Method and device for preparing titanium alloy composite metal based on self-propagating technology

Abstract

According to the method and device for preparing the titanium alloy composite metal based on the self-propagating technology, the hardened layer is prepared on the surface of the titanium alloy through powder metallurgy, the abrasion resistance of the hardened layer can be improved by flexibly adding the hard particles in the metallurgical process, establishment of the hardened layer is not completed at a time, and the hardness of the hardened layer is improved. Through layer-by-layer component design, better chemical interface reaction between layers can be promoted, in the laying process, Ti of the bottommost layer is more than Al, fusion of a bottom layer interface (Ti powder and a titanium alloy matrix) can be promoted, Ti of the top layer is reduced, Al becomes more, interface reactants tend to TiAl, and covering can form Ti-Ti3Al-Ti2Al-TiAl ladder reactants; conditions are created for subsequent high-temperature curing gradient reaction (self-propagating), and WC powder particles are dispersed and distributed in the conditions.

Description

Technical Field

[0001] The invention discloses a method and a device for preparing titanium alloy composite metal based on self-propagating technology, belonging to the technical field of thermal processing. Background Art

[0002] Titanium alloy has higher specific strength and stiffness, as well as lower density, and is an ideal substitute for steel components. However, titanium alloy materials generally do not have the surface wear resistance of steel materials. Therefore, the surface composite of titanium alloy materials has broad application prospects. At present, there are many methods to improve the surface wear resistance of titanium alloys by composite. For example, nitrogen is input into the surface of titanium alloy through thermal process to ensure chemical reaction, thereby producing a hardened layer. However, this method often cannot obtain a deeper hardened layer, and it is impossible to composite the hardened layer and input hard particles. Summary of the invention

[0003] The present invention is designed to address the above-mentioned existing technical situation and provides a method and device for preparing titanium alloy composite metal based on self-propagating technology. Its purpose is to prepare a hardened layer on the surface of the titanium alloy through powder metallurgy, and to flexibly add hard particles through the metallurgical process to improve the wear resistance of the hardened layer.

[0004] To achieve the above purpose, the technical solution of the present invention is as follows:

[0005] The present invention proposes a method for preparing a titanium alloy composite metal based on a self-propagating technology, which is characterized in that: the method firstly mixes and preheats Ti powder and Al powder, the mass ratio of Ti powder to Al powder is 1:9, the preheating temperature is 300-500°C, and the temperature is raised to 600-800°C after being kept warm for 10-30 minutes, and then mixed with WC powder and kept at 600-800°C after being kept warm for another 10-30 minutes, the mass ratio of the mixed Ti powder and Al powder to the mass of WC powder is 8:2-9:1, and then the temperature is kept warm for 1-2 hours, and then the mixed powder of Ti powder, Al powder and WC powder is evenly laid on the surface of a titanium alloy blank 3, and the titanium alloy blank 3 is previously preheated at 600-800°C and kept warm for 1-2 hours;

[0006] Afterwards, the mixing mass ratio of Ti powder to Al powder was adjusted to 2:8, 3:7, and 4:6 in sequence, and the above operation was repeated to obtain four layers of powder laid on the surface of the titanium alloy blank 3, and the mass ratio of Ti powder, Al powder, and WC powder in each powder layer changed in a step-like manner in sequence;

[0007] Afterwards, the titanium alloy blank 3 is heated to 1400-1600° C. During the heating process, nitrogen is used for protection to ensure that the surface of the titanium alloy blank 3 is evenly covered with hot nitrogen. The heating is stopped after 1-2 hours, and the titanium alloy composite metal is prepared after natural cooling.

[0008] During implementation, the purity of the Ti powder, Al powder and WC powder is 99.99%, the particle size of the Ti powder and Al powder is -350 to -450 mesh, and the particle size of the WC powder is -200 to -300 mesh.

[0009] During implementation, when the mixed powder of Ti powder, Al powder and WC powder is laid on the surface of the titanium alloy billet 3, the titanium alloy billet 3 is rotated to ensure uniform laying, and the rotation speed is 5-10 rad / s.

[0010] In the present invention, the device for realizing the method for preparing titanium alloy composite metal based on self-propagating technology comprises a base 1, a titanium alloy blank 3 is arranged on a bracket 2 and fixedly installed on the base 1, the bracket 2 can drive the titanium alloy blank 3 to rotate axially, a mixing drum 5 is arranged above the titanium alloy blank 3, the mixing drum 5 is surrounded by a mixing drum heating sleeve 6, a secondary screen 4 and a mixed powder channel 15 are arranged at the bottom of the mixing drum 5, and two raw material channels are arranged at the top of the mixing drum 5, one of the raw material channels is connected to the WC powder raw material barrel 10 through a WC powder connecting pipe 7, and the other raw material channel is connected to the Ti powder raw material barrel 13 and the Al powder raw material barrel 11 through a Ti powder connecting pipe 14 and an Al powder connecting pipe 12, respectively, and the Ti powder and the Al powder are mixed in the raw material channel, the top of the WC powder connecting pipe 7, the Ti powder connecting pipe 14, and the Al powder connecting pipe 12 are all provided with a primary screen 8, and the WC powder raw material barrel 10, the Ti powder raw material barrel 13, and the Al powder raw material barrel 11 are all surrounded by a raw material barrel heating sleeve 9.

[0011] In the present invention, the steps of the operation process of the above device are as follows:

[0012] Step 1: Raw material preparation

[0013] Put Ti powder, Al powder and WC powder into WC powder raw material cylinder 10, Ti powder raw material cylinder 13 and Al powder raw material cylinder 11 respectively. The purity of Ti powder, Al powder and WC powder is 99.99%. The particle size of Ti powder and Al powder is -350 to -450 mesh, and the particle size of WC powder is -200 to -300 mesh.

[0014] Step 2: Laying the first layer of powder

[0015] Start the raw material barrel heating sleeve 9 around the WC powder raw material barrel 10, the Ti powder raw material barrel 13 and the Al powder raw material barrel 11 for preheating, the preheating temperature is 300-500°C, after keeping warm for 10-30 minutes, the Ti powder and the Al powder enter the Ti powder connecting pipe 14 and the Al powder connecting pipe 12 respectively through the primary screen 8 and are mixed in the raw material channel connecting the two and enter the mixing barrel 5, the mass ratio of Ti powder to Al powder is 1:9, then start the mixing barrel heating sleeve 6 around the mixing barrel 5, heat to 600-800°C and keep warm for 10-30 minutes, the WC powder enters the mixing barrel 5 through the primary screen 8 and the WC powder connecting pipe 7, the ratio of the mixed mass of Ti powder and Al powder to the mass of WC powder is 8:2-9:1;

[0016] The titanium alloy blank 3 is rotated and preheated by the bracket 2, with a rotation speed of 5-10 rad / s and a preheating temperature of 600-800°C. After being kept warm for 1-2 hours, the mixed powder of Ti powder, Al powder and WC powder in the mixing cylinder 5 is conveyed to the surface of the titanium alloy blank 3 through the secondary screen 4 and the mixed powder channel 15. During the conveying process, the mixed powder channel 15 reciprocates along the rotation axis of the titanium alloy blank 3 to ensure that the mixed powder of Ti powder, Al powder and WC powder is evenly laid on the surface of the titanium alloy blank 3;

[0017] Step 3: Laying the second to fourth layers of powder

[0018] The mixing mass ratio of Ti powder to Al powder is adjusted to 2:8, 3:7, and 4:6 in sequence, and the operation of step 2 is repeated to obtain four layers of powder laid on the surface of the titanium alloy blank 3, and the mass ratio of Ti powder, Al powder, and WC powder in each powder layer changes in a step-like manner in sequence;

[0019] Step 4: Heating and curing

[0020] Keep the titanium alloy billet 3 in the rotation and heating state, start the raw material barrel heating sleeve 9 around the WC powder raw material barrel 10, the Ti powder raw material barrel 13 and the Al powder raw material barrel 11, and the mixing barrel heating sleeve 6 around the mixing barrel 5, the heating temperature is 1400-1600°C, and nitrogen is input into the WC powder raw material barrel 10, the Ti powder raw material barrel 13 and the Al powder raw material barrel 11 at the same time. After the nitrogen is heated, it enters the raw material channel through the WC powder connecting pipe 7, the Ti powder connecting pipe 14 and the Al powder connecting pipe 12 respectively, and then passes through the mixing barrel 5 and the mixed powder channel 15 to be transported to the surface of the titanium alloy billet 3. During this process, the mixed powder channel 15 still keeps reciprocating along the rotation axis of the titanium alloy billet 3 to ensure that the surface of the titanium alloy billet 3 is evenly covered with hot nitrogen. After 1-2 hours, stop heating, and wait for the titanium alloy billet 3 to cool naturally to complete the preparation of the titanium alloy composite metal.

[0021] The characteristics and beneficial effects of the technical solution of the present invention are as follows:

[0022] 1. In the scheme of the present invention, the establishment of the hardened layer is not completed in one go. Through the layer-by-layer composition design, the chemical interface reaction between the layers can be promoted to occur better. During the laying process, the Ti in the bottom layer is more than Al, which can promote the fusion of the bottom interface (Ti powder and titanium alloy matrix). The Ti in the top layer is reduced, and the Al becomes more. The interface reactant tends to TiAl, which is enough to form a step reactant of Ti-Ti3Al-Ti2Al-TiAl, creating conditions for the subsequent high-temperature curing gradient reaction (self-propagation), and the WC powder particles are dispersed therein;

[0023] Second, in the scheme of the present invention, with the help of the last high-temperature nitrogen, the reaction proceeds from the outside to the inside, achieving self-propagation, the top layer reacts first, and forms a shell. During the inward reaction process, the actual reaction temperature far exceeds the actual temperature of the nitrogen, which promotes a more thorough interface reaction and a stronger interface bonding.

[0024] 3. The titanium alloy surface hardened layer obtained by the scheme of the present invention uses external energy to induce local chemical reactions, and uses the high reaction heat released during the reaction process to synthesize materials in a very short time. The metals react with each other and interact with the nitrogen in the sealed reaction container, releasing a large amount of heat, further promoting the rapid consumption of the powder mixture layer by layer, with high density. (The step reaction of Ti-Ti3Al-Ti2Al-TiAl is formed), and the hardness of the titanium alloy surface hardened layer prepared can reach HV0.03 and reach 1200-1500; BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the structure of the device in the technical solution of the present invention DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments:

[0027] See attached Figure 1As shown, the device for implementing the method for preparing titanium alloy composite metal based on self-propagating technology described in the technical solution of the present invention includes a base 1, a titanium alloy billet 3 is arranged on a bracket 2 and fixedly installed on the base 1, the bracket 2 can drive the titanium alloy billet 3 to rotate axially, a mixing drum 5 is arranged above the titanium alloy billet 3, the mixing drum 5 is surrounded by a mixing drum heating sleeve 6, a secondary screen 4 and a mixed powder channel 15 are arranged at the bottom of the mixing drum 5, and two raw material channels are arranged on the top of the mixing drum 5, one of the raw material channels is connected with the WC powder raw material barrel 10 through the WC powder connecting pipe 7, and the other raw material channel is connected with the Ti powder raw material barrel 13 and the Al powder raw material barrel 11 through the Ti powder connecting pipe 14 and the Al powder connecting pipe 12, and the Ti powder and the Al powder are mixed in the raw material channel, the top of the WC powder connecting pipe 7, the Ti powder connecting pipe 14, and the Al powder connecting pipe 12 are all provided with a primary screen 8, and the WC powder raw material barrel 10, the Ti powder raw material barrel 13, and the Al powder raw material barrel 11 are all surrounded by the raw material barrel heating sleeve 9.

[0028] The steps of the operation process of preparing titanium alloy composite metal using the above device are as follows:

[0029] Step 1: Raw material preparation

[0030] Put Ti powder, Al powder and WC powder into WC powder raw material cylinder 10, Ti powder raw material cylinder 13 and Al powder raw material cylinder 11 respectively. The purity of Ti powder, Al powder and WC powder is 99.99%. The particle size of Ti powder and Al powder is -350 to -450 mesh, and the particle size of WC powder is -200 to -300 mesh.

[0031] Step 2: Laying the first layer of powder

[0032] Start the raw material barrel heating sleeve 9 around the WC powder raw material barrel 10, the Ti powder raw material barrel 13 and the Al powder raw material barrel 11 for preheating, the preheating temperature is 300-500°C, after keeping warm for 10-30 minutes, the Ti powder and the Al powder enter the Ti powder connecting pipe 14 and the Al powder connecting pipe 12 respectively through the primary screen 8 and are mixed in the raw material channel connecting the two and enter the mixing barrel 5, the mass ratio of Ti powder to Al powder is 1:9, then start the mixing barrel heating sleeve 6 around the mixing barrel 5, heat to 600-800°C and keep warm for 10-30 minutes, the WC powder enters the mixing barrel 5 through the primary screen 8 and the WC powder connecting pipe 7, the ratio of the mixed mass of Ti powder and Al powder to the mass of WC powder is 8:2-9:1;

[0033] The titanium alloy blank 3 is rotated and preheated by the bracket 2, with a rotation speed of 5-10 rad / s and a preheating temperature of 600-800°C. After being kept warm for 1-2 hours, the mixed powder of Ti powder, Al powder and WC powder in the mixing cylinder 5 is conveyed to the surface of the titanium alloy blank 3 through the secondary screen 4 and the mixed powder channel 15. During the conveying process, the mixed powder channel 15 reciprocates along the rotation axis of the titanium alloy blank 3 to ensure that the mixed powder of Ti powder, Al powder and WC powder is evenly laid on the surface of the titanium alloy blank 3;

[0034] Step 3: Laying the second to fourth layers of powder

[0035] The mixing mass ratio of Ti powder to Al powder is adjusted to 2:8, 3:7, and 4:6 in sequence, and the operation of step 2 is repeated to obtain four layers of powder laid on the surface of the titanium alloy blank 3, and the mass ratio of Ti powder, Al powder, and WC powder in each powder layer changes in a step-like manner in sequence;

[0036] Step 4: Heating and curing

[0037] Keep the titanium alloy billet 3 in the rotation and heating state, start the raw material barrel heating sleeve 9 around the WC powder raw material barrel 10, the Ti powder raw material barrel 13 and the Al powder raw material barrel 11, and the mixing barrel heating sleeve 6 around the mixing barrel 5, the heating temperature is 1400-1600°C, and nitrogen is input into the WC powder raw material barrel 10, the Ti powder raw material barrel 13 and the Al powder raw material barrel 11 at the same time. After the nitrogen is heated, it enters the raw material channel through the WC powder connecting pipe 7, the Ti powder connecting pipe 14 and the Al powder connecting pipe 12 respectively, and then passes through the mixing barrel 5 and the mixed powder channel 15 to be transported to the surface of the titanium alloy billet 3. During this process, the mixed powder channel 15 still keeps reciprocating along the rotation axis of the titanium alloy billet 3 to ensure that the surface of the titanium alloy billet 3 is evenly covered with hot nitrogen. After 1-2 hours, stop heating, and wait for the titanium alloy billet 3 to cool naturally to complete the preparation of the titanium alloy composite metal.

Claims

1. A method for preparing a titanium alloy composite metal based on a self-propagating technology, characterized in that: The method firstly mixes Ti powder and Al powder for preheating, wherein the mass ratio of Ti powder to Al powder is 1:9, the preheating temperature is 300-500°C, and then heats up to 600-800°C after keeping the temperature for 10-30 minutes, and then mixes with WC powder and keeps the temperature at 600-800°C after keeping the temperature for another 10-30 minutes, wherein the mass ratio of the mixed Ti powder and Al powder to the mass of WC powder is 8:2-9:1, and then keeps the temperature for 1-2 hours continuously, and then evenly spreads the mixed powder of Ti powder, Al powder and WC powder on the surface of a titanium alloy billet (3), wherein the titanium alloy billet (3) is previously preheated at 600-800°C and kept for 1-2 hours; Afterwards, the mass ratio of the Ti powder to the Al powder is adjusted to 2:8, 3:7, and 4:6 in sequence, and the above operation is repeated to obtain four layers of powder laid on the surface of the titanium alloy blank (3), wherein the mass ratio of the Ti powder, Al powder, and WC powder in each powder layer changes in a step-like manner in sequence; Afterwards, the titanium alloy blank (3) is heated to 1400-1600° C. During the heating process, nitrogen is used for protection to ensure that the surface of the titanium alloy blank (3) is evenly covered by the hot nitrogen. The heating is stopped after 1-2 hours, and the titanium alloy composite metal is prepared after natural cooling.

2. The method for preparing a titanium alloy composite metal based on self-propagating technology according to claim 1, characterized in that: The purity of the Ti powder, Al powder and WC powder is 99.99%, the particle size of the Ti powder and Al powder is -350 to -450 mesh, and the particle size of the WC powder is -200 to -300 mesh.

3. The method for preparing titanium alloy composite metal based on self-propagating technology according to claim 1, characterized in that: When a mixed powder of Ti powder, Al powder and WC powder is laid on the surface of a titanium alloy billet (3), the titanium alloy billet (3) is rotated to ensure uniform laying, and the rotation speed is 5-10 rad / s.

4. A device for implementing the method for preparing titanium alloy composite metal based on self-propagating technology as claimed in claim 1, characterized in that: The device comprises a base (1), a support (2) on which a titanium alloy blank (3) is arranged and fixedly mounted, the support (2) being capable of driving the titanium alloy blank (3) to rotate axially, a mixing drum (5) being arranged above the titanium alloy blank (3), the mixing drum (5) being surrounded by a mixing drum heating sleeve (6), a secondary screen (4) and a mixed powder channel (15) being arranged at the bottom of the mixing drum (5), and two raw material channels being arranged at the top of the mixing drum (5), one of the raw material channels being connected to a WC powder raw material channel through a WC powder connecting pipe (7). The WC powder connecting tube (7), the Ti powder connecting tube (14), and the Al powder connecting tube (12) are connected to the Ti powder raw material tube (13) and the Al powder raw material tube (11), respectively, and the Ti powder and the Al powder are mixed in the raw material channel. The tops of the WC powder connecting tube (7), the Ti powder connecting tube (14), and the Al powder connecting tube (12) are all provided with a primary screen (8). The WC powder raw material tube (10), the Ti powder raw material tube (13), and the Al powder raw material tube (11) are all surrounded by a raw material tube heating sleeve (9).

5. The device for realizing the method for preparing titanium alloy composite metal based on self-propagating technology according to claim 4, characterized in that: The steps of the device's operation process are as follows: Step 1: Raw material preparation Put Ti powder, Al powder and WC powder into WC powder raw material cylinder (10), Ti powder raw material cylinder (13) and Al powder raw material cylinder (11) respectively, the purity of Ti powder, Al powder and WC powder is 99.99%, the particle size of Ti powder and Al powder is -350 to -450 mesh, and the particle size of WC powder is -200 to -300 mesh; Step 2: Laying the first layer of powder The raw material barrel heating sleeve (9) around the WC powder raw material barrel (10), the Ti powder raw material barrel (13) and the Al powder raw material barrel (11) is started to preheat, the preheating temperature is 300-500°C, and after keeping the temperature for 10-30 minutes, the Ti powder and the Al powder pass through the primary screen (8) and enter the Ti powder connecting pipe (14) and the Al powder connecting pipe (12) respectively, and are mixed in the raw material channel connecting the two and enter the mixing barrel (5), the mass ratio of Ti powder to Al powder is 1:9, then the mixing barrel heating sleeve (6) around the mixing barrel (5) is started, heated to 600-800°C and kept the temperature for 10-30 minutes, and the WC powder passes through the primary screen (8) and the WC powder connecting pipe (7) and enters the mixing barrel (5), and the ratio of the mixed mass of Ti powder and Al powder to the mass of WC powder is 8:2-9:1; The titanium alloy blank (3) is rotated and preheated by a support (2) at a rotation speed of 5-10 rad / s and a preheating temperature of 600-800°C. After being kept warm for 1-2 hours, the mixed powder of Ti powder, Al powder and WC powder in the mixing cylinder (5) is transported to the surface of the titanium alloy blank (3) through a secondary screen (4) and a mixed powder channel (15). During the transporting process, the mixed powder channel (15) moves back and forth along the rotation axis of the titanium alloy blank (3) to ensure that the mixed powder of Ti powder, Al powder and WC powder is evenly laid on the surface of the titanium alloy blank (3); Step 3: Laying the second to fourth layers of powder The mass ratio of Ti powder to Al powder is adjusted to 2:8, 3:7, and 4:6, and the operation of step 2 is repeated to obtain four layers of powder laid on the surface of the titanium alloy blank (3), wherein the mass ratio of Ti powder, Al powder, and WC powder in each powder layer changes in a step-like manner; Step 4: Heating and curing The titanium alloy billet (3) is kept in a rotating and heated state, and the raw material barrel heating sleeves (9) around the WC powder raw material barrel (10), the Ti powder raw material barrel (13) and the Al powder raw material barrel (11) and the mixing barrel heating sleeve (6) around the mixing barrel (5) are started, and the heating temperature is 1400-1600° C. At the same time, nitrogen is input into the WC powder raw material barrel (10), the Ti powder raw material barrel (13) and the Al powder raw material barrel (11), and the nitrogen is heated and respectively discharged through the WC powder connecting pipe (7), the T The i powder connecting tube (14) and the Al powder connecting tube (12) enter the raw material channel, and then pass through the mixing barrel (5) and the mixed powder channel (15) to be transported to the surface of the titanium alloy billet (3). During this process, the mixed powder channel (15) still keeps reciprocating along the rotation axis of the titanium alloy billet (3) to ensure that the surface of the titanium alloy billet (3) is evenly covered with hot nitrogen. After 1-2 hours, the heating is stopped and the titanium alloy billet (3) is allowed to cool naturally, thus completing the preparation of the titanium alloy composite metal.

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