A magnesium-based composite material, its preparation method and application

Abstract

The present invention belongs to the field of composite materials, and specifically discloses a magnesium-based composite material, a preparation method thereof and an application. The preparation method includes the following steps: S1: Heating magnesium-based alloy particles to a semi-solid state, and then mixing them with metal reinforcing particles to obtain a semi-solid mixed slurry; S2: Pressing and extruding the semi-solid mixed slurry to form the magnesium-based composite material. In the preparation method of the present invention, by mixing metal reinforcing particles with a semi-solid magnesium-based alloy slurry and extruding and forming under pressure, the entire preparation method can be continuously produced, with a short production process and high efficiency. At the same time, the semi-solid extrusion method is adopted, so that the obtained magnesium-based composite material has the advantages of being dense, free of porosity defects, uniform distribution of metal reinforcing particles, and relatively high mechanical strength.

Description

Technical Field

[0001] The present invention belongs to the field of composite materials, and particularly relates to a magnesium-based composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Magnesium alloys are currently the most promising lightweight materials, but their disadvantages of low strength, low plasticity, and poor corrosion resistance limit their wide application. By adding rare earth elements such as Y and Ga to rare earths, the strength of magnesium alloys can be significantly improved, but it is difficult to simultaneously improve toughness, corrosion resistance, etc. Magnesium-based composite materials prepared using metal particles such as Ti and TC4 as reinforcement can combine the advantages of the reinforcement and the matrix magnesium alloy to obtain a new material with good comprehensive properties such as strength, toughness, and corrosion resistance, and thus have received extensive attention and research in the industry and have great market potential.

[0003] The preparation methods of metal particle-reinforced magnesium-based composite materials mainly include vacuum stirring casting method and powder metallurgy method. The equipment used in the vacuum stirring casting method is a vacuum stirring furnace. Under vacuum or inert gas protection, the reinforcement is added to the magnesium alloy melt, and the slurry is stirred evenly by mechanical or electromagnetic stirring and then cast. The advantage of the stirring casting method is that the structure of the vacuum stirring furnace is simple and the production cost is low. However, rare earth magnesium alloys have complex compositions and high melt viscosities. After adding reinforcement particles, the viscosity further increases, and the ingot is prone to porosity defects, seriously affecting the mechanical properties of the material.

[0004] [[ID=ID=14]]The powder metallurgy method uses a powder mixer and a hot press to mix the reinforcement particles and magnesium alloy powder evenly and then sinter to make a composite material product. Its advantages are that the reinforcement is evenly distributed and near-net shaping of the casting can be achieved. However, the production efficiency is low and the manufacturing cost is high. And due to the influence of the hot pressing equipment and the mold, the product structure is limited. Summary of the Invention

[0005] In order to overcome at least one of the above problems existing in the prior art, one of the purposes of the present invention is to provide a preparation method of a magnesium-based composite material.

[0006] Another purpose of the present invention is to provide a magnesium-based composite material.

[0007] Another purpose of the present invention is to provide a screw extruder.

[0008] Another purpose of the present invention is to provide the application of the above preparation method of the magnesium-based composite material and / or the above magnesium-based composite material in the preparation of electronic equipment.

[0009] In order to achieve the above purposes, the technical solutions adopted by the present invention are as follows:

[0010] The first aspect of the present invention provides a preparation method of a magnesium-based composite material, including the following steps:

[0011] S1: Heat the magnesium-based alloy particles to the semi-solid state, and then mix them with metal reinforcement particles to obtain a semi-solid mixed slurry;

[0012] S2: Press and extrude the semi-solid mixed slurry to form the magnesium-based composite material.

[0013] Preferably, step S1 includes the following steps:

[0014] S11: Heat the magnesium-based alloy particles to the semi-solid state in a screw extruder to obtain semi-solid magnesium-based alloy;

[0015] S12: Mix the metal reinforcement particles with the semi-solid magnesium-based alloy in a screw extruder to obtain a semi-solid mixed slurry.

[0016] Preferably, the screw rotation speed of the screw extruder is 300 - 500 r / min.

[0017] Preferably, the heating temperature in step S11 is 560 - 650 °C.

[0018] Preferably, step S2 is specifically: Press and extrude the semi-solid mixed slurry, and solidify and form it through an extrusion die to obtain the magnesium-based composite material.

[0019] Preferably, the extrusion speed of the press and extrusion step is 10 - 100 mm / min.

[0020] Preferably, the extrusion pressure of the press and extrusion step is 60 - 100 MPa.

[0021] Preferably, the temperature of the extrusion die is 350 - 420 °C.

[0022] Preferably, the metal reinforcement particles include at least one of Ti, TC4, Mn, titanium metal compounds, and manganese metal compounds.

[0023] Preferably, the particle size of the metal reinforcement particles is 0.5 - 30 μm.

[0024] Preferably, the magnesium-based alloy particles are irregular in shape or cuboid.

[0025] Preferably, the length of the magnesium-based alloy particles is 0.5 - 10 mm, and the cross-sectional dimension is 0.25 - 4 mm 2 。

[0026] Preferably, the magnesium-based alloy is at least one of a cast magnesium alloy and a wrought magnesium alloy. The present invention can use either a cast magnesium alloy or a wrought magnesium alloy as the matrix, and can achieve continuous production of composite materials with different shapes.

[0027] The second aspect of the present invention provides a magnesium-based composite material prepared by the preparation method described in the first aspect of the present invention. The mass percentage of the metal reinforcing particles in the magnesium-based composite material is 0.5-35%.

[0028] The third aspect of the present invention provides a screw extruder for implementing the preparation method of the magnesium-based composite material described in the first aspect of the present invention. The screw extruder includes a screw rotation mechanism, a screw, a barrel, a pressing pad, a hopper A, a hopper B, a pressure system, a heater, and an extrusion die; the output end of the screw rotation mechanism is connected to the screw; the screw and the pressing pad are both located in the barrel, and the extrusion die is arranged at the outlet of the barrel; hopper A and hopper B are arranged on the barrel; the distance between hopper A and the extrusion die is less than the distance between hopper B and the extrusion die; a heater is arranged on the barrel; the pressure system provides pressure for the pressing pad.

[0029] Preferably, the heater is a segmented electric heater. The use of a segmented electric heater for the heater in the present invention can achieve segmented control of the temperature of the barrel, so as to adjust the temperature of the barrel in segments according to the extrusion requirements.

[0030] The fourth aspect of the present invention provides the application of the preparation method of the magnesium-based composite material described in the first aspect of the present invention and / or the magnesium-based composite material described in the second aspect of the present invention in the preparation of electronic equipment.

[0031] Preferably, the electronic equipment includes 3C electronic products, drones, automobiles, ships, aerospace equipment, marine equipment or engineering equipment.

[0032] The beneficial effects of the present invention are as follows: In the preparation method of the present invention, the metal reinforcing particles are mixed with the semi-solid magnesium-based alloy slurry and extruded and formed under pressure. The entire preparation method can be continuously produced, with a short production process and high efficiency. At the same time, the semi-solid extrusion method is adopted, so that the prepared magnesium-based composite material has the advantages of being dense, without porosity defects, uniform distribution of metal reinforcing particles, and high mechanical strength.

[0033] Specifically, in the preparation method of the present invention, the metal reinforcing particles are added into the semi-solid magnesium-based alloy slurry online, mixed evenly under the shearing and stirring action of the screw, and extruded and formed under pressure. The production process is short, the efficiency is high, continuous production can be realized, the prepared magnesium-based composite material has a dense structure, combines the characteristics of casting structure and deformed structure, the metal reinforcing particles are evenly distributed, and the mechanical properties are significantly higher than those of the composite material prepared by stir casting. In addition, the entire preparation process of the preparation method of the present invention does not require inert gas protection and belongs to a short-process green manufacturing technology. Description of the Drawings

[0034] Figure 1 It is a schematic structural diagram of the semi-solid squeeze casting device adopted in Example 1.

[0035] Figure 2 It is a physical picture of the Mg-9Gd-4Y-1Zn magnesium alloy particles in Example 1.

[0036] Figure 3 It is a cross-sectional SEM image of the magnesium matrix composite in Example 1.

[0037] Figure 4 It is a longitudinal-sectional SEM image of the magnesium matrix composite in Example 1. Specific implementation manners

[0038] The following further elaborates on the specific implementation of the present invention in conjunction with the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that for the processes not specifically described in detail below, those skilled in the art can implement or understand them with reference to the prior art. Reagents or instruments without indicating the manufacturer can be obtained as conventional products through commercial purchase.

[0039] In some embodiments of the present invention, a method for preparing a magnesium matrix composite is provided, including the following steps:

[0040] Heat the magnesium matrix alloy particles to a semi-solid state, and then mix them with metal reinforcing particles to obtain a semi-solid mixed slurry;

[0041] Press and extrude the semi-solid mixed slurry into a mold to obtain the magnesium matrix composite.

[0042] In some embodiments of the present invention, the method for preparing the magnesium matrix composite provided by the present invention includes the following steps:

[0043] Heat the magnesium matrix alloy particles to a semi-solid state in a screw extruder to obtain a semi-solid magnesium matrix alloy;

[0044] Mix the metal reinforcing particles with the semi-solid magnesium matrix alloy in the screw extruder to obtain a semi-solid mixed slurry;

[0045] Press and extrude the semi-solid mixed slurry, and solidify and form it through an extrusion die to obtain the magnesium matrix composite.

[0046] In some embodiments of the present invention, the magnesium matrix alloy particles are processed into particulate materials by using a granulator to process magnesium matrix alloy ingots.

[0047] In some embodiments of the present invention, the screw speed of the screw extruder is 300 - 500 r / min. In some specific embodiments of the present invention, the screw speed of the screw extruder can be 310 r / min, 320 r / min, 330 r / min, 340 r / min, 350 r / min, 360 r / min, 370 r / min, 380 r / min, 390 r / min, 400 r / min, 410 r / min, 420 r / min, 430 r / min, 440 r / min, 450 r / min, 460 r / min, 470 r / min, 480 r / min, 490 r / min, 500 r / min. The present invention uses a screw extruder with the above speed to mix metal reinforcing particles and a semi-solid magnesium alloy matrix. Under the rotational stirring and shearing action of the screw, the mixing effect is good, and the uniform dispersion of the metal reinforcing particles can be achieved. If the rotational speed of the screw is too slow, the shear force is small and the stirring effect is poor, which is not conducive to the uniform distribution of the metal reinforcing particles. If the rotational speed of the screw is too fast, high requirements are imposed on the material, stiffness, rotational mechanism power, and stability of the screw, and the production cost increases.

[0048] In some embodiments of the present invention, the heating temperature for heating the magnesium-based alloy particles to a semi-solid state is 560 - 650 °C; in some specific embodiments of the present invention, the heating temperature can be 560 °C, 570 °C, 580 °C, 590 °C, 600 °C, 610 °C, 620 °C, 630 °C, 640 °C, 650 °C. If the heating temperature is too low, the melt viscosity is too high, which is not conducive to extrusion molding; if the heating temperature is too high, the metal reinforcing particles are prone to sedimentation, affecting the uniform distribution of the metal reinforcing particles.

[0049] In some embodiments of the present invention, the extrusion speed in the pressure extrusion step is 10 - 100 mm / min; in some specific embodiments of the present invention, the extrusion speed can be 10 mm / min, 15 mm / min, 20 mm / min, 25 mm / min, 30 mm / min, 35 mm / min, 40 mm / min, 45 mm / min, 50 mm / min, 55 mm / min, 60 mm / min, 65 mm / min, 70 mm / min, 75 mm / min, 80 mm / min, 85 mm / min, 90 mm / min, 95 mm / min, 100 mm / min. If the extrusion speed is too slow, the production efficiency is low, and the semi-solid mixed slurry is prone to solidify at the entrance of the extrusion die, resulting in extrusion failure; if the extrusion speed is too fast, the obtained magnesium-based composite material is prone to hole defects, reducing the mechanical properties of the material, and at the same time, defects such as cracks are likely to occur on the surface.

[0050] In some embodiments of the present invention, the extrusion pressure in the pressure extrusion step is 60 - 100 MPa; in some specific embodiments of the present invention, the extrusion pressure can be 60 MPa, 65 MPa, 70 MPa, 75 MPa, 80 MPa, 85 MPa, 90 MPa, 95 MPa, 100 MPa. If the extrusion pressure is too small, the extrusion speed is slow, and the density of the prepared magnesium-based composite material decreases; if the extrusion pressure is too large, it is easy to cause the solidification position of the semi-solid mixed slurry to shift outwards to the outlet of the extrusion die, resulting in extrusion failure, or insufficient extrusion deformation of the magnesium-based composite material, and the product shape consistency of the prepared magnesium-based composite material is poor.

[0051] In some embodiments of the present invention, the temperature of the extrusion die is 350 - 420 °C; in some specific embodiments of the present invention, the temperature of the extrusion die can be 350 °C, 355 °C, 360 °C, 365 °C, 370 °C, 375 °C, 380 °C, 385 °C, 390 °C, 395 °C, 400 °C, 405 °C, 410 °C, 415 °C, 420 °C. If the temperature of the extrusion die is too low, extrusion failure is likely to occur and it is difficult to form the composite material; if the temperature of the extrusion die is too high, transverse cracks are likely to appear in the composite material and the surface quality is poor.

[0052] In some embodiments of the present invention, the shape of the extrusion die can be rod-shaped, tubular, plate-strip-shaped or other irregular shapes.

[0053] In some embodiments of the present invention, the metal reinforcing particles include at least one of Ti, TC4, Mn, titanium metal compounds, and manganese metal compounds. In some embodiments of the present invention, the titanium metal compounds include at least one of titanium oxide, titanium nitride, and titanium boride; in some embodiments of the present invention, the manganese metal compounds include at least one of manganese oxide and manganese nitride. The metal reinforcing particles in the present invention do not chemically react with the magnesium-based alloy matrix and have a very small solid solubility in the magnesium-based alloy matrix.

[0054] In some embodiments of the present invention, the particle size of the metal reinforcing particles is 0.5 - 30 μm, and in some specific embodiments of the present invention, the particle size of the metal reinforcing particles can be 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm.

[0055] In some embodiments of the present invention, the metal reinforcing particles are spherical or quasi-spherical.

[0056] In some embodiments of the present invention, the magnesium-based alloy particles are irregular in shape or cuboid; in some embodiments of the present invention, the length of the magnesium-based alloy particles is 0.5-10 mm, and the cross-sectional size is 0.25-4 mm 2 ; in some embodiments of the present invention, the length of the magnesium-based alloy particles can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm; in some embodiments of the present invention, the cross-sectional size of the magnesium-based alloy particles can be 0.25 mm 2 , 1 mm 2 , 2 mm 2 , 3 mm 2 , 4 mm 2 .

[0057] In some embodiments of the present invention, the magnesium-based alloy is at least one of a cast magnesium alloy and a wrought magnesium alloy. The present invention can use either a cast magnesium alloy or a wrought magnesium alloy as the matrix, enabling the continuous production of composite materials with different shapes.

[0058] In some embodiments of the present invention, the present invention also provides a magnesium-based composite material prepared by the above preparation method, and the mass percentage of the metal reinforcing particles in the magnesium-based composite material is 0.5-35%.

[0059] In some embodiments of the present invention, the present invention also provides a screw extruder, the structural schematic diagram of which is as Figure 1 shown, including a pressure system 1, a hopper B 2, a heater 3, a hopper A 4, an extrusion die 5, an extruded composite material 6, a semi-solid mixed slurry 7, a extrusion pad 8, a barrel 9, a screw 10, a screw rotation mechanism 11; the output end of the screw rotation mechanism 11 is connected to the screw 10; the screw 10 and the extrusion pad 8 are both arranged in the barrel 9, the barrel 9 is filled with the semi-solid mixed slurry 7, the inlets of the barrel 9 are respectively communicated with the hopper B 2 and the hopper A 4; the hopper A 4 is located between the hopper B 2 and the extrusion die 5, the outside of the barrel 9 is provided with a heater 3, the heater 3 can be heated in sections, the outlet of the barrel 9 is provided with an extrusion die 5, and a pressure system 1 is arranged on the semi-solid squeeze casting device, and the pressure system 1 is used to provide pressure for the extrusion pad 8, and the extrusion pad 8 extrudes the semi-solid mixed slurry 7 under the pressure provided by the pressure system 1, so that the semi-solid mixed slurry 7 is extruded through the extrusion die 5 and cooled and formed into the extruded composite material 6.

[0060] The screw rod 10 in the present invention can rotate but does not displace in the horizontal direction. During use, when the screw rod 10 advances the magnesium alloy particles to the metal reinforcement particle addition area, it has reached the semi-solid state temperature. With the addition of the metal reinforcement particles, if the melt temperature drops significantly, the temperature needs to be readjusted to ensure that the slurry is in the semi-solid state and has good fluidity for extrusion molding. The pressure system 1 can continuously apply pressure to the extrusion pad 8. Under the pressure of the extrusion pad 8, the slurry is extruded into the extrusion die 5. The semi-solid mixed slurry 7 solidifies and forms under the combined action of the pressure provided by the pressure system 1 and the deformation pressure of the extrusion die 5, avoiding the generation of pore defects such as porosity, and making the obtained magnesium matrix composite material have a high density and mechanical strength.

[0061] In some embodiments of the present invention, the method for preparing the magnesium matrix composite material provided by the present invention includes the following steps:

[0062] 1) Using a granulator to process a magnesium-based alloy ingot into magnesium-based alloy particles;

[0063] 2) Feeding the magnesium-based alloy particles into the barrel 9 through the hopper B2, and transmitting them towards the extrusion die 5 under the action of the screw rod 10. The barrel 9 is heated by the heater 3 to heat the magnesium-based alloy particles to the semi-solid state to obtain a semi-solid magnesium alloy matrix;

[0064] 3) The dissimilar metal reinforcement particles enter the barrel 9 through the hopper A4 and are fully mixed with the semi-solid magnesium alloy matrix under the rotational stirring action of the screw rod 10 to obtain a semi-solid mixed slurry 7 with uniform particle distribution; the rotation of the screw rod 10 exerts extrusion on the particles, and the particles move in the barrel 9 to obtain mixing.

[0065] 4) The pressure system 1 provides pressure, and the semi-solid mixed slurry 7 is extruded through the extrusion die 5 under the pressure of the extrusion pad 8 to achieve continuous extrusion.

[0066] The following further elaborates on the implementation of the present invention in combination with specific embodiments:

[0067] Example 1

[0068] This example provides a semi-solid extrusion preparation method for a magnesium matrix composite material, which includes the following steps:

[0069] (1) Using a granulator to process a commercially available Mg-9Gd-4Y-1Zn ingot into irregular long-strip-shaped Mg-9Gd-4Y-1Zn magnesium alloy particles (the physical diagram is as Figure 2As shown, particles are added into the barrel 9 through the hopper B2 and are conveyed towards the extrusion die 5 under the action of the screw 10. The rotational speed of the screw 10 is 350 r / min, and it is heated to the semi-solid temperature range of 585 - 600 °C by the heater 3 outside the barrel 9 to obtain the semi-solid Mg-9Gd-4Y-1Zn slurry.

[0070] (2) Dry Ti particles with an average particle size of 10 μm are pre-loaded into the hopper A4. During the preparation process, the valve below the hopper A4 is opened, the feeding speed is adjusted, and the Ti particles are added into the semi-solid Mg-9Gd-4Y-1Zn slurry and are mixed evenly under the shearing and stirring action of the screw 10 to become a semi-solid mixed slurry.

[0071] (3) The extrusion die 5 is preheated to 400 °C. The above semi-solid mixed slurry is extruded at an extrusion speed of 60 mm / min and an extrusion pressure of 70 MPa to obtain the magnesium-based composite material in this example, that is, a Ti particle-reinforced Mg-9Gd-4Y-1Zn rod-shaped composite material profile.

[0072] In the magnesium-based composite material of this example, the mass percentage of Ti particles is 5 wt%, and the magnesium-based composite material is a rod-shaped composite material with a diameter of 40 mm.

[0073] Example 2

[0074] This example provides a semi-solid extrusion preparation method for a magnesium-based composite material, which includes the following steps:

[0075] (1) Using a granulator, commercially available AZ91D ingots are processed into irregular long-strip-shaped AZ91D magnesium alloy particles. The particles are added into the barrel 9 through the hopper B2 and are conveyed towards the extrusion die 5 under the action of the screw 10. The rotational speed of the screw is 400 r / min, and it is heated to the semi-solid temperature range of 580 - 590 °C by the heater outside the barrel.

[0076] (2) Dry TC4 particles with an average particle size of 15 μm are pre-loaded into the hopper A4. During the preparation process, the valve below the hopper A4 is opened, the feeding speed is adjusted, and the TC4 particles are added into the semi-solid AZ91D slurry and are mixed evenly under the shearing and stirring action of the screw 10 to become a semi-solid mixed slurry.

[0077] (3) The extrusion die 5 is preheated to 380 °C. The above semi-solid mixed slurry is extruded at an extrusion speed of 50 mm / min and an extrusion pressure of 70 MPa to obtain the magnesium-based composite material in this example, that is, a Ti particle-reinforced AZ91D rod-shaped composite material.

[0078] Comparative Example 1

[0079] This example provides an extrusion preparation method for a magnesium-based composite material, which includes the following steps:

[0080] (1) Add irregular long-strip Mg-9Gd-4Y-1Zn magnesium alloy particles into the barrel 9 through hopper B2, and transfer them towards the extrusion die 5 under the action of the screw 10. The rotation speed of the screw 10 is 350 r / min, and heat them to the temperature range of 640 - 650 °C through the heater 3 outside the barrel 9 to obtain a liquid Mg-9Gd-4Y-1Zn slurry.

[0081] (2) Pre-load dry Ti particles with an average particle size of 10 μm into hopper A4. During the preparation process, open the valve below hopper A4, adjust the feeding speed, add the Ti particles into the above liquid Mg-9Gd-4Y-1Zn slurry, and mix them evenly under the shearing and stirring action of the screw 10 to form a molten composite material slurry.

[0082] (3) Preheat the extrusion die 5 to 400 °C, and extrude the above molten composite material slurry at an extrusion speed of 60 mm / min and an extrusion pressure of 70 MPa to obtain the magnesium-based composite material in this example, that is, a Ti particle-reinforced Mg-9Gd-4Y-1Zn rod-shaped composite material.

[0083] In the magnesium-based composite material of this example, the addition amount of Ti particles is 5 wt% of the mass of the Mg-9Gd-4Y-1Zn magnesium alloy particles, and the magnesium-based composite material is a rod-shaped composite material with a diameter of 40 mm.

[0084] Comparative Example 2

[0085] The difference between the extrusion preparation method of the magnesium-based composite material in this example and that in Example 1 is only that: the rotation speed of the screw 10 in step (1) of this example is 200 r / min.

[0086] Comparative Example 3

[0087] The difference between the extrusion preparation method of the magnesium-based composite material in this example and that in Example 1 is only that: the extrusion speed of the semi-solid mixed slurry in step (3) of this example is 110 mm / min.

[0088] Comparative Example 4

[0089] The difference between the extrusion preparation method of the magnesium-based composite material in this example and that in Example 1 is only that: in step (1) of this example, the irregular long-strip Mg-9Gd-4Y-1Zn magnesium alloy particles are heated to the liquid temperature range of 660 - 670 °C through the heater outside the barrel.

[0090] Comparative Example 5

[0091] The difference between the extrusion preparation method of the magnesium-based composite material in this example and that in Example 1 is only that: the extrusion pressure of the semi-solid mixed slurry in step (3) of this example is 50 MPa.

[0092] Comparative Example 6

[0093] The difference between the extrusion preparation method of the magnesium-based composite material in this example and that in Example 2 is only that: in step (1) of this example, the irregular long strip-shaped AZ91D magnesium alloy particles are heated to the liquid temperature range of 620 - 630 °C through a heater outside the barrel.

[0094] Comparative Example 7

[0095] The difference between the extrusion preparation method of the magnesium-based composite material in this example and that in Example 2 is only that: in step (3) of this example, the extrusion die 5 is preheated to 450 °C.

[0096] Comparative Example 8

[0097] The difference between the extrusion preparation method of the magnesium-based composite material in this example and that in Example 2 is only that: in step (3) of this example, the extrusion die 5 is preheated to 300 °C.

[0098] The magnesium-based composite materials prepared in the examples and comparative examples were subjected to performance tests. Among them, the test standards for the tensile strength and yield strength at room temperature refer to "GB / T16865 - 2013", and the test standard for the elongation after fracture refers to "GB / T16865 - 2013". The test results are shown in Table 1 below.

[0099] Table 1 Room temperature performance test results of magnesium-based composite materials

[0100]

[0101] As can be seen from Table 1, the method of preparing magnesium-based composite materials by semi-solid extrusion in the present invention can improve the tensile strength and yield strength of magnesium-based composite materials at room temperature.

[0102] The SEM images of the cross-section and longitudinal section of the magnesium-based composite material prepared in Example 1 were respectively tested by a scanning electron microscope. The specific test results are respectively as Figure 3 and Figure 4 shown. From Figure 3 and Figure 4 it can be seen that the Ti particles are evenly distributed in the Mg-9Gd-4Y-1Zn matrix, and under the action of the extrusion pressure, the Ti particles are distributed along the fiber structure in the direction of squeeze casting.

[0103] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A preparation method of a magnesium-based composite material, characterized in that: It includes the following steps: S1: Heat the magnesium-based alloy particles to a semi-solid state in a screw extruder to obtain a semi-solid magnesium-based alloy; mix the metal reinforcement particles with the semi-solid magnesium-based alloy in the screw extruder to obtain a semi-solid mixed slurry; S2: Pressurize and extrude the semi-solid mixed slurry, and cure and form it through an extrusion die to obtain the magnesium-based composite material; The screw rotation speed of the screw extruder is 300 - 500 r / min; The extrusion speed of the pressurized extrusion step is 10 - 100 mm / min; The extrusion pressure of the pressurized extrusion step is 60 - 100 MPa; The temperature of the extrusion die is 350 - 420 °C; The metal reinforcement particles include at least one of Ti, TC4, and titanium metal compounds.

2. The preparation method of the magnesium-based composite material according to claim 1, wherein: The heating temperature is 560 - 650 °C.

3. The preparation method of the magnesium-based composite material according to claim 1, wherein: The particle size of the metal reinforcement particles is 0.5 - 30 μm.

4. The preparation method of the magnesium-based composite material according to claim 1, characterized in that: The length of the magnesium-based alloy particles is 0.5 to 10 mm, and the cross-sectional size is 0.25 to 4 mm 2 .

5. The preparation method of the magnesium-based composite material according to claim 1, characterized in that: The magnesium-based alloy is at least one of a cast magnesium alloy and a wrought magnesium alloy.

6. A magnesium-based composite material, characterized in that: Prepared by the preparation method according to any one of claims 1 - 5, the mass percentage of the metal reinforcement particles in the magnesium-based composite material is 0.5 - 35%.

7. Use of the preparation method of the magnesium-based composite material according to any one of claims 1 - 5 or the magnesium-based composite material according to claim 6 in the preparation of electronic equipment.

8. The application according to claim 7, wherein: The electronic equipment includes 3C electronic products, drones, automobiles, ships, aerospace equipment, and marine equipment.

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