700℃, and after holding at this temperature to ensure thorough heating, a second stage heating temperature of 700-900℃ is performed and maintained at this temperature to obtain modified high-temperature alloy powder. Next, the modified high-temperature alloy powder is transferred to an extrusion cylinder 7 for radial extrusion. When the pressure reaches 2000-3000 MPa, the pressure and temperature are maintained for 0.5-2 hours. After cooling, the low-temperature extruded modified high-temperature alloy powder billet is removed and, after sandblasting and grinding, becomes a modified high-temperature alloy powder rod.

[0006] In practice, the purity of the titanium powder, aluminum powder, and high-temperature alloy powder is 99.99%, the particle size is -350 mesh to -400 mesh, and the atomic mass ratio of the titanium powder to the aluminum powder is 1:1.

[0007] During implementation, when the extrusion cylinder 7 performs radial extrusion, the moving speed of the pressure wall 5 on its side is 0.001-1s. -1 .

[0008] The apparatus for the low-temperature extrusion blanking method for modifying powder superalloys described above includes a modification box 3. The top of the modification box 3 is connected to the powder conveying pipe 1 through a primary sieve 2. The bottom of the modification box 3 is connected to the upper opening of the extrusion cylinder 7 through a tertiary sieve 10. The extrusion cylinder 7 is mounted on a base 8. The bottom edge of the modification box 3 is connected to the ventilation pipe 4 through a secondary sieve 9. The bottom of the extrusion cylinder 7 is mounted on the base 8. The side of the extrusion cylinder 7 is a pressure wall 5 that can move centripetally. A heater 6 is provided on the inner side of the pressure wall 5.

[0009] The steps for modifying high-temperature alloy powder and performing low-temperature extrusion blanking using the aforementioned apparatus are as follows:

[0010] Step 1: Powder Preparation

[0011] Weigh titanium powder and aluminum powder in an atomic mass ratio of 1:1. The purity of the titanium powder and aluminum powder is 99.99%, and the particle size is -350 mesh to -400 mesh. Mix the titanium powder, aluminum powder and high-temperature alloy powder evenly. The purity of the high-temperature alloy powder to be modified is 99.99%, and the particle size is -350 mesh to -400 mesh.

[0012] Step 2: Modification of High-Temperature Alloy Powder

[0013] High-temperature alloy powder is fed into the modification box 3 through the powder conveying pipe 1 and the primary sieve 2. The ventilation pipe 4 is turned on and nitrogen gas is fed into the modification box 3 through the secondary sieve 9. At this time, the high-temperature alloy powder is in a suspended state in the modification box 3. At the same time, the heater 6 is started to heat the metal powder in the modification box (3) in the first stage. The heating temperature of the first stage is 500-700℃. After the mixed powder is heated through, the titanium powder and aluminum powder mixture is fed into the modification box 3 through the powder conveying pipe 1 and the primary sieve 2. The titanium powder and aluminum powder mixture is attached to the surface of the high-temperature alloy powder under the action of nitrogen gas in the modification box (3). The heating temperature is increased to carry out the second stage of heating. The heating temperature is 700-900℃ and the temperature is kept up. At this time, the high-temperature alloy powder and the titanium powder and aluminum powder mixture attached to the surface are more active under the action of heat radiation. The titanium powder and aluminum powder mixture is more tightly bonded to the surface of the high-temperature alloy powder, thus obtaining the modified high-temperature alloy powder.

[0014] Step 3: Low-temperature extrusion blanking

[0015] Close the ventilation pipe 4, and feed the modified high-temperature alloy powder through the three-stage sieve 10 into the extrusion cylinder 7. Start the pressure wall 5 of the extrusion cylinder to move it towards the center at a speed of 0.001-1s. -1 The metal powder inside the extrusion cylinder 7 is extruded. At this time, the heating temperature of the heater 6 is still maintained at 700-900℃. When the pressure is 2000-3000MPa, the pressure wall 5 stops moving and is kept warm and pressured for 0.5-2 hours.

[0016] Step 4: Post-processing

[0017] After the heat preservation and pressure holding are completed, the heater 6 is turned off. After cooling, the pressure wall 5 moves towards the vest and the modified high-temperature alloy powder blank after low-temperature extrusion is taken out. After sandblasting and grinding, the modified high-temperature alloy powder rod is obtained.

[0018] The features and beneficial effects of the technical solution of this invention are as follows:

[0019] I. In the present invention, titanium powder and aluminum powder collide and adhere with high-temperature alloy powder in a suspended state, so that a layer of titanium powder and aluminum powder is formed on the surface of the high-temperature alloy powder. This layer of titanium powder and aluminum powder can undergo a thermal explosion reaction and plastic deformation under a temperature lower than that at which the high-temperature alloy powder deforms, thereby modifying the high-temperature alloy powder.

[0020] 2. During the modification stage of high-temperature alloy powder at 700-900℃, some aluminum powder has melted, with titanium powder particles mixed in. Some semi-solid aluminum powder remains semi-solid due to the coating of titanium powder, tightly wrapped around the surface of high-temperature alloy powder. The overall elongation of the coating exceeds the elongation of the high-temperature alloy powder.

[0021] Third, during the low-temperature extrusion deformation stage of the modified high-temperature alloy powder, due to the presence of the surface cladding of the high-temperature alloy powder, the dislocations of the high-temperature alloy powder itself are locked within the cladding and undergo infinite recrystallization, which causes the final high-temperature alloy rod to have a microstructure close to ultrafine grains. The ultrafine grains exhibit a cluster morphology, and the boundaries of each cluster are composed of the TixAly phase.

[0022] Fourth, during the extrusion process, by controlling the extrusion tangential speed and tangential force, the local temperature rise promotes the thermal explosion reaction of the last unreacted semi-solid titanium powder and aluminum powder. The temperature rise promotes deformation and reduces deformation resistance. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the extrusion blanking device in the technical solution of the present invention. Detailed Implementation

[0024] The technical solution of the present invention will be further described in detail below with reference to the embodiments:

[0025] See appendix Figure 1As shown, the low-temperature extrusion blanking device for modified powder high-temperature alloys used in the technical solution of the present invention includes a modification box 3. The top of the modification box 3 is connected to the powder conveying pipe 1 through a primary sieve 2. The bottom of the modification box 3 is connected to the upper opening of the extrusion cylinder 7 through a tertiary sieve 10. The extrusion cylinder 7 is installed on the base 8. The bottom edge of the modification box 3 is connected to the ventilation pipe 4 through a secondary sieve 9. The bottom of the extrusion cylinder 7 is installed on the base 8. The side of the extrusion cylinder 7 is a pressure wall 5 that can move centripetally. A heater 6 is provided on the inner side of the pressure wall 5.

[0026] In this embodiment, the steps of modifying high-temperature alloy powder and performing low-temperature extrusion blanking using the aforementioned device are as follows:

[0027] Step 1: Powder Preparation

[0028] Weigh titanium powder and aluminum powder in an atomic mass ratio of 1:1. The purity of the titanium powder and aluminum powder is 99.99%, and the particle size is -350 mesh to -400 mesh. Mix the titanium powder, aluminum powder and high-temperature alloy powder evenly. The purity of the high-temperature alloy powder to be modified is 99.99%, and the particle size is -350 mesh to -400 mesh.

[0029] Step 2: Modification of High-Temperature Alloy Powder

[0030] High-temperature alloy powder is fed into the modification box 3 through the powder conveying pipe 1 and the primary sieve 2. The ventilation pipe 4 is turned on and nitrogen gas is fed into the modification box 3 through the secondary sieve 9. At this time, the high-temperature alloy powder is in a suspended state in the modification box 3. At the same time, the heater 6 is started to heat the metal powder in the modification box (3) in the first stage. The heating temperature of the first stage is 500-700℃. After the mixed powder is heated through, the titanium powder and aluminum powder mixture is fed into the modification box 3 through the powder conveying pipe 1 and the primary sieve 2. The titanium powder and aluminum powder mixture is attached to the surface of the high-temperature alloy powder under the action of nitrogen gas in the modification box (3). The heating temperature is increased to carry out the second stage of heating. The heating temperature is 700-900℃ and the temperature is kept up. At this time, the high-temperature alloy powder and the titanium powder and aluminum powder mixture attached to the surface are more active under the action of heat radiation. The titanium powder and aluminum powder mixture is more tightly bonded to the surface of the high-temperature alloy powder, thus obtaining the modified high-temperature alloy powder.

[0031] Step 3: Low-temperature extrusion blanking

[0032] Close the ventilation pipe 4, and feed the modified high-temperature alloy powder through the three-stage sieve 10 into the extrusion cylinder 7. Start the pressure wall 5 of the extrusion cylinder to move it towards the center at a speed of 0.001-1s. -1 The metal powder inside the extrusion cylinder 7 is extruded. At this time, the heating temperature of the heater 6 is still maintained at 700-900℃. When the pressure is 2000-3000MPa, the pressure wall 5 stops moving and is kept warm and pressured for 0.5-2 hours.

[0033] Step 4: Post-processing

[0034] After the heat preservation and pressure holding are completed, the heater 6 is turned off. After cooling, the pressure wall 5 moves towards the vest and the modified high-temperature alloy powder blank after low-temperature extrusion is taken out. After sandblasting and grinding, the modified high-temperature alloy powder rod is obtained.

Claims

1. A method for modifying high-temperature alloy powder using an apparatus and then extruding it at low temperature, characterized in that: The device includes a modification box (3), the top of which is connected to the powder conveying pipe (1) via a primary sieve (2), and the bottom of which is connected to the upper opening of the extrusion cylinder (7) via a tertiary sieve (10). The extrusion cylinder (7) is mounted on a base (8), and the bottom edge of the modification box (3) is connected to the ventilation pipe (4) via a secondary sieve (9). The bottom of the extrusion cylinder (7) is mounted on the base (8), and the side of the extrusion cylinder (7) is a pressure wall (5) that can move centripetally. A heater (6) is provided on the inner side of the pressure wall (5). The steps of the method are as follows: Step 1: Powder Preparation Titanium powder and aluminum powder were weighed in an atomic mass ratio of 1:

1. The purity of the titanium powder and aluminum powder was 99.99%, and the particle size was -350 mesh to -400 mesh. The purity of the high-temperature alloy powder to be modified was 99.99%, and the particle size was -350 mesh to -400 mesh. Step 2: Modification of High-Temperature Alloy Powder High-temperature alloy powder is fed into the modification box (3) through the powder conveying pipe (1), through the primary sieve (2), and through the ventilation pipe (4). Nitrogen gas is fed into the modification box (3) through the secondary sieve (9). At this time, the high-temperature alloy powder is in a suspended state in the modification box (3). At the same time, the heater (6) is started to heat the metal powder in the modification box (3) in the first stage. The heating temperature of the first stage is 500-700℃. After the mixed powder is heated through, the titanium powder and aluminum powder mixture is fed into the modification box (3) through the powder conveying pipe (1), through the primary sieve (2), and through the modification box (3). The titanium powder and aluminum powder mixture is attached to the surface of the high-temperature alloy powder under the action of nitrogen gas in the modification box (3). The heating temperature is increased to carry out the second stage of heating. The heating temperature is 700-900℃ and the temperature is continuously maintained. At this time, the high-temperature alloy powder and the titanium powder and aluminum powder mixture attached to the surface are more active under the action of heat radiation. The titanium powder and aluminum powder mixture is more tightly bonded to the surface of the high-temperature alloy powder, thus obtaining the modified high-temperature alloy powder. Step 3: Low-temperature extrusion blanking Close the ventilation pipe (4), and feed the modified high-temperature alloy powder through the three-stage sieve (10) into the extrusion cylinder (7). Start the pressure wall (5) of the extrusion cylinder to move towards the center and extrude the metal powder in the extrusion cylinder (7). At this time, the heating temperature of the heater (6) is still maintained at 700-900℃. When the pressure is 2000-3000MPa, the pressure wall (5) stops moving and maintains the temperature and pressure for 0.5-2h. Step 4: Post-processing After the heat preservation and pressure preservation are completed, the heater (6) is turned off. After cooling, the pressure wall (5) moves towards the vest and the modified high-temperature alloy powder blank after low-temperature extrusion is taken out. After sandblasting and polishing, the modified high-temperature alloy powder rod is obtained.

2. The method for modifying high-temperature alloy powder and performing low-temperature extrusion blanking using an apparatus according to claim 1, characterized in that: In step two, the heating temperature in the first stage is 600℃.

3. The method for modifying high-temperature alloy powder and performing low-temperature extrusion blanking using an apparatus according to claim 1, characterized in that: In step two, the heating temperature in the second stage is 800℃.

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