A method for preparing Ti particle reinforced Mg-based composite material

Abstract

The present invention discloses a method for preparing a Ti particle-reinforced Mg-based composite material, comprising the following steps: 1) Weighing according to the stoichiometric ratios of each atom of Mg x Ti y (x = 2-20, y = 1), and then subjecting them to high-energy ball milling to synthesize a metastable MgTi alloy phase with a face-centered cubic (FCC) structure; 2) Subjecting the powder obtained in step 1) to spark plasma sintering (SPS) to obtain a bulk material; 3) Heat-treating the sintered bulk obtained in step 2) to decompose and precipitate Ti particles from the metastable MgTi phase, obtaining a composite material in which fine Ti particles are dispersed in the Mg matrix; 4) Hot-extruding the composite material obtained in step 3) to obtain a Ti particle-reinforced Mg-based composite material rod. This preparation method has advanced technology. The density of the Ti particle-reinforced Mg-based composite material reaches 99-99.5%, the Ti particles are uniformly distributed in the Mg matrix, the volume fraction of the Ti particles is 3-30 v.%, the average particle size is 1-2 μm, and the strength of the Ti particle-reinforced Mg-based composite material rod is significantly improved.

Description

Technical Field

[0001] The invention relates to a method for preparing a high-strength Ti particle reinforced Mg-based composite material, belonging to the technical field of high-performance metal-based composite material preparation. Background Art

[0002] Adding reinforcing particles to form composites has been shown to be an effective strategy to improve the mechanical properties of magnesium and its alloys. Commonly used reinforcing materials are ceramic particles such as carbides, oxides or borides. In recent years, hard metal particles (Ti, Fe, etc.) have received increasing attention as reinforcing phases in magnesium-based composites due to their inherent ductility and good interfacial compatibility. Due to the same close-packed hexagonal crystal structure, Ti and Mg are more likely to form a coherent interface, thereby obtaining high-performance Mg-based composites.

[0003] At present, the preparation of Ti particle reinforced Mg-based composites mainly adopts stirring casting and powder metallurgy and other derivative technologies based on stirring casting and powder metallurgy. However, since Ti and Mg are immiscible and do not form intermetallic compounds, and the melting point (924 K) and density (1.74 g / cm 3 ) is much lower than the melting point (1941 K) and density (4.51 g / cm 3), which makes it very difficult to prepare uniformly distributed Ti particle-reinforced Mg-based composites. In addition, the surface of the added reinforcement phase particles inevitably contains impurities such as oxides, which affects the interface compatibility between the reinforcement phase and the matrix, and the interface bonding force is weak. Furthermore, the size of the added reinforcement phase particles is generally larger, and the smaller the size of the particles, the more difficult it is to disperse and distribute. For example, Alicja Krella et al. (Alicja Krella, Sravya Tekumalla, Manoj Gupta, Influence of micro Tiparticles on resistance to cavitation erosion of Mg-xTi composites, Mechanics of Materials, 154 (2021), 103705) prepared Mg-xTi (x = 0, 2.5, 5, 10, 15 wt%) composites by separate melt deposition technology. With the increase of Ti content, the agglomeration of Ti particles becomes more and more serious, and the density of the material continues to decrease. G. Garces et al. (G. Garces, J. Medina, P. Perez, A. Stark, N.Schell, P. Adeva, The effect of temperature on load partitioning evolution inmagnesium metal matrix composite reinforced with Ti particles using in-situsynchrotron radiation diffraction experiments, Journal of Magnesium and Alloys, 11 (2023), 706–719) prepared Mg-15 v.%Ti composites using ball milling and hot extrusion technology. The results showed that the Ti particles were severely agglomerated, and their compressive strength and compressive yield strength were only 215.8MPa and 322MPa, respectively. The above factors in the material make it difficult for the mechanical properties of Ti particle reinforced Mg-based composites prepared by stirring casting and powder metallurgy to achieve the expected results.

[0004] Therefore, a method to obtain dispersed Ti particles is very important for preparing Ti particle reinforced Mg-based composites. Summary of the invention

[0005] The present invention aims to provide a method for preparing a high-strength Ti particle reinforced Mg-based composite material, which has the advantages of high repeatability and high mechanical properties of the prepared material.

[0006] The technology proposed in the present invention first utilizes high-energy ball milling to synthesize a Mg-Ti metastable alloy phase, and then controls the decomposition of the metastable phase through heat treatment after consolidation to generate Ti particles with small size and dispersed distribution on the Mg matrix; the preparation method of the present invention can obtain a Ti particle-reinforced Mg-based composite material with smaller particle size, more uniform distribution, and higher interface bonding strength with the matrix.

[0007] The present invention provides a method for preparing a Ti particle reinforced Mg-based composite material, comprising the following steps:

[0008] (1) Press Mg x Ti y The stoichiometric ratios of each atom (x=2-20, y=1) were weighed, and then they were subjected to high-energy ball milling to synthesize the MgTi metastable phase;

[0009] (2) subjecting the powder obtained in step (1) to spark plasma sintering to obtain a bulk material;

[0010] (3) heat treating the sintered block obtained in step (2) to separate Ti particles from the MgTi metastable phase, thereby obtaining a composite material in which fine Ti particles are dispersed in the Mg matrix;

[0011] (4) The composite material obtained in step (3) is hot extruded to obtain a Ti particle reinforced Mg-based composite material rod.

[0012] The chemical raw materials used in the present invention are: magnesium powder, titanium powder, anhydrous ethanol, stearic acid, and argon gas. All the processes of powder preparation, powder filling, and powder extraction in the present invention are all performed in a glove box filled with argon gas.

[0013] The above preparation method specifically comprises the following steps:

[0014] (1) Synthesis of FCC-structured MgTi metastable phase by high-energy ball milling

[0015] The synthesis of MgTi metastable phase was carried out in a ball mill;

[0016] First press Mg x Ti y Each atomic stoichiometric ratio is weighed, and 1-1.5 wt.% of the total mass of Mg and Ti raw materials is added with stearic acid to prevent cold welding during the subsequent ball milling process. The prepared powder is placed in an agate ball mill, and then three agate balls of different sizes are loaded into the ball mill. Furthermore, the diameters of the agate balls are Φ5 mm, Φ8 mm and Φ10 mm, respectively, and the ball mass ratio is 2:5:3;

[0017] The specific process of ball milling is as follows: ① The ball mill jar is sealed and filled with argon gas to protect the powder from contacting the air during the ball milling process; ② The ball mill jar is fixed on the ball mill; ③ The ball mill is turned on, the ball milling speed is 350 rpm, and the ball milling time is 30-40 hours; ④ After the ball milling is completed, the ball mill is turned off, the ball mill jar is taken out, opened in the glove box, the powder is taken out, and sealed for standby use;

[0018] (2) Spark plasma sintering:

[0019] Sintering is carried out in a spark plasma sintering furnace under the protection of argon gas, plasma discharge heating, pressure motor pressure, and external water circulation cooling.

[0020] In a glove box, the ball milled powder is loaded into a sintering mold made of graphite with an inner diameter of Φ40 mm;

[0021] Open the spark plasma sintering furnace, place the graphite mold vertically on the workbench in the furnace chamber, and fix it;

[0022] Close the discharge plasma sintering furnace, turn on the vacuum pump, extract the air in the furnace, and make the pressure in the furnace reach 0.1-1 Pa; open the argon bottle, input argon into the furnace, and make the pressure in the furnace reach 1-1.1 atmospheres; turn on the plasma discharge heater, heat to 560-570 ℃, and keep warm for 10-15 min; stop heating and pressurizing, and cool to room temperature with the furnace under the protection of argon; close the argon bottle, open the furnace and mold, and take out the metal block in the open and close mold;

[0023] (3) Heat treatment

[0024] The surface of the sintered metal block is polished and then tightly wrapped with tin foil to avoid contact with air; then the metal block is placed in a muffle furnace, the power of the muffle furnace is turned on, the temperature is raised to 500-520 ℃, and the temperature is kept for 60-70 hours; the power of the muffle furnace is turned off, the temperature is cooled to room temperature, and the metal block is taken out;

[0025] (4) Hot extrusion

[0026] Place the metal block on a steel plate and use 400-grit sandpaper to polish the periphery and front and back surfaces of the metal block to make it smooth;

[0027] The polished metal block is placed in a steel extrusion die; the extruder is started to perform hot extrusion at an extrusion temperature of 330-360 °C and an extrusion ratio of 16:1. After the extrusion, a rod with a diameter of Φ10 mm is obtained.

[0028] The mass purity of the Mg powder and Ti powder used in the above method is ³99.9%, the particle size of the magnesium powder is 75 µm-150 μm, and the particle size of the titanium powder is <75 μm;

[0029] The Ti particle reinforced Mg-based composite material rod prepared by the present invention is packed with soft materials and stored in a clean environment to prevent moisture, sunlight, acid, alkali and salt corrosion. The storage temperature is 20° C. and the relative humidity is ≤10%.

[0030] Beneficial effects of the present invention:

[0031] The present invention is aimed at the situation that the mechanical properties of metal magnesium are low. Mg powder and Ti powder are first ball-milled to prepare metal powder containing FCC structure MgTi phase, and then plasma discharge sintering is performed to prepare metal blocks, and then heat treatment is performed to decompose the MgTi metastable phase and precipitate uniform and fine Ti particles. Finally, Ti particle-reinforced Mg-based composite material rods are obtained by hot extrusion. This preparation method has advanced technology, accurate and detailed data, good metallographic structure density of the composite material, refined grains, density of 99-99.5%, Ti particles are evenly distributed in the Mg matrix, the volume fraction of Ti particles is 3-30v.%, the average particle size is 1-2μm, and the compressive strength, compressive yield strength and Vickers microhardness of the Ti particle-reinforced Mg-based composite material rods are 400-600MPa, 400-600MPa and 130-210HV respectively. 1.0 , is a method for preparing advanced Ti particle reinforced Mg-based composite rods. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the XRD pattern of the ball-milled powder obtained in step 1) of Example 1;

[0033] Figure 2 The metallographic image of the Ti particle reinforced Mg-based composite rod in step 4) of Example 1;

[0034] Figure 3 TEM image of the Ti particle reinforced Mg-based composite rod in step 4) of Example 1;

[0035] Figure 4 This is a graph showing the size distribution of Ti particles in the composite material prepared in Example 1;

[0036] Figure 5 These are the compressive stress-strain curves of pure magnesium and the Ti particle reinforced Mg-based composite rod prepared in Example 1. DETAILED DESCRIPTION

[0037] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0038] The present invention provides a method for preparing a high-strength Ti particle reinforced Mg-based composite material, comprising the following steps:

[0039] (1) Press Mg x Ti y The stoichiometric ratio of each atom (x=2-20, y=1) is weighed, and then they are subjected to high-energy ball milling to synthesize the MgTi metastable phase; the synthesis of the MgTi metastable phase is carried out in a ball mill;

[0040] First press Mg x Ti y Each atomic stoichiometric ratio is weighed, and stearic acid is added at a content of 1-1.5 wt.% of the total mass of Mg and Ti raw materials to prevent cold welding during the subsequent ball milling process. The prepared powder is placed in an agate ball mill, and then three agate balls of different sizes are loaded into the ball mill. Furthermore, the diameters of the agate balls are Φ5 mm, Φ8 mm and Φ10 mm, respectively, and the ball mass ratio is 2:5:3;

[0041] The specific process of ball milling is as follows: ① The ball mill jar is sealed and filled with argon gas to protect the powder from contacting the air during the ball milling process; ② The ball mill jar is fixed on the ball mill; ③ The ball mill is turned on, the ball milling speed is 350 rpm, and the ball milling time is 30-40 hours; ④ After the ball milling is completed, the ball mill is turned off, the ball mill jar is taken out, opened in the glove box, the powder is taken out, and sealed for standby use;

[0042] (2) subjecting the powder obtained in step (1) to spark plasma sintering to obtain a bulk material; the sintering is carried out in a spark plasma sintering furnace under the protection of argon gas, plasma discharge heating, pressure motor pressure, and external water circulation cooling;

[0043] In a glove box, the ball milled powder is loaded into a sintering mold made of graphite with an inner diameter of Φ40 mm;

[0044] Open the spark plasma sintering furnace, place the graphite mold vertically on the workbench in the furnace chamber, and fix it;

[0045] Close the discharge plasma sintering furnace, turn on the vacuum pump, extract the air in the furnace, and make the pressure in the furnace reach 0.1-1 Pa; open the argon bottle, input argon into the furnace, and make the pressure in the furnace reach 1-1.1 atmospheres; turn on the plasma discharge heater, heat to 560-570 ℃, and keep warm for 10-15 min; stop heating and pressurizing, and cool to room temperature with the furnace under the protection of argon; close the argon bottle, open the furnace and mold, and take out the metal block in the open and close mold;

[0046] (3) heat treating the sintered block obtained in step (2) to separate Ti particles from the MgTi metastable phase, thereby obtaining a composite material in which fine Ti particles are dispersed in the Mg matrix; the specific process is as follows: polishing the surface of the sintered metal block clean, and then wrapping it tightly with tin foil to avoid contact with air; then placing the metal block in a muffle furnace, turning on the power of the muffle furnace, heating it to 500-520°C, and keeping it warm for 60-70 hours; turning off the power of the muffle furnace, cooling it to room temperature, and then taking out the metal block;

[0047] (4) hot extruding the composite material obtained in step (3) to obtain a Ti particle reinforced Mg-based composite material rod;

[0048] The specific process is as follows: place the metal block on a steel plate, and use 400-grit sandpaper to polish the periphery and the front and back surfaces of the metal block to make it smooth;

[0049] The polished metal block is placed in a steel extrusion die; the extruder is started to perform hot extrusion at an extrusion temperature of 330-360 °C and an extrusion ratio of 16:1. After the extrusion, a rod with a diameter of Φ10 mm is obtained.

[0050] The chemical raw materials used in the present invention are: magnesium powder, titanium powder, anhydrous ethanol, stearic acid, and argon gas. All the processes of powder preparation, powder filling, and powder extraction in the present invention are all performed in a glove box filled with argon gas.

[0051] The mass purity of the Mg powder and Ti powder used in the present invention is ³99.9%, the particle size of the magnesium powder is 75 µm-150 μm, and the particle size of the titanium powder is <75 μm;

[0052] The Ti particle reinforced Mg-based composite material rod prepared by the present invention is packed with soft materials and stored in a clean environment to prevent moisture, sunlight, acid, alkali and salt corrosion. The storage temperature is 20° C. and the relative humidity is ≤10%.

[0053] The implementation effect of the present invention is further illustrated below in conjunction with specific experimental processes. Example 1

[0054] A method for preparing a Ti particle reinforced Mg-based composite material comprises the following steps:

[0055] 1) Weighing the atoms of Mg20Ti1 according to the stoichiometric ratio, with a total mass of 20 g, and then subjecting them to high-energy ball milling to synthesize the MgTi phase with FCC structure; adding stearic acid with a content of 1.2 wt.% of the total mass of Mg and Ti raw materials during the ball milling process; the ball milling speed is 350 rpm, and the ball milling time is 30 hours;

[0056] 2) subjecting the powder obtained in step 1) to spark plasma sintering to obtain a bulk material;

[0057] After the preparation work is completed, the discharge plasma sintering furnace is closed, the vacuum pump is turned on, and the air in the furnace is extracted to make the pressure in the furnace reach 0.1 Pa; the argon gas bottle is turned on, and argon gas is input into the furnace to make the pressure in the furnace reach 1 atmosphere; the plasma discharge heater is turned on, the heating temperature is 560 ℃, and the heat preservation time is 10 min; the heating and pressure are stopped, and the furnace is cooled to room temperature under the protection of argon gas; the argon gas bottle is turned off, the furnace and the mold are opened, and the metal block in the open and close mold is taken out;

[0058] 3) heat treating the sintered block obtained in step 2) to separate Ti particles from the MgTi metastable phase, thereby obtaining a composite material in which fine Ti particles are dispersed in the Mg matrix;

[0059] Heat to 500 °C in a muffle furnace and keep it at this temperature for 60 h;

[0060] 4) hot extruding the composite material obtained in step 3) to obtain a Ti particle reinforced Mg-based composite material rod;

[0061] The extrusion temperature during hot extrusion was 330 °C and the extrusion ratio was 16:1.

[0062] 5) Characterization of phase, microstructure and mechanical properties. The composite material has good metallographic structure density, fine grains, density of 99.5%, Ti particles are evenly distributed in the Mg matrix, the volume fraction of Ti particles is 3.52 v.%, the average particle size is 1.02 μm, and the compressive strength, compressive yield strength and Vickers microhardness (measured by a microhardness tester) are 413 MPa, 406 MPa and 135 HV respectively. 1.0 . Example 2

[0063] A method for preparing a Ti particle reinforced Mg-based composite material comprises the following steps:

[0064] 1) Weighing the atoms of Mg10Ti1 according to the stoichiometric ratio, with a total mass of 20 g, and then subjecting them to high-energy ball milling to synthesize the MgTi phase with FCC structure; adding stearic acid with a content of 1.2 wt.% of the total mass of Mg and Ti raw materials during the ball milling process; the ball milling speed is 350 rpm, and the ball milling time is 35 hours;

[0065] 2) subjecting the powder obtained in step 1) to spark plasma sintering to obtain a bulk material;

[0066] After the preparation work is completed, the discharge plasma sintering furnace is closed, the vacuum pump is turned on, and the air in the furnace is extracted to make the pressure in the furnace reach 0.2 Pa; the argon gas bottle is opened, and argon gas is input into the furnace to make the pressure in the furnace reach 1.1 atmospheres; the plasma discharge heater is turned on, the heating temperature is 560 ℃, and the heat preservation time is 12 min; the heating and pressure are stopped, and the furnace is cooled to room temperature under the protection of argon gas; the argon gas bottle is closed, the furnace and the mold are opened, and the metal block in the open and close mold is taken out;

[0067] 3) heat treating the sintered block obtained in step 2) to separate Ti particles from the MgTi metastable phase, thereby obtaining a composite material in which fine Ti particles are dispersed in the Mg matrix;

[0068] Heat to 500 °C in a muffle furnace and keep it at this temperature for 65 h;

[0069] 4) hot extruding the composite material obtained in step 3) to obtain a Ti particle reinforced Mg-based composite material rod;

[0070] The extrusion temperature during hot extrusion was 340 °C and the extrusion ratio was 16:1.

[0071] 5) Characterization of phase, microstructure and mechanical properties. The composite material has good metallographic structure density, fine grains, density of 99.34%, Ti particles are evenly distributed in the Mg matrix, the volume fraction of Ti particles is 6.77 v.%, the average particle size is 1.15 μm, and the compressive strength, compressive yield strength and Vickers microhardness (measured by microhardness tester) are 468 MPa, 463 MPa and 141 HV respectively. 1.0 . Example 3

[0072] A method for preparing a Ti particle reinforced Mg-based composite material comprises the following steps:

[0073] 1) Weighing the stoichiometric ratio of each atom of Mg7Ti1 to a total mass of 20 g, and then subjecting them to high-energy ball milling to synthesize a MgTi phase with an FCC structure; adding stearic acid with a content of 1.3 wt.% of the total mass of Mg and Ti raw materials during the ball milling process; the ball milling speed is 350 rpm, and the ball milling time is 40 hours;

[0074] 2) subjecting the powder obtained in step 1) to spark plasma sintering to obtain a bulk material;

[0075] After the preparation work is completed, the discharge plasma sintering furnace is closed, the vacuum pump is turned on, and the air in the furnace is extracted to make the pressure in the furnace reach 0.5 Pa; the argon gas bottle is turned on, and argon gas is input into the furnace to make the pressure in the furnace reach 1 atmosphere; the plasma discharge heater is turned on, the heating temperature is 565 ℃, and the heat preservation time is 10 min; the heating and pressure are stopped, and the furnace is cooled to room temperature under the protection of argon gas; the argon gas bottle is turned off, the furnace and the mold are opened, and the metal block in the open and close mold is taken out;

[0076] 3) heat treating the sintered block obtained in step 2) to separate Ti particles from the MgTi metastable phase, thereby obtaining a composite material in which fine Ti particles are dispersed in the Mg matrix;

[0077] Heat to 510 °C in a muffle furnace and keep it at this temperature for 65 h;

[0078] 4) hot extruding the composite material obtained in step 3) to obtain a Ti particle reinforced Mg-based composite material rod;

[0079] The extrusion temperature during hot extrusion was 340 °C and the extrusion ratio was 16:1.

[0080] 5) Characterization of phase, microstructure and mechanical properties. The composite material has good metallographic structure density, fine grains, density of 99.05%, Ti particles are evenly distributed in the Mg matrix, the volume fraction of Ti particles is 9.5 v.%, the average particle size is 1.44 μm, the compressive strength, compressive yield strength and Vickers microhardness are 496 MPa, 487 MPa and 157 HV respectively. 1.0 . Example 4

[0081] A method for preparing a Ti particle reinforced Mg-based composite material comprises the following steps:

[0082] 1) Weighing the stoichiometric ratio of each atom of Mg5Ti1 to a total mass of 20 g, and then subjecting them to high-energy ball milling to synthesize a MgTi phase with an FCC structure; adding stearic acid with a content of 1.4 wt.% of the total mass of Mg and Ti raw materials during the ball milling process; the ball milling speed is 350 rpm, and the ball milling time is 35 hours;

[0083] 2) subjecting the powder obtained in step 1) to spark plasma sintering to obtain a bulk material;

[0084] After the preparation work is completed, the discharge plasma sintering furnace is closed, the vacuum pump is turned on, and the air in the furnace is extracted to make the pressure in the furnace reach 0.5 Pa; the argon gas bottle is turned on, and argon gas is input into the furnace to make the pressure in the furnace reach 1 atmosphere; the plasma discharge heater is turned on, the heating temperature is 570 ℃, and the heat preservation time is 10 min; the heating and pressure are stopped, and the furnace is cooled to room temperature under the protection of argon gas; the argon gas bottle is turned off, the furnace and the mold are opened, and the metal block in the open and close mold is taken out;

[0085] 3) heat treating the sintered block obtained in step 2) to separate Ti particles from the MgTi metastable phase, thereby obtaining a composite material in which fine Ti particles are dispersed in the Mg matrix;

[0086] The temperature was raised to 515 °C in a muffle furnace and kept at this temperature for 70 h;

[0087] 4) hot extruding the composite material obtained in step 3) to obtain a Ti particle reinforced Mg-based composite material rod;

[0088] The extrusion temperature during hot extrusion was 350 °C and the extrusion ratio was 16:1.

[0089] 5) Characterization of phase, microstructure and mechanical properties. The composite material has good metallographic structure density, fine grains, density of 99.05%, Ti particles are evenly distributed in the Mg matrix, the volume fraction of Ti particles is 12.7 v.%, the average particle size is 1.85 μm, the compressive strength, compressive yield strength and Vickers microhardness are 530 MPa, 490 MPa and 178 HV respectively. 1.0 . Example 5

[0090] A method for preparing a Ti particle reinforced Mg-based composite material comprises the following steps:

[0091] 1) Weighing the Mg2Ti1 atoms according to the stoichiometric ratio, with a total mass of 20 g, and then subjecting them to high-energy ball milling to synthesize the MgTi phase with FCC structure; adding stearic acid with a content of 1.5 wt.% of the total mass of Mg and Ti raw materials during the ball milling process; the ball milling speed is 350 rpm, and the ball milling time is 40 hours;

[0092] 2) subjecting the powder obtained in step 1) to spark plasma sintering to obtain a bulk material;

[0093] After the preparation work is completed, the discharge plasma sintering furnace is closed, the vacuum pump is turned on, and the air in the furnace is extracted to make the pressure in the furnace reach 0.1 Pa; the argon gas bottle is turned on, and argon gas is input into the furnace to make the pressure in the furnace reach 1 atmosphere; the plasma discharge heater is turned on, the heating temperature is 570 ℃, and the heat preservation time is 15 min; the heating and pressure are stopped, and the furnace is cooled to room temperature under the protection of argon gas; the argon gas bottle is turned off, the furnace and the mold are opened, and the metal block in the open and close mold is taken out;

[0094] 3) heat treating the sintered block obtained in step 2) to separate Ti particles from the MgTi metastable phase, thereby obtaining a composite material in which fine Ti particles are dispersed in the Mg matrix;

[0095] The temperature was raised to 520 °C in a muffle furnace and kept at this temperature for 70 h;

[0096] 4) hot extruding the composite material obtained in step 3) to obtain a Ti particle reinforced Mg-based composite material rod;

[0097] The extrusion temperature during hot extrusion was 360 °C and the extrusion ratio was 16:1.

[0098] 5) Characterization of phase, microstructure and mechanical properties. The composite material has good metallographic structure density, fine grains, density of 99.05%, Ti particles are evenly distributed in the Mg matrix, the volume fraction of Ti particles is 26.4 v.%, the average particle size is 1.87 μm, the compressive strength, compressive yield strength and Vickers microhardness are 585 MPa, 562 MPa and 207 HV respectively. 1.0 .

[0099] The present invention detects, analyzes and characterizes the morphology, color, metallographic structure and mechanical properties of the prepared Ti particle reinforced Mg-based composite material rod;

[0100] Taking the material with Mg10Ti1 as an example, the phase composition analysis is performed using an X-ray diffractometer; Figure 1 As shown in the figure, it can be seen that the ball-milled powder is composed of Mg phase and MgTi phase with FCC structure, and does not contain pure Ti phase;

[0101] Taking the material with Mg10Ti1 composition as an example, metallographic structure analysis was performed using an optical microscope; Figure 2 As shown in the figure, it can be seen that fine dispersed Ti particles are distributed on the Mg matrix.

[0102] Taking the material with Mg10Ti1 composition as an example, the morphology analysis was performed using a transmission electron microscope; Figure 3 As shown in the figure, it can be seen that there are nano-scale Ti particles with a size of about 15-30 nm.

[0103] Taking the material with Mg10Ti1 composition as an example, the Ti particle size and distribution in the composite material were analyzed using optical microscopy and transmission electron microscopy; Figure 4 As shown in Figure 2, the size distribution of Ti particles in the composite material can be seen. Figure 2 , Figure 3 and Figure 4 It can be seen that the Ti particles in the composite material with Mg10Ti1 component are small and evenly distributed in the Mg matrix, with an average particle size of 1.15 μm.

[0104] Taking the material with Mg10Ti1 composition as an example, the mechanical properties analysis was carried out using an electronic universal testing machine; Figure 5 As shown in the figure, it can be seen that the compressive strength and compressive yield strength of the Ti particle reinforced Mg-based composite rod are 468 MPa and 463 MPa, respectively, which are much higher than the compression properties of pure magnesium.

[0105] Conclusion: The Ti particle reinforced Mg-based composite material is a silvery white block with a density of 99-99.5%. The Ti particles are evenly distributed in the Mg matrix. The volume fraction of the Ti particles is 3-30v.%, and the average particle size is 1-2 μm. The compressive strength, compressive yield strength and Vickers microhardness of the composite material obtained in the embodiment are 400-600 MPa, 400-600 MPa and 130-210 HV, respectively. 1.0 .

Claims

1. A method for preparing a Ti particle reinforced Mg-based composite material, characterized in that The following steps are involved: (1) Press Mg x Ti y Mg powder and Ti powder are weighed in each atomic stoichiometric ratio, and then subjected to high-energy ball milling to synthesize MgTi metastable phase; x is 2-20, and y is 1; (2) subjecting the powder obtained in step (1) to spark plasma sintering to obtain a bulk material; (3) heat treating the sintered block obtained in step (2) to separate Ti particles from the MgTi metastable phase, thereby obtaining a composite material in which fine Ti particles are dispersed in the Mg matrix; The heat treatment process is as follows: the surface of the sintered metal block is polished clean, and then tightly wrapped with tin foil to avoid contact with air; then the metal block is placed in a muffle furnace, the power of the muffle furnace is turned on, the temperature is raised to 500-520 ° C, and the temperature is kept for 60-70 hours; the power of the muffle furnace is turned off, the temperature is cooled to room temperature, and the metal block is taken out; (4) The composite material obtained in step (3) is hot extruded to obtain a Ti particle reinforced Mg-based composite material rod.

2. The method for preparing a Ti particle reinforced Mg-based composite material according to claim 1, characterized in that: In step (1), the FCC structured MgTi metastable phase is synthesized by high energy ball milling. x Ti y The stoichiometric ratios of each atom were weighed, and 1-1.5 wt.% of stearic acid was added to the total mass of Mg and Ti raw materials to prevent cold welding during the subsequent ball milling process.

3. The method for preparing the Ti particle reinforced Mg-based composite material according to claim 2, characterized in that: The prepared powder was placed in an agate ball mill, and then three agate balls of different sizes were loaded into the ball mill. The diameters of the agate balls were Φ5 mm, Φ8 mm and Φ10 mm, respectively, and the ball mass ratio was 2:5:

3.

4. The method for preparing a Ti particle reinforced Mg-based composite material according to claim 2, characterized in that: The specific ball milling process is as follows: ① Seal the ball mill jar and fill it with argon to protect the powder from contacting the air during the ball milling process; ② Fix the ball mill jar on the ball mill; ③ Turn on the ball mill, the ball milling speed is 350 rpm, and the ball milling time is 30-40 hours; ④ After the ball milling is completed, turn off the ball mill, take out the ball mill jar, open it in the glove box, take out the powder, and seal it for later use.

5. The method for preparing a Ti particle reinforced Mg-based composite material according to claim 1, characterized in that: Step (2) the spark plasma sintering process is completed under argon protection, plasma discharge heating, pressure motor pressure, and external water circulation cooling; the specific process is: In a glove box, the ball milled powder is loaded into a sintering mold made of graphite with an inner diameter of Φ40 mm. Open the spark plasma sintering furnace, place the graphite mold vertically on the workbench in the furnace chamber, and fix it; Close the spark plasma sintering furnace, turn on the vacuum pump, extract the air in the furnace to make the pressure in the furnace reach 0.1-1 Pa; open the argon bottle, input argon into the furnace to make the pressure in the furnace reach 1-1.1 atmospheres; turn on the plasma discharge heater, heating temperature 560-570 ℃, insulation time 10-15 min; stop heating and pressurizing, cool to room temperature with the furnace under argon protection; close the argon bottle, open the furnace, open the mold, and take out the metal block in the mold.

6. The method for preparing a Ti particle reinforced Mg-based composite material according to claim 1, characterized in that: The hot extrusion process of step (4) is as follows: placing a metal block on a steel flat plate, and polishing the periphery and the front and back surfaces of the metal block with 400-grit sandpaper to make it smooth; placing the polished metal block in a steel extrusion die; starting the extruder and performing hot extrusion at an extrusion temperature of 330-360°C and an extrusion ratio of 16:

1. After the extrusion is completed, a rod with a diameter of Φ10 mm is obtained.

7. The method for preparing a Ti particle reinforced Mg-based composite material according to claim 1, characterized in that: The particle size of magnesium powder is 75 µm-150 μm, and the particle size of titanium powder is less than 75 μm.

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