Method for regulating and controlling additive manufacturing submicron titanium-based composite material through ultrasonic energy field

Abstract

The invention discloses a method for regulating and controlling an additive manufacturing submicron titanium-based composite material through an ultrasonic energy field, and belongs to the field of additive manufacturing of titanium-based composite materials. According to the method, superfine ceramic powder is adopted as a reinforcement material of the composite material, the superfine ceramic powder and titanium alloy matrix powder are mixed and dried, and the submicron titanium-based composite material is prepared through the laser melting deposition technology; in the preparation process, an ultrasonic tool head is placed on a deposition layer behind a molten pool, an ultrasonic energy field is synchronously applied to the surface of a sample, and composite material grain refinement is achieved through double influences of the ultrasonic energy field on the molten pool and the deposition layer. Ultrasonic waves are transmitted into a molten pool to generate acoustic streaming and cavitation effects, so that the molten pool is stirred, uniform distribution of C atoms is promoted, the temperature gradient of the molten pool is reduced, uniform nucleation of TiC and betaTi is promoted, and epitaxial growth of TiC and betaTi is delayed; ultrasonic waves act on a high-temperature deposition layer to generate plastic deformation, recrystallization is triggered, alpha Ti is refined, and refining of microstructures of a reinforcement body and a base body is promoted.

Description

Technical Field

[0001] The invention belongs to the field of additive manufacturing of titanium-based composite materials, and specifically relates to a method for regulating and controlling the additive manufacturing of submicron-grade titanium-based composite materials using an ultrasonic energy field. Background Art

[0002] Titanium matrix composites (TMCs) have been widely studied and applied because of their higher strength, hardness, wear resistance and other properties than single titanium alloys. Ceramic particles are widely used as reinforcement materials for TMCs due to their high hardness and good thermal stability, which can significantly improve the mechanical properties of titanium and titanium alloys. At present, TMCs have important applications in the aerospace field and are used to manufacture key components such as aerospace vehicles, rocket engines and civilian centrifugal compressors. This material can significantly reduce the weight of equipment, improve the effectiveness of equipment and the tactical performance of weapons. In addition, TMCs are also used in the manufacture of components such as hot end components of gas turbines, high-performance automotive engine components and chassis structural parts.

[0003] Ceramic particles give TMCs high hardness and fire resistance. Therefore, it is difficult to prepare complex TMCs parts using traditional processing techniques such as forging, casting, and machining. The process is complicated and the manufacturing cost is high. Nowadays, additive manufacturing (AM) technology is developing rapidly. With its high-energy heat source, refractory materials can be effectively melted and near-net rapid prototyping can be achieved, providing a feasible solution for the production and manufacturing of complex TMCs parts.

[0004] Scientific research shows that the use of AM technology to prepare TMCs usually uses ceramic powder particles of tens of microns as reinforcement raw materials, which often leads to incomplete melting or dissolution of ceramic particles, forming undissolved ceramic particles in the formed composite material, which usually leads to easy cracking of the material and reduced strength and plasticity. The use of ceramic powder particles with a particle size of less than 10μm can promote their melting or dissolution more fully, and all ceramic particles are converted into in-situ reinforcement phases, achieving uniform and refined TMCs microstructure. However, there are still problems such as coarse grains of titanium alloy matrix and low plasticity of composite materials.

[0005] Ultrasonic energy field treatment has been proven to be an effective method for regulating the microstructure and properties of metal-based materials. Through the interaction between ultrasound and solid metal or liquid molten pool, grain refinement can be effectively achieved, residual tensile stress can be eliminated, and material properties can be improved. Summary of the invention

[0006] The purpose of the present invention is to provide a method for regulating the use of ultrasonic energy fields in additive manufacturing of submicron titanium-based composite materials. The method uses ultrafine ceramic powder as a reinforcement, uses laser melting deposition technology to prepare submicron titanium-based composite materials, and simultaneously applies ultrasonic energy field treatment during the preparation process. The ultrasonic energy field has a dual effect on the molten pool and the deposited layer, thereby achieving grain refinement of the composite material and improving its comprehensive mechanical properties.

[0007] The invention provides a submicron titanium-based composite material, which comprises a titanium-based alloy and a ceramic reinforcement phase; the composite material phase comprises an α+β type dual-phase titanium alloy and a ceramic reinforcement phase; the α type grain size is 0.5-18 μm, and the β type grain size is 20-200 μm; the ceramic reinforcement phase is dispersed in the titanium-based alloy matrix in the form of short rods and particles, the short rod-shaped ceramic reinforcement phase has a length of 0.5-3.0 μm, a width of 0.17-0.56 μm, and the particle size of the particle-shaped ceramic reinforcement phase is 0.23-0.84 μm.

[0008] Furthermore, the hardness of the composite material is 400-420 HV 0.2 , the tensile strength is 1200~1400MPa, the elongation is 2%~3%, and the breaking strain is 2%~4%.

[0009] The present invention also provides a method for regulating the use of ultrasonic energy fields in additive manufacturing of submicron titanium-based composite materials. Ceramic powder is used as a reinforcement, and laser melting deposition technology is used to prepare the submicron titanium-based composite materials. Ultrasonic energy field treatment is simultaneously applied during the preparation process. The ultrasonic energy field has a dual effect on the molten pool and the deposition layer, thereby achieving grain refinement of the composite material.

[0010] Furthermore, ultrasonic waves are transmitted to the molten pool to generate acoustic flow and cavitation effects, which stir the molten pool, promote the uniform distribution of atoms in the ceramic reinforcement phase and reduce the temperature gradient of the molten pool, thereby promoting the uniform nucleation of the reinforcement phase and βTi and delaying its epitaxial growth; at the same time, ultrasonic waves act on the high-temperature deposited layer to produce plastic deformation, induce recrystallization, and refine αTi; the dual effects of the ultrasonic energy field on the molten pool and the deposited layer promote the refinement of the reinforcement and matrix microstructures, thereby improving the comprehensive mechanical properties of the composite material.

[0011] Furthermore, the control method comprises the following steps:

[0012] Step 1: ball-milling ceramic powder and titanium-based powder, and drying to obtain titanium-based composite material powder;

[0013] Step 2: Add titanium-based composite powder into the powder feeder of the laser melting device, and place the ultrasonic tool on the deposition layer behind the molten pool, and keep the two moving synchronously.

[0014] Furthermore, in step 1, the ceramic powder is TiC and boron carbide; the particle size of the ceramic powder is less than 10 μm, and the volume fraction of the ceramic powder is 1 to 5 vol.%; the material of the titanium-based powder is α+β type dual-phase titanium alloy powder, and the particle size is 45 to 100 μm.

[0015] Furthermore, in step 1, the mass ratio of the grinding balls to the mixed powder is 2.5 to 4:1; the ball milling speed is 180 to 220 r / min -1 , ball milling time is 8 to 12 hours;

[0016] Furthermore, in step 1, the powder is dried at a temperature of 100 to 120° C. and the insulation time is 2 to 3 hours.

[0017] Furthermore, the laser power of the laser melting device is 1200-2400W, and the scanning speed is 300-900mm·min -1 , powder feeding rate is 5~15g·min -1 .

[0018] Furthermore, in step 2, the tool head of the ultrasonic tool is located 20 to 40 mm behind the molten pool, the ultrasonic power is 1000 W, and the ultrasonic frequency is 20 kHz.

[0019] The beneficial effects of the present invention are:

[0020] (1) The present invention provides a method for regulating the effect of ultrasonic energy field on additive manufacturing of submicron-level titanium-based composite materials. The ultrasonic energy field treatment method is used to simultaneously exert an influence on the titanium-based composite material deposition layer in the preparation process: on the one hand, ultrasonic waves are transmitted to the molten pool to generate acoustic flow and cavitation effects, which produce a stirring effect on the molten pool, promote the uniform distribution of C atoms and reduce the temperature gradient of the molten pool, thereby promoting the uniform nucleation of TiC and βTi and delaying their epitaxial growth; on the other hand, ultrasonic waves act on the high-temperature deposition layer to produce plastic deformation, induce recrystallization, and refine αTi; the dual effects of the ultrasonic energy field on the molten pool and the deposition layer promote the refinement of the reinforcement and matrix microstructures, thereby improving the comprehensive mechanical properties of the composite material.

[0021] (2) The present invention provides a method for regulating the use of ultrasonic energy fields in additive manufacturing of submicron titanium-based composite materials, using ultrafine ceramic powder as a reinforcement, which can effectively eliminate undissolved ceramic particles and their adverse effects on mechanical properties, and promote microstructure homogenization;

[0022] (3) The present invention provides a method for regulating the additive manufacturing of submicron titanium-based composite materials using an ultrasonic energy field, wherein the ultrasonic energy field treatment method has the characteristics of simple equipment, simple operation, high efficiency, low energy consumption, and no pollution, and is a low-cost, high-efficiency method for regulating the microstructure and properties of titanium-based composite materials in additive manufacturing;

[0023] (4) The present invention provides a method for regulating the use of ultrasonic energy fields in additive manufacturing of submicron titanium-based composite materials, which can be used for but not limited to the additive manufacturing of submicron titanium-based composite materials, and can be extended to the additive manufacturing of other titanium-based composite materials or metal-based composite materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the process of preparing TiC / Ti6Al4V composite materials by ultrasonic energy field assisted laser melting deposition;

[0025] Figure 2 The TiC, βTi, and αTi grain morphologies of submicron TiC / Ti6Al4V composite materials in the deposited and ultrasonic states;

[0026] Figure 3 Vickers microhardness of submicron TiC / Ti6Al4V composite materials in the deposited state and ultrasonic state;

[0027] Figure 4 Room temperature tensile curves of submicron TiC / Ti6Al4V composite materials in the deposited state and ultrasonic state. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the accompanying drawings.

[0029] The present invention discloses a method for regulating the use of an ultrasonic energy field in additive manufacturing of a submicron titanium-based composite material. The method applies an ultrasonic energy field synchronously during the process of preparing the submicron titanium-based composite material by laser melting deposition. The specific steps are as follows:

[0030] S1. ball-milling ultrafine ceramic powder and titanium alloy spherical powder according to a certain ratio, and then drying to prepare titanium-based composite material powder. The parameters involved include: ultrafine ceramic powder volume fraction, ball milling speed, ball milling time, drying temperature, and insulation time;

[0031] S2, adding the titanium-based composite material powder described in S1 into the powder feeder of the laser melting deposition equipment system to prepare a submicron titanium-based composite material sample, wherein the parameters involved include: laser power, scanning speed, and powder feeding rate;

[0032] S3. In the process of preparing submicron titanium-based composite material samples by laser melting deposition described in S2, the ultrasonic tool head and the laser cladding head are fixed, with the laser cladding head in front and the ultrasonic tool head in the back, and the two are in a relatively static state. During the laser melting deposition process, the two keep synchronous movement, and the ultrasonic tool head is always in contact with the deposition layer at a certain distance behind the molten pool (hereinafter this distance is defined as "ultrasonic spacing"). The ultrasonic energy field propagates to the molten pool and the deposition layer through this position. The parameters involved include: ultrasonic spacing, ultrasonic power, and ultrasonic frequency. At the beginning, the powder feeder is first opened to allow the powder flow to be stably delivered, and then the laser beam is delivered. At the same time, the laser cladding head and the ultrasonic tool head begin to move forward synchronously to start preparing the deposition layer. The ultrasonic generator is turned on in advance to apply the ultrasonic energy field to the ultrasonic tool head, and the ultrasonic tool head is kept lifted and does not contact the deposited layer or the substrate. When the ultrasonic tool head passes the starting point of laser melting deposition, the ultrasonic tool head is dropped and contacts the deposited layer to start applying the ultrasonic energy field. After the laser melting deposition is completed, that is, after the laser and the powder feeder stop working, the ultrasonic tool head continues to move to the end of the deposited layer, the ultrasonic tool head is lifted, and the ultrasonic generator is turned off, thus completing the preparation of a single-pass single-layer deposited layer. After the preparation of the previous deposited layer is completed, the laser cladding head and the ultrasonic tool head are synchronously lifted to the same height as the thickness of the single-layer deposited layer, and returned to the starting end of the deposited layer, and the above preparation process is repeated until the entire sample is formed.

[0033] Preferably, in the titanium-based composite material powder described in S1, the volume fraction of the ultrafine ceramic powder is 1 to 5 vol.%;

[0034] Preferably, the ball milling speed in S1 is 180 to 220 r / min -1 , ball milling time is 8 to 12 hours;

[0035] Preferably, the powder drying temperature in S1 is 100-120° C., and the holding time is 2-3 hours;

[0036] Preferably, the laser power in S2 is 1200-2400W, and the scanning speed is 300-900mm·min -1 , powder feeding rate is 5~15g·min -1 ;

[0037] Preferably, the ultrasonic spacing in S3 is 20-40 mm, the ultrasonic power is 1000 W, and the ultrasonic frequency is 20 kHz.

[0038] Example 1

[0039] A method for regulating the use of ultrasonic energy field in additive manufacturing of submicron-grade titanium-based composite materials, wherein the ultrasonic energy field is simultaneously applied during the process of preparing submicron-grade TiC / Ti6Al4V composite materials by laser melting deposition, and the specific steps are as follows:

[0040] S1. Ultrafine TiC powder (<10 μm) and titanium alloy spherical powder (45-100 μm) were ball-milled at a ratio of 1:99 (volume ratio) at a ball milling speed of 200 r / min. -1 , the ball milling time is 12h; the mixed powder is kept at 110℃ for 2h to prepare 1vol.% TiC / Ti6Al4V composite material powder.

[0041] S2. Add the 1 vol.% TiC / Ti6Al4V composite material powder described in S1 into the powder feeder of the laser melting deposition equipment system. The laser power of the laser melting deposition equipment system is 2100 W and the scanning speed is 600 mm·min -1 , powder feeding rate is 14g·min -1 ; During the process of preparing submicron TiC / Ti6Al4V composite material samples by laser melting deposition, the ultrasonic tool head was placed on the deposition layer 25mm behind the molten pool, and the ultrasonic energy field was synchronously applied to the surface of the deposition layer. The ultrasonic power was 1000W and the ultrasonic frequency was 20kHz, and the submicron TiC / Ti6Al4V composite material samples were prepared;

[0042] S3. During the laser melting deposition process for preparing submicron titanium-based composite material samples as described in S2, the ultrasonic tool head and the laser cladding head are fixed so that the two are in a relatively static state. During the laser melting deposition process, the two maintain synchronous movement. The ultrasonic tool head is always in contact with the deposited layer at a certain distance behind the molten pool (hereinafter this distance is defined as "ultrasonic spacing"). The ultrasonic energy field propagates to the molten pool and the deposited layer through this position. The parameters involved include: ultrasonic spacing, ultrasonic power, and ultrasonic frequency.

[0043] Comparative Example 1

[0044] A method for preparing a submicron titanium-based composite material comprises the following steps:

[0045] S1. Ultrafine TiC powder (<10 μm) and titanium alloy spherical powder (45-100 μm) were ball-milled at a ratio of 1:99 (volume ratio) at a ball milling speed of 200 r / min. -1 , the ball milling time is 12h; the mixed powder is kept at 110℃ for 2h to prepare 1vol.% TiC / Ti6Al4V composite material powder.

[0046] S2. Add the 1 vol.% TiC / Ti6Al4V composite powder described in S1 into the powder feeder of the laser melting deposition equipment system. The laser power is 2100 W and the scanning speed is 600 mm·min. -1 , powder feeding rate is 14g·min -1, and submicron TiC / Ti6Al4V composite material samples were prepared.

[0047] Depend on Figure 1 It can be seen that the substrate is fixed on the workbench, and the laser cladding head is responsible for sending out high-energy laser beams and TiC / Ti6Al4V composite material powders and moving along the scanning direction to form a molten pool on the substrate. After the molten pool solidifies, a deposition layer is formed, which is deposited layer by layer along the deposition direction to form a sample; the ultrasonic tool head is fixed at a certain distance behind the molten pool (this distance is defined as the "ultrasonic spacing") and keeps synchronous movement with the laser cladding head, so that the 20kHz ultrasonic vibration acts on the deposition layer through the ultrasonic tool head, and is also transmitted to the molten pool through the deposition layer, thereby regulating the microstructure and mechanical properties of the composite material after solidification and cooling;

[0048] Depend on Figure 2 It can be seen that in the TiC / Ti6Al4V composite material treated by ultrasonic energy field, the in-situ TiC, βTi, and αTi grains are all refined. After ultrasonic treatment, the size of in-situ TiC is in the range of 0.25-1.5 μm, the size of βTi grain is in the range of 20-200 μm, and the size of αTi grain is in the range of 0.5-18 μm.

[0049] Depend on Figure 3 It can be seen that compared with the comparative example 1 without ultrasonic energy field treatment, the microhardness of the TiC / Ti6Al4V composite material treated with ultrasonic energy field in Example 1 is improved, and the average microhardness is 414.8HV 0.2 ;

[0050] Depend on Figure 4 It can be seen that compared with the comparative example 1 without ultrasonic energy field treatment, the tensile strength and plasticity of the TiC / Ti6Al4V composite material after ultrasonic energy field treatment in Example 1 are improved, the tensile strength is 1340MPa, the elongation is 2.10%, and the fracture strain is increased to 3.14%.

[0051] The method of the present invention utilizes ultrasound to transmit to the molten pool to generate acoustic flow and cavitation effects, produce stirring effects on the molten pool, promote uniform distribution of C atoms and reduce the temperature gradient of the molten pool, thereby promoting uniform nucleation of TiC and βTi and delaying their epitaxial growth; at the same time, ultrasound acts on the high-temperature deposition layer to produce plastic deformation, induce recrystallization, and refine αTi; through the dual effects of the ultrasonic energy field on the molten pool and the deposition layer, the microstructure refinement of the reinforcement and the matrix is ​​promoted, and the comprehensive mechanical properties of the composite material are improved. The method provided by the present invention can be used for, but not limited to, the laser melting deposition technology of titanium-based composite materials, and can be extended to the additive manufacturing technology of other metal-based composite materials.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A submicron titanium-based composite material, characterized in that: The composite material includes a titanium-based alloy and a ceramic reinforcement phase; the composite material phase includes an α+β dual-phase titanium alloy and a ceramic reinforcement phase; the α-type grain size is 0.5 to 18 μm, and the β-type grain size is 20 to 200 μm; the ceramic reinforcement phase is dispersed in the titanium-based alloy matrix in the form of short rods and particles, the short rod-shaped ceramic reinforcement phase has a length of 0.5 to 3.0 μm, a width of 0.17 to 0.56 μm, and the particle size of the granular ceramic reinforcement phase is 0.23 to 0.84 μm.

2. The submicron titanium-based composite material according to claim 1, characterized in that: The hardness of the composite material is 400-420 HV 0.2 , the tensile strength is 1200~1400MPa, the elongation is 2%~3%, and the breaking strain is 2%~4%.

3. A method for regulating the ultrasonic energy field in additive manufacturing of submicron titanium-based composite materials, characterized in that: Ceramic powder is used as reinforcement and laser melting deposition technology is used to prepare submicron titanium-based composite materials. Ultrasonic energy field treatment is simultaneously applied during the preparation process. The ultrasonic energy field has a dual effect on the molten pool and the deposition layer to achieve grain refinement of the composite material.

4. The method for controlling the ultrasonic energy field in additive manufacturing of submicron titanium-based composite materials according to claim 3, characterized in that: Ultrasonic waves are transmitted to the molten pool to generate acoustic flow and cavitation effects, which stir the molten pool, promote the uniform distribution of atoms in the ceramic reinforcement phase and reduce the temperature gradient of the molten pool, thereby promoting the uniform nucleation of the reinforcement phase and βTi and delaying its epitaxial growth; at the same time, ultrasonic waves act on the high-temperature deposited layer to produce plastic deformation, induce recrystallization, and refine αTi; the dual effect of the ultrasonic energy field on the molten pool and the deposited layer promotes the refinement of the reinforcement and matrix microstructures, and improves the comprehensive mechanical properties of the composite material.

5. The method for controlling the ultrasonic energy field in additive manufacturing of submicron titanium-based composite materials according to claim 3, characterized in that: The control method comprises the following steps: Step 1: ball-milling ceramic powder and titanium-based powder, and drying to obtain titanium-based composite material powder; Step 2: Add titanium-based composite powder into the powder feeder of the laser melting device, and place the ultrasonic tool on the deposition layer behind the molten pool, and keep the two moving synchronously.

6. The method for controlling the ultrasonic energy field in additive manufacturing of submicron titanium-based composite materials according to claim 5, characterized in that: In step 1, the ceramic powder is TiC and boron carbide; the particle size of the ceramic powder is less than 10 μm, and the volume fraction of the ceramic powder is 1 to 5 vol.%; the material of the titanium-based powder is α+β type dual-phase titanium alloy powder, and the particle size is 45 to 100 μm.

7. The method for controlling the ultrasonic energy field in additive manufacturing of submicron titanium-based composite materials according to claim 5, characterized in that: In step 1, the mass ratio of the grinding balls to the mixed powder is 2.5 to 4:1; the ball milling speed is 180 to 220 r / min -1 , the ball milling time is 8 to 12 hours.

8. The method for controlling the ultrasonic energy field in additive manufacturing of submicron titanium-based composite materials according to claim 5, characterized in that: In step 1, the powder is dried at a temperature of 100 to 120° C. and the insulation time is 2 to 3 hours.

9. The method for controlling the ultrasonic energy field in additive manufacturing of submicron titanium-based composite materials according to claim 5, characterized in that: In step 2, the laser power of the laser melting device is 1200-2400W, and the scanning speed is 300-900mm·min -1 , powder feeding rate is 5~15g·min -1 .

10. The method for controlling the ultrasonic energy field in additive manufacturing of submicron titanium-based composite materials according to claim 5, characterized in that: In step 2, the tool head of the ultrasonic tool is located 20 to 40 mm behind the molten pool, the ultrasonic power is 1000 W, and the ultrasonic frequency is 20 kHz.

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