Corrosion-resistant rare earth magnesium-based composite material as well as preparation method and application thereof

Abstract

The invention belongs to the field of materials, and particularly relates to a corrosion-resistant rare earth magnesium-based composite material and a preparation method and application thereof. The preparation raw materials of the rare earth magnesium-based composite material comprise a magnesium base material and reinforced particles, the reinforced particles comprise titanium particles and aluminum coating layers coating the surfaces of the titanium particles, and the mass ratio of the aluminum coating layers to the titanium particles is (5-10): 100; the magnesium base material is an Mg-RE-Zn series alloy; the RE is selected from at least one of Gd and Y; in the magnesium base material, the mass percent of Gd is less than or equal to 11%, and / or the mass percent of Y is less than or equal to 6%. The rare earth magnesium-based composite material disclosed by the invention has corrosion potential and corrosion current which are close to those of a magnesium base material, so that the rare earth magnesium-based composite material can be used in a humid or corrosive environment, has better electric corrosion resistance and has better mechanical properties at room temperature and high temperature.

Description

Technical Field

[0001] The present invention belongs to the field of materials, and in particular relates to a corrosion-resistant rare earth magnesium-based composite material and a preparation method and application thereof. Background Art

[0002] Rare earth magnesium alloys, with their advantages of low density, high strength, and excellent high-temperature stability, are widely used in fields such as petrochemicals, aerospace, and machinery manufacturing. However, the elongation of rare earth magnesium alloys generally rarely exceeds 5%, and their elastic modulus is comparable to that of conventional magnesium alloys, showing no significant improvement. To further expand the application of rare earth magnesium alloys, there is an urgent need to develop high-strength, high-toughness, and high-modulus rare earth magnesium alloy materials. Ti particles, with their high strength, elastic modulus, and excellent coordinated deformation ability, can be added as reinforcements to rare earth magnesium alloys to form composite materials, thereby simultaneously improving the strength, toughness, and modulus of rare earth magnesium alloys. However, due to the large potential difference between the standard electrode potential of Mg (-2.37V) and the standard electrode potential of Ti (-1.63V), Ti particle-reinforced rare earth magnesium-based composites experience severe galvanic corrosion at the Ti / Mg interface when used in humid or corrosive environments. Furthermore, the rare earth elements in the rare earth magnesium alloy tend to accumulate on the surface of the titanium particles, forming a rare earth-rich phase, which further reduces the corrosion resistance of the rare earth magnesium alloy, resulting in extremely poor corrosion resistance and severely limiting its application. Summary of the Invention

[0003] In order to overcome at least one of the technical problems existing in the above-mentioned prior art, one of the purposes of the present invention is to provide a rare earth magnesium-based composite material. The present invention introduces reinforcing particles into the magnesium substrate to form a good coherent or semi-coherent interface transition layer (for example, Mg 17 Al 12 , Ti3Al), and the aluminum element with a small potential difference with the magnesium substrate regulates the Ti / Mg interface, changes the interface structure of Ti and Mg, and reduces the electrochemical, especially galvanic corrosion rate, of rare earth magnesium-based composites while improving the interface bonding strength.

[0004] A second object of the present invention is to provide a method for preparing a rare earth magnesium-based composite material.

[0005] A third object of the present invention is to provide applications of the rare earth magnesium-based composite material in the fields of petrochemicals, aerospace, or machinery manufacturing.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The first aspect of the present invention provides a rare earth magnesium-based composite material, wherein the raw materials for preparing the rare earth magnesium-based composite material include a magnesium substrate and reinforced particles;

[0008] The reinforced particles include titanium particles and an aluminum coating layer coated on the surface of the titanium particles, and the mass ratio of the aluminum coating layer to the titanium particles is (5-10):100;

[0009] The magnesium substrate is a Mg-RE-Zn alloy; the RE is selected from at least one of Gd and Y;

[0010] In the magnesium substrate, the mass percentage of Gd is ≤11%, and / or the mass percentage of Y is ≤6%.

[0011] The standard electrode potential of aluminum is -1.67V. The potential difference between aluminum and magnesium is smaller than that between titanium and magnesium. A layer of aluminum with a thickness of nanometers on the surface of titanium particles acts as a barrier, blocking the direct contact between titanium and magnesium, converting the Ti / Mg interface into a Ti / Al / Mg interface, and reducing the potential difference between the interfaces. At the same time, Mg is generated at the Al / Mg interface. 17 Al 12 Phase, Mg 17 Al 12 The phase has strong corrosion resistance and can inhibit the local corrosion of Mg, thereby reducing the electrochemical reaction, especially the rate of galvanic corrosion. In addition, the wettability of the Al / Mg interface is better than that of the Ti / Mg interface, which can reduce the generation of microcracks on the interface, make the galvanic corrosion more uniform, and avoid the formation of severe local corrosion. When the composite material of the present invention is prepared, an in-situ reaction occurs on the surface of the titanium particles to generate a Ti3Al transition layer with a thickness of 150 to 300 nm. There is a coherent interface between Ti3Al and Ti, and the interface bonding strength is greater than the bonding strength between Ti and the Mg matrix. Due to the formation of a strong bonding interface transition layer, it is beneficial to the load transfer during the stress process of the material, thereby improving the strength and toughness of the material.

[0012] In some embodiments of the present invention, the mass ratio of the aluminum coating layer to the titanium particles is any one of 5:100, 5.5:100, 6:100, 6.5:100, 7:100, 7.5:100, 8:100, 8.5:100, 9:100, 9.5:100, and 10:100, or a range formed by any two of the above. If the mass ratio of the aluminum coating layer to the titanium particles is less than 5:100, the thickness of the aluminum coating layer is too thin. During the subsequent stirring and casting process to prepare the composite material, the Al element will diffuse into the melt, and the titanium particles are likely to have exposed surfaces. The exposed surfaces of the titanium particles are in direct contact with the magnesium matrix, causing local galvanic corrosion. If the mass ratio of the aluminum coating layer to the titanium particles is greater than 10:100, during the subsequent stirring and compounding, an excessively thick interface transition layer is generated at the Ti / Mg interface, and a large amount of complex intermetallic compounds are formed in the interface transition layer. The interface bonding strength is likely to decrease, resulting in reduced strength and toughness of the composite material.

[0013] In some embodiments of the present invention, the mass percentage of Gd in the magnesium substrate is 0.1-11%; in some embodiments of the present invention, the mass percentage of Gd in the magnesium substrate is any one of 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, or a range formed by any two of them.

[0014] In some embodiments of the present invention, the mass percentage of Y in the magnesium substrate is 0.1-6%; in some embodiments of the present invention, the mass percentage of Y in the magnesium substrate is any one of 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, or a range formed by any two of them.

[0015] In some embodiments of the present invention, the mass percentage of Zn in the magnesium substrate is 0.1-2%; in some embodiments of the present invention, the mass percentage of Zn in the magnesium substrate is 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, or any range formed by any two of them.

[0016] In some embodiments of the present invention, the mass percentage of Mg in the magnesium substrate is 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.7% or any range formed by any two of them.

[0017] In some embodiments of the present invention, the magnesium substrate includes the following components in mass percentage: Mg 81-99.7%, gadolinium (Gd) 0.1-11%, yttrium (Y) 0.1-6%, and Zn 0.1-2%.

[0018] In some embodiments of the present invention, the magnesium substrate is composed of the following components in mass percentage: Gd 0.1-11%, Y 0.1-6%, Zn 0.1-2%, and magnesium as the balance.

[0019] If uncoated titanium particles are introduced into the magnesium matrix, the RE elements in the magnesium matrix tend to be enriched near the titanium particles to form coarse rare earth-rich phase agglomerates, increasing the degree of electrochemical corrosion and reducing the electrical corrosion resistance of the composite material. When the titanium particles are coated with an aluminum coating, although the rare earth elements will accumulate on the surface of the reinforced particles, the presence of the interface transition layer will not reduce the electrical corrosion resistance of the composite material. However, when the Gd and Y contents exceed the above range, even if the surface of the reinforced particles is coated, the electrochemical corrosion in the area where the rare earth-rich phase agglomerates is still very serious.

[0020] In some embodiments of the present invention, the mass of the reinforcing particles is 1% to 20% of the mass of the magnesium substrate. In some embodiments of the present invention, the mass of the reinforcing particles is any one of 1%, 3%, 5%, 7%, 10%, 11%, 13%, 15%, 17%, and 20% of the mass of the magnesium substrate, or a range formed by any two of these values. If the amount of reinforcing particles added is less than 1%, the reinforcing effect on the rare earth magnesium alloy is insignificant. If the amount of reinforcing particles added is greater than 20%, the melt viscosity is excessively high, the fluidity is poor, casting is difficult, and a large number of metallurgical defects such as shrinkage cavities and porosity will form in the prepared composite material.

[0021] In some embodiments of the present invention, the titanium particles have a particle size of 5-15 μm. In some embodiments of the present invention, the titanium particles have a particle size of any one of 5 μm, 7 μm, 10 μm, 12 μm, 14 μm, and 15 μm, or a range formed by any two of these. If the average particle size of the titanium particles is less than 5 μm, the electro-explosion deposition process tends to coat the agglomerated particles together, making it difficult to achieve uniform coating of the particles. If the average particle size of the titanium particles is greater than 15 μm, their strengthening effect on the mechanical properties of the rare earth magnesium-based composite material is reduced.

[0022] In some embodiments of the present invention, the thickness of the aluminum coating layer is 350 to 550 nm; in some embodiments of the present invention, the thickness of the aluminum coating layer is any one of 350 nm, 370 nm, 400 nm, 420 nm, 440 nm, 460 nm, 480 nm, 500 nm, 520 nm, 540 nm, and 550 nm, or a range formed by any two of the values.

[0023] In some embodiments of the present invention, the rare earth magnesium-based composite material has a tensile strength measured at 25° C. of 375 to 395 MPa.

[0024] In some embodiments of the present invention, the yield strength of the rare earth magnesium-based composite material measured at 25° C. is 309-326 MPa.

[0025] In some embodiments of the present invention, the elongation of the rare earth magnesium-based composite material measured at 25° C. is 10.4-12.6%.

[0026] In some embodiments of the present invention, the rare earth magnesium-based composite material has a tensile strength measured at 200° C. of 248 to 276 MPa.

[0027] In some embodiments of the present invention, the yield strength of the rare earth magnesium-based composite material measured at 200° C. is 213-235 MPa.

[0028] In some embodiments of the present invention, the elongation of the rare earth magnesium-based composite material measured at 200° C. is 16.6-18.3%.

[0029] The second aspect of the present invention provides a method for preparing the rare earth magnesium-based composite material according to the first aspect of the present invention, comprising the following steps:

[0030] The reinforcing particles are mixed with a semi-solid rare earth magnesium alloy melt, and then cast and molded to obtain the rare earth magnesium-based composite material.

[0031] In some embodiments of the present invention, the reinforced particles are formed by forming an aluminum coating layer on the surface of titanium particles using a method of electric explosion deposition or spray deposition.

[0032] In some embodiments of the present invention, the mixing time is 3 to 5 minutes. In some embodiments of the present invention, the mixing time is any one of 3 minutes, 4 minutes, and 5 minutes, or a range formed by any two of the above. If the mixing time is too short, uniform particle distribution is difficult to achieve. If the mixing time is too long, the aluminum coating on the surface of the titanium particles will diffuse and migrate in large quantities, resulting in an excessively thin Ti / Mg interface transition layer, affecting its interfacial barrier function and reducing interfacial bonding strength.

[0033] In some embodiments of the present invention, the mixing rate is 400-500 rpm. In some embodiments of the present invention, the mixing rate is any one of 400 rpm, 410 rpm, 420 rpm, 430 rpm, 440 rpm, 450 rpm, 460 rpm, 470 rpm, 480 rpm, 490 rpm, and 500 rpm, or a range formed by any two of the above. If the mixing rate is too slow, the uniform dispersion effect is poor; if the mixing rate is too fast, the melt is easily thrown out.

[0034] In some embodiments of the present invention, the mixing is performed by stirring;

[0035] In some embodiments of the present invention, the mixing is performed under an inert atmosphere or a vacuum environment. In some embodiments of the present invention, the mixing is performed under a vacuum environment.

[0036] In some embodiments of the present invention, the vacuum degree during mixing is no greater than 1 Pa. If the vacuum degree is too low, oxidation will be severe during the stirring process, affecting the mechanical properties of the composite material.

[0037] In some embodiments of the present invention, the temperature of the rare earth magnesium alloy melt is T1, and the melting point of the rare earth magnesium alloy is T m , T m -20℃≤T1≤T m The present invention uses DSC to test the melting point of the rare earth magnesium alloy, i.e., the liquidus temperature. If the temperature of the rare earth magnesium alloy melt is too high, the reinforcement particles are likely to settle and macrosegregate. If the temperature of the rare earth magnesium alloy melt is too low, due to the high viscosity of the melt, the reinforcement particles are likely to agglomerate, making uniform dispersion difficult.

[0038] In some embodiments of the present invention, the casting temperature is T2, the melting point of the rare earth magnesium alloy is T m , T m +20℃≤T2≤T m +50℃.

[0039] The third aspect of the present invention provides the use of the rare earth magnesium-based composite material described in the first aspect of the present invention in the fields of petrochemical industry, aerospace or machinery manufacturing.

[0040] The beneficial effects of the present invention are as follows: the rare earth magnesium-based composite material of the present invention has a corrosion potential and corrosion current close to those of the magnesium substrate, thereby enabling it to be used in a humid or corrosive environment, having excellent electrical corrosion resistance, and having good mechanical properties at both room temperature and high temperature, specifically: the tensile strength at room temperature is 375-395 MPa, the yield strength is 309-326 MPa, and the elongation is 10.4-12.6%; the tensile strength at a high temperature of 200°C is 248-276 MPa, the yield strength is 213-235 MPa, and the elongation is 16.6-18.3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is the SEM image of the Al-Ti composite particles prepared in Example 1.

[0042] Figure 2 This is an EDS analysis diagram of the micro-area near the Ti particles of the magnesium-based composite material prepared in Example 1.

[0043] Figure 3 This is the EDS analysis diagram of the micro-area near the Ti particles of the magnesium-based composite material prepared in Comparative Example 2.

[0044] Figure 4 This is the micro-area potential distribution diagram of the magnesium-based composite material prepared in Example 1. DETAILED DESCRIPTION

[0045] The specific implementation of the present invention will be further described in detail below 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 if there are any processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. The reagents or instruments used that do not indicate the manufacturer are all conventional products that can be purchased commercially.

[0046] The raw material information used in the following examples and comparative examples is as follows:

[0047] Mg-9.2Gd-4.1Y-1.6Zn is composed of the following components in mass percentage: Gd 9.2%, Y 4.1%, Zn 1.6%, and Mg as the balance.

[0048] Mg-11.5Gd-4.1Y-1.6Zn is composed of the following components in mass percentage: Gd 11.5%, Y 4.1%, Zn 1.6%, and Mg as the balance.

[0049] Mg-9.2Gd-6.5Y-1.6Zn is composed of the following components in mass percentage: Gd 9.2%, Y 6.5%, Zn 1.6%, and Mg as the balance.

[0050] Mg-11.2Gd-6.3Y-1.6Zn is composed of the following components in mass percentage: Gd 11.2%, Y 6.3%, Zn 1.6%, and Mg as the balance.

[0051] Example 1

[0052] This example provides a method for preparing a corrosion-resistant rare earth magnesium-based composite material, and the specific steps are as follows:

[0053] (1) Using the electric explosion deposition method, a layer of aluminum was deposited on the surface of Ti particles with an average particle size of 10 μm. The mass ratio of the surface-coated Al to the mass of the Ti particles was 7.5:100. The specific method of electric explosion deposition is as follows: aluminum wire with a diameter of 0.4 mm and titanium particles were placed in an electric explosion chamber, and the electric explosion chamber was evacuated to 0.5×10 -2After the Pa, argon or other inert gas is filled in, and a pulse current is applied to the aluminum wire at a voltage of 12kV, an electrode spacing of 60mm, and a deposition distance of 30mm. Under the action of the high-density current, the aluminum wire instantly melts and vaporizes into metal vapor, which is dispersed onto the surface of the titanium particles. After cooling, a uniform aluminum coating layer with a certain thickness (i.e., the interface transition layer) is formed, resulting in Al-Ti composite particles with a core-shell structure.

[0054] The surface morphology of Al-Ti composite particles was tested by scanning electron microscopy. Figure 1 As shown. Figure 1 It can be seen that in this example, an aluminum-rich coating layer is formed on the surface of the Ti particles, and the size of the aluminum particles is ≤1 μm.

[0055] (2) The liquidus temperature of the Mg-9.2Gd-4.1Y-1.6Zn alloy was found to be 638°C by DSC detection.

[0056] (3) The Mg-9.2Gd-4.1Y-1.6Zn matrix alloy was placed in a crucible of a vacuum stirring furnace and melted at a vacuum degree of 5×10 -1 After the matrix alloy was completely melted, the melt temperature was lowered to 628°C. Al-Ti composite particles were then added to the semi-solid Mg-9.2Gd-4.1Y-1.6Zn melt and stirred. The mass of Al-Ti composite particles added was 10% of the mass of Mg-9.2Gd-4.1Y-1.6Zn. The stirring time was 4 minutes at a stirring speed of 450 rpm. After stirring, the semi-solid slurry was heated to 665°C and cast. The melt solidified in a metal mold to form the rare earth magnesium-based composite material in this example.

[0057] The EDS function of the scanning electron microscope was used to test the micro-region composition near the Ti particles in the rare earth magnesium-based composite material prepared in this example. The test results are as follows: Figure 2 As shown by Figure 2 It can be seen that an aluminum-rich layer is formed on the surface of the Ti particles in the rare earth magnesium-based composite material in this example, separating Ti and Mg, and the thickness of the aluminum-rich layer is about 425 nm.

[0058] Example 2

[0059] This example provides a method for preparing a corrosion-resistant rare earth magnesium-based composite material, which differs from the preparation method in Example 1 only in that the mass ratio of the surface-coated Al to the mass ratio of the Ti particles in step (1) is 5:100.

[0060] Example 3

[0061] This example provides a method for preparing a corrosion-resistant rare earth magnesium-based composite material, which differs from the preparation method in Example 1 only in that the mass ratio of the surface-coated Al to the mass ratio of the Ti particles in step (1) is 10:100.

[0062] Example 4

[0063] This example provides a method for preparing a corrosion-resistant rare earth magnesium-based composite material, which differs from the preparation method in Example 1 only in that: in step (3), stirring is performed under vacuum conditions for 3 minutes.

[0064] Example 5

[0065] This example provides a method for preparing a corrosion-resistant rare earth magnesium-based composite material, which differs from the preparation method in Example 1 only in that: in step (3), stirring is performed under vacuum conditions for 5 minutes.

[0066] Comparative Example 1

[0067] This example provides a method for preparing a rare earth magnesium-based composite material. The preparation steps are as follows: Mg-9.2Gd-4.1Y-1.6Zn matrix alloy is placed in a crucible of a vacuum stirring furnace and melted. The vacuum degree is 5×10 -1 When the matrix alloy is completely melted, the temperature is raised to 665°C for casting, and the melt solidifies and forms in a metal mold to obtain the rare earth magnesium-based composite material in this example.

[0068] The rare earth magnesium-based composite material in this example does not contain Al-Ti composite particles.

[0069] Comparative Example 2

[0070] This example provides a method for preparing a rare earth magnesium-based composite material, and the preparation steps are as follows:

[0071] The Mg-9.2Gd-4.1Y-1.6Zn matrix alloy was melted in a crucible of a vacuum stirring furnace with a vacuum degree of 5×10 - 1 After the matrix alloy was completely melted, the melt temperature was lowered to 628°C. Ti particles with an average particle size of 10 μm were then added to the semi-solid Mg-9.2Gd-4.1Y-1.6Zn melt and stirred. The mass of Ti particles added was 10% of the mass of Mg-9.2Gd-4.1Y-1.6Zn. The stirring time was 4 minutes at a stirring speed of 450 rpm. After stirring, the semi-solid slurry was heated to 665°C and cast. The melt solidified in a metal mold to form the rare earth magnesium-based composite material in this example.

[0072] The reinforcement phase in the rare earth magnesium-based composite material in this example is titanium particles, and the surface of the titanium particles is not coated with aluminum.

[0073] The EDS function of the scanning electron microscope was used to test the micro-region composition near the Ti particles in the rare earth magnesium-based composite material prepared in this example. Figure 3 As shown by Figure 3 It can be seen that no aluminum-rich layer is formed on the surface of the Ti particles in this example.

[0074] Comparative Example 3

[0075] This example provides a method for preparing a rare earth magnesium-based composite material, which differs from Example 1 only in that: in step (1), the mass ratio of the surface-coated Al to the mass ratio of the Ti particles is 2:100.

[0076] Comparative Example 4

[0077] This example provides a method for preparing a rare earth magnesium-based composite material, which differs from Example 1 only in that: in step (1), the mass ratio of the surface-coated Al to the mass ratio of the Ti particles is 15:100.

[0078] Comparative Example 5

[0079] This example provides a method for preparing a rare earth magnesium-based composite material, which differs from Example 1 only in that: in step (3), stirring is performed under vacuum conditions for 1 minute.

[0080] Comparative Example 6

[0081] This example provides a method for preparing a rare earth magnesium-based composite material, which differs from Example 1 only in that: in step (3), stirring is performed under vacuum conditions for 10 minutes.

[0082] Comparative Example 7

[0083] This example provides a method for preparing a rare earth magnesium-based composite material, which differs from Example 1 only in that an equal mass of Mg-11.5Gd-4.1Y-1.6Zn is used in step (3) of this example instead of Mg-9.2Gd-4.1Y-1.6Zn in Example 1.

[0084] Comparative Example 8

[0085] This example provides a method for preparing a rare earth magnesium-based composite material, which differs from Example 1 only in that an equal mass of Mg-9.2Gd-6.5Y-1.6Zn is used in step (3) of this example instead of Mg-9.2Gd-4.1Y-1.6Zn in Example 1.

[0086] Comparative Example 9

[0087] This example provides a method for preparing a rare earth magnesium-based composite material, which differs from Example 1 only in that an equal mass of Mg-11.2Gd-6.3Y-1.6Zn is used in step (3) of this example instead of Mg-9.2Gd-4.1Y-1.6Zn in Example 1.

[0088] Performance testing:

[0089] Samples were taken from the magnesium-based composite materials prepared in Examples 1 to 5 and Comparative Examples 1 to 9, and the thickness of the Ti / Mg interface transition layer, the room temperature mechanical properties (tensile strength, yield strength, elongation), high temperature mechanical properties (tensile strength, yield strength, elongation), and electrochemical corrosion (corrosion potential Ecorr and corrosion current density value Icorr) of the magnesium-based composite materials were tested. Among them, the micro-area potential distribution of the magnesium-based composite material in Example 1 was tested using an environmentally controlled high-resolution atomic force microscope (model: Cypher ES). The potential distribution diagram is shown in FIG. Figure 4 As shown. Figure 4 It can be seen that there is a potential transition zone between the potential zone corresponding to the titanium particles (dark area in the middle) and the potential zone corresponding to the magnesium matrix (light area on the periphery).

[0090] Among them, the test method for the thickness of the interface transition layer is: take a sample from the prepared magnesium-based composite material, grind and polish the sample, and then use a scanning electron microscope to perform EDS analysis to measure the thickness of the aluminum-rich layer on the surface of the Ti particles. This thickness is regarded as the thickness of the interface transition layer.

[0091] The test standard for the corrosion of magnesium-based composite materials refers to GB / T 24196-2009, and the corrosion potential (Ecorr) and corrosion current density value (Icorr) are measured.

[0092] The test standards for room temperature tensile strength, yield strength and elongation at break refer to GB / T16865-2013.

[0093] The test standards for high-temperature tensile strength, yield strength and elongation after fracture refer to GB / T228.2-2015, and the test temperature is 200°C.

[0094] The performance data of the magnesium-based composite materials prepared in Examples 1 to 5 and Comparative Examples 1 to 9 measured according to the above test method are shown in Table 1 below.

[0095] Table 1 Performance data of magnesium-based composite materials

[0096]

[0097]

[0098] As shown in Table 1, the rare earth magnesium-based composite materials prepared in Examples 1 to 5 of the present invention have an interface transition layer of appropriate thickness (thickness of 350 to 550 nm), which can enhance the interface strength between the titanium particles and the magnesium matrix on the one hand, and improve the corrosion resistance of the rare earth magnesium-based composite materials on the other hand. Specifically, the corrosion potential (Ecorr of the rare earth magnesium-based composite materials prepared in Examples 1 to 5 is -1.51 to -1.55 V SCE ) and corrosion current (Icorr is 2.42×10 -4 ~3.11×10 -4 μA·cm -2 ) are close to Mg-9.2Gd-4.1Y-1.6Zn, and have excellent corrosion resistance. In addition, the rare earth magnesium-based composite materials prepared in Examples 1 to 5 have excellent mechanical properties at room temperature and high temperature. Specifically, the tensile strength at room temperature is 375-395 MPa, the yield strength is 309-326 MPa, and the elongation is 10.4-12.6%; the tensile strength at a high temperature of 200°C is 248-276 MPa, the yield strength is 213-235 MPa, and the elongation is 16.6-18.3%.

[0099] While the embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above. Various modifications may be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof may be combined with one another unless there is a conflict.

Claims

1. A rare earth magnesium-based composite material, characterized in that: The raw materials for preparing the rare earth magnesium-based composite material include a magnesium substrate and reinforced particles; The reinforced particles include titanium particles and an aluminum coating layer coated on the surface of the titanium particles, and the mass ratio of the aluminum coating layer to the titanium particles is (5-10):100; The magnesium substrate is a Mg-RE-Zn alloy; the RE is selected from at least one of Gd and Y; In the magnesium substrate, the mass percentage of Gd is ≤11%, and / or the mass percentage of Y is ≤6%.

2. The rare earth magnesium-based composite material according to claim 1, characterized in that: The mass of the reinforcing particles is 1 to 20% of the mass of the magnesium substrate.

3. The rare earth magnesium-based composite material according to claim 1, characterized in that: The particle size of the titanium particles is 5-15 μm.

4. The rare earth magnesium-based composite material according to claim 1, characterized in that: The thickness of the aluminum coating layer is 350-550 nm.

5. The rare earth magnesium-based composite material according to claim 1, characterized in that: The magnesium substrate comprises the following components in mass percentage: Mg 81-99.7%, Gd 0.1-11%, Y 0.1-6%, and Zn 0.1-2%.

6. The method for preparing the rare earth magnesium-based composite material according to any one of claims 1 to 5, characterized in that: The following steps are involved: The reinforcing particles are mixed with a semi-solid rare earth magnesium alloy melt, and then cast and molded to obtain the rare earth magnesium-based composite material.

7. The method for preparing the rare earth magnesium-based composite material according to claim 6, wherein: The step of mixing has at least one of the following characteristics: (a1) The mixing time is 3 to 5 minutes; (a2) the mixing speed is 400-500 rpm; (a3) the mixing is carried out by stirring; (a4) The mixing is performed in an inert atmosphere or a vacuum environment.

8. The method for preparing the rare earth magnesium-based composite material according to claim 6, wherein: The temperature of the rare earth magnesium alloy melt is T1, and the melting point of the rare earth magnesium alloy is T m , T m -20℃≤T1≤T m .

9. The method for preparing the rare earth magnesium-based composite material according to claim 6, wherein: The casting temperature is T2, and the melting point of the rare earth magnesium alloy is T m , T m +20℃≤T2≤T m +50℃.

10. Use of the rare earth magnesium-based composite material according to any one of claims 1 to 5 in the fields of petrochemical industry, aerospace or machinery manufacturing.

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