Preparation method for rapidly controlling network size of titanium-based composite material

Abstract

The invention belongs to the technical field of titanium-based composite material preparation, and provides a preparation method for rapidly controlling the network size of a titanium-based composite material, which comprises the following steps: respectively carrying out ball milling and powder mixing on titanium alloy spherical powder with a certain particle size range and flocculent TiB2 powder to obtain mixed powder with the TiB2 powder uniformly covering the surface of the titanium alloy powder; and the mixed powder is placed in a mold, the mold is placed in a vacuum hot-pressing sintering furnace to be sintered, furnace cooling is carried out after heat preservation and pressure maintaining, and finally the titanium-based composite materials with the unequal network sizes are obtained. The obtained titanium-based composite material shows different properties in a tensile test and a hardness test, which shows that the effect of regulating the microstructure and further regulating and controlling the mechanical properties can be achieved based on the purpose of changing the network size.

Description

Technical Field

[0001] The invention relates to a preparation method for rapidly controlling the network size of a titanium-based composite material, and belongs to the technical field of titanium-based composite material preparation. Background Art

[0002] Titanium alloys are widely used in aerospace, biomedicine, chemistry and other fields due to their excellent specific strength, corrosion resistance and good biocompatibility. In order to further improve the specific strength, specific stiffness and high temperature performance of titanium alloys, titanium matrix composites (TMCs) are often prepared by introducing reinforcement phases into titanium alloys. TMCs prepared by ball milling and high temperature sintering have a microscopic network structure. Compared with TMCs with uniform distribution of reinforcement, this material shows more superior performance in terms of strength and plasticity.

[0003] It is well known that the network structure size is closely related to the physical properties of the material, but due to the limitations of traditional preparation methods, it is difficult to adjust the network structure size in TMCs to form TMCs with a suitable network size distribution. At the same time, the performance of titanium-based composites prepared by traditional processes often does not meet the requirements, and this new method that can adjust the microstructure is also needed. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a preparation method for quickly controlling the network size of titanium-based composite materials. The method aims to control the size of titanium alloy spherical powder, utilize in-situ reaction to pin the reinforcement to the titanium alloy grain boundary, and quickly prepare a titanium-based composite material with a target network size.

[0005] To achieve the above purpose, titanium alloy spherical powders with different particle size ranges are used as the matrix, and TiB2 is reacted with the Ti element in the titanium alloy matrix to generate TiBw to form a network structure of varying sizes. The technical scheme is as follows: A preparation method for rapidly controlling the network size of a titanium-based composite material, characterized in that it comprises the following steps: a. separately weighing titanium alloy powder raw materials and TiB2 flocculent powder of different particle sizes; b. ball-milling the titanium alloy powder raw materials and the TiB2 flocculent powder to obtain a mixed powder; c. placing the mixed powder into a vacuum hot-pressing sintering furnace for sintering; d. cooling the sintered body with the furnace, maintaining the pressure to a certain temperature and then releasing the pressure to obtain a titanium-based composite material with different network sizes.

[0006] Preferably, the titanium alloy spherical powder is selected from titanium alloy powder with a particle size of 10-200 μm; and the TiB2 is selected from TiB2 flocculent powder with a purity higher than 98%.

[0007] Preferably, the ball milling parameters are: ball milling speed of 80-150 r / min, ball-to-material ratio of 4-8:1, ball milling time of 6-10 h, and the ball milling process is required to be carried out in a high-purity argon atmosphere.

[0008] Preferably, the hot pressing sintering parameters are: sintering temperature is 1100-1300°C, pressure is 20-30MPa, heat and pressure are maintained for 30-60min, temperature is reduced to 700-800°C and pressure is released, and the furnace is cooled to room temperature.

[0009] The above-mentioned samples were subjected to microstructure observation and performance testing; The beneficial effects of this application are: (1) The present invention rapidly prepares titanium-based composite materials with different network sizes by using titanium alloy spherical powders with different particle sizes, thereby achieving the effect of adjusting the microstructure of the titanium-based composite materials and providing a technical reference for further regulating the organizational properties.

[0010] (2) This technical invention has low preparation cost and simple process. The prepared titanium-based composite material has low impurity content and excellent comprehensive performance.

[0011] (3) The present invention uses hot pressing and sintering to pin the TiB reinforcement phase to the titanium alloy grain boundary in a network distribution, thereby effectively improving the mechanical properties of the titanium-based composite material.

[0012] In summary, the present invention provides an effective means for manufacturing a titanium-based composite material with adjustable network size, high purity and low cost by ball milling powder mixing and hot pressing sintering. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 (a) is the cross-sectional microstructure of the TiBw / TA15 composite material with a network size of about 50 μm in Example 1 of the present invention; Figure 1 (b) is the cross-sectional microstructure of the TiBw / TA15 composite material with a network size of about 100 μm in Example 2 of the present invention; Figure 1 (c) is the cross-sectional microstructure of the TiBw / TA15 composite material with a network size of about 150 μm according to Example 3 of the present invention; DETAILED DESCRIPTION

[0014] The above technical scheme of the present application is described in detail below in conjunction with specific embodiments. Among them, the average particle sizes of the TA15 powders are 50μm, 100μm and 150μm respectively. Other raw materials can be obtained from public commercial channels or prepared according to literature unless otherwise specified. According to the relationship vol.%TiB=1.7*wt.%TiB2, when the volume fraction of TiB in the composite material is 5vol.%, the mass ratio of TiB2 to TA15 powder is calculated. Example

[0015] (1) TA15 powder with an average particle size of 50 μm and TiB2 powder were placed in a ball mill and mixed. The ball milling speed was 100 r / min, the ball-to-material ratio was 5:1, and the ball milling time was 6 h. The ball milling process was carried out in a protective atmosphere of high-purity argon. After ball milling, the TiB2 powder evenly covered the surface of the TA15 powder to obtain a uniform mixed powder.

[0016] (2) The mixed powder is filled into a graphite mold and then sintered in a vacuum hot pressing furnace. The vacuum is drawn to 6×10 -2 MPa, the sintering temperature is 1200℃, the pressure is 25MPa, and the temperature is kept for 45min. The temperature is reduced to 800℃ and the pressure is released. After the furnace is cooled to room temperature, it is taken out to obtain a TiBw / TA15 billet with a network size of about 50μm. Example

[0017] TA15 powder with an average particle size of 100 μm and TiB2 powder are placed in a ball mill and mixed. The ball milling speed is 100 r / min, the ball-to-material ratio is 5:1, and the ball milling time is 6 h. The ball milling process is carried out in a protective atmosphere of high-purity argon. After ball milling, the TiB2 powder evenly covers the surface of the TA15 powder to obtain a uniform mixed powder.

[0018] (2) The mixed powder is filled into a graphite mold and then sintered in a vacuum hot pressing furnace. The vacuum is drawn to 6×10 -2 MPa, the sintering temperature is 1200℃, the pressure is 25MPa, the temperature and pressure are kept for 45min, the temperature is reduced to 800℃ and the pressure is released, the furnace is cooled to room temperature and then taken out to obtain a TiBw / TA15 billet with a network size of about 100μm. Example

[0019] (1) TA15 powder with an average particle size of 150 μm and TiB2 powder were placed in a ball mill and mixed. The ball milling speed was 100 r / min, the ball-to-material ratio was 5:1, and the ball milling time was 6 h. The ball milling process was carried out in a protective atmosphere of high-purity argon. After ball milling, the TiB2 powder evenly covered the surface of the TA15 powder to obtain a uniform mixed powder.

[0020] (2) The mixed powder is filled into a graphite mold and then sintered in a vacuum hot pressing furnace. The vacuum is drawn to 6×10 -2 MPa, the sintering temperature is 1200℃, the pressure is 25MPa, the temperature and pressure are kept for 45min, the temperature is reduced to 800℃ and the pressure is released, the furnace is cooled to room temperature and then taken out to obtain a TiBw / TA15 billet with a network size of about 150μm.

[0021] The TiBw / TA15 composite materials with different network sizes prepared in this embodiment were tested accordingly, and the results are as follows: (1) A VEGA Ⅱ SBH scanning electron microscope produced by Czech TESCAN Company was used to observe the metallographic structure of the titanium-based composite materials prepared in Examples 1, 2 and 3. Figure 1 The photos shown in the figure, where (a), (b), and (c) are microscopic morphology images with network sizes of approximately 50μm, 100μm, and 150μm, respectively. It can be seen that the dark black part in the figure is the TiBw reinforcement phase, the gray-black part is the titanium alloy α phase, and the bright thin strip part is the titanium alloy β phase. In the TiBw / TA15 composite material, the whisker-like TiBw reinforcement is distributed at the boundary of the matrix particles, and combined with the matrix, it presents the microscopic characteristics of network distribution. In particular, the size of the titanium alloy powder is controlled at 50μm, 100μm, and 150μm, respectively, creating a TiBw / TA15 composite material with different network sizes.

[0022] (2) A tensile testing machine Instron-5569 universal electronic testing machine was used to carry out room temperature tensile tests on the three samples at a tensile rate of 0.5 mm / min. The test results were as follows: the maximum tensile stress was 1124.5 MPa, and the elongation was 1.4%; the maximum tensile stress was 1084.7 MPa, and the elongation was 4.2%; and the maximum tensile stress was 1108.1 MPa, and the elongation was 1.9%.

[0023] (3) The macroscopic hardness analysis of the three test samples was carried out at room temperature using an HV-1000 automatic turret micro Vickers hardness tester produced by the Shanghai Institute of Optics and Precision Mechanics, Chinese Academy of Sciences. The test results were as follows: the Vickers hardness of the cross section was 398.0 HV, and the Vickers hardness of the longitudinal section was 391.1 HV; the Vickers hardness of the cross section was 379.6 HV, and the Vickers hardness of the longitudinal section was 376.6 HV; the Vickers hardness of the cross section was 377.45 HV, and the Vickers hardness of the longitudinal section was 401.6 HV.

[0024] The present invention includes but is not limited to the above embodiments. Any equivalent replacement or partial modification made under the concept of the present invention is deemed to be within the protection scope of the present invention.

Claims

1. A method for preparing a titanium-based composite material by rapidly controlling the network size, characterized in that: Titanium-based composite materials are prepared by using titanium alloy powders with different particle sizes as raw materials; The preparation method for rapidly controlling the network size of titanium-based composite materials comprises the following steps: TiB2 flocculent powder and titanium alloy powders with different particle sizes are weighed respectively as preparation raw materials; The TiB2 flocculent powder and the titanium matrix are ball-milled to obtain a mixed powder; Putting the mixed powder into a vacuum hot pressing sintering furnace for sintering; The sintered body is cooled in the furnace, and the pressure is released after being maintained at a certain temperature to obtain a titanium-based composite material with different network sizes.

2. A method for preparing a titanium-based composite material by rapidly controlling the network size according to claim 1, characterized in that: In step a, the titanium alloy particles are selected to have a particle size range of 10-200 μm; TiB2 is selected to have a TiB2 flocculent powder with a purity higher than 98%.

3. The method for preparing a titanium-based composite material by rapidly controlling the network size according to claim 1, characterized in that: The ball milling parameters in step b are: ball milling speed of 80-150 r / min, ball-to-material ratio of 4-8:1, ball milling time of 6-10 h, and the ball milling process is required to be carried out in a high-purity argon atmosphere.

4. The method for preparing a titanium-based composite material by rapidly controlling the network size according to claim 1, characterized in that: The hot pressing sintering parameters in step c are: sintering temperature is 1100-1300° C., pressure is 20-30 MPa, and heat and pressure are maintained for 30-60 minutes.

5. The method for preparing a titanium-based composite material by rapidly controlling the network size according to claim 1, characterized in that: In step d, when the temperature drops to 700-800°C, the pressure is released and the furnace is cooled to room temperature.

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