CN-121972913-A - Magnesium alloy plate with gradient twin crystal structure and preparation method and application thereof

Abstract

A preparation method of a magnesium alloy plate with a gradient twin crystal structure belongs to the technical field of heterostructure material preparation. The method comprises the steps of firstly taking a magnesium alloy plate as a substrate, carrying out double-heat-source auxiliary heating friction stir solid-phase additive manufacturing by adopting the same-grade magnesium alloy wires, obtaining a deposited plate with preferred orientation of crystal grains in the thickness direction by regulating and controlling heating temperature and process parameters of a deposition head, then keeping the substrate in a heating state, carrying out heat-source auxiliary ultrasonic rolling on the deposited plate, enabling the crystal grains in the thickness direction of the plate to generate different degrees of twin deformation by regulating and controlling rolling parameters, and finally separating the substrate from the deposited plate to obtain the magnesium alloy plate with the gradient twin crystal structure. The method does not introduce heterogeneous particles, has the advantages of pure material, short process flow, high production efficiency and low cost, and the prepared plate has fine crystal grains, a gradient twin structure penetrates through the thickness and excellent comprehensive performance, is suitable for industrial production, and can be applied to the fields of automobiles, aerospace, medical appliances and the like.

Inventors

• HAN PENG
• Qiang Fengming
• CAO ZIXUAN
• GAO FENG
• QIAO KE
• WANG WEN
• WANG KUAISHE
• MA QIANZHI
• CAI JUN
• LIN JIA

Assignees

• 西安建筑科技大学

Dates

Publication Date

20260505

Application Date

20260116

Claims (10)

1. 1. The preparation method of the magnesium alloy plate with the gradient twin crystal structure is characterized by comprising the following steps of: s1, selecting a magnesium alloy plate as a metal substrate, and fixing the magnesium alloy plate on a workbench of friction stir additive manufacturing equipment; Respectively heating a magnesium alloy wire and a magnesium alloy plate, and carrying out friction stir solid phase additive manufacturing to obtain a heated magnesium alloy deposited plate with different preferred orientations of crystal grains along the thickness direction; s2, keeping the heating temperature of the magnesium alloy substrate unchanged, and carrying out ultrasonic rolling on the magnesium alloy deposited plate to enable crystal grains with different orientations to generate twin deformation along the thickness direction of the plate, so as to obtain the magnesium alloy deposited plate after ultrasonic rolling; S3, separating the magnesium alloy deposited plate subjected to ultrasonic rolling from the metal substrate to obtain the magnesium alloy plate with the gradient twin crystal structure.
2. 2. The method for producing a magnesium alloy sheet material having a gradient twin structure as defined in claim 1, wherein the magnesium alloy sheet material and the magnesium alloy wire material in S1 are of the AZ series or ZK series.
3. 3. The preparation method of the magnesium alloy plate with the gradient twin crystal structure as set forth in claim 1, wherein the thickness of the magnesium alloy substrate in S1 is less than or equal to 5mm, and the diameter of the magnesium alloy wire is 2-3 mm.
4. 4. The method for preparing a magnesium alloy sheet with a gradient twin structure according to claim 1, wherein in S1, a resistance wire double heat source is specifically adopted to heat the magnesium alloy wire and the magnesium alloy sheet respectively; heating temperature of the magnesium alloy wire In units of °c, where The empirical coefficient is 0.8-0.9, The melting point of the magnesium alloy wire; The heating temperature of the upper surface of the magnesium alloy plate In units of °c, where The empirical coefficient is 0.6-0.8.
5. 5. The method for preparing the magnesium alloy plate with the gradient twin crystal structure according to claim 4, wherein the downward pressing load of the deposition head in the friction stir solid phase additive manufacturing in S1 is 3-6 KN, the rotation speed of the deposition head is 1000-3800 r/min, and the advancing speed of the deposition head is 50-300 mm/min.
6. 6. The method for preparing a magnesium alloy plate with a gradient twin crystal structure according to claim 5, wherein the thickness of the single-layer magnesium alloy plate is realized by adjusting the distance between the shaft shoulder of the deposition head and the upper surface of the metal substrate, and the thickness of the deposition layer is thick Wherein L is the distance between the shaft shoulder of the deposition head and the upper surface of the magnesium alloy plate, and the value is 1-3, and the unit is mm.
7. 7. The method for preparing a magnesium alloy sheet with a gradient twin structure according to any one of claims 1 to 6, wherein the ultrasonic rolling pressure in S2 is 300 to 800n, the amplitude is 5 to 9 μm, and the speed is 50 to 80mm/min.
8. 8. The method for manufacturing a magnesium alloy sheet with a gradient twin crystal structure according to claim 7, wherein the magnesium alloy deposited sheet is ultrasonically rolled in a "serpentine" trajectory by ultrasonic rolling.
9. 9. The magnesium alloy sheet with the gradient twin crystal structure is characterized by being prepared by the preparation method of the magnesium alloy sheet with the gradient twin crystal structure according to any one of claims 1-8.
10. 10. An application of the magnesium alloy sheet with the gradient twin structure prepared by the preparation method of the magnesium alloy sheet with the gradient twin structure of any one of claims 1-8.

Description

Magnesium alloy plate with gradient twin crystal structure and preparation method and application thereof Technical Field The invention belongs to the technical field of heterostructure materials, and relates to a magnesium alloy plate with a gradient twin crystal structure, and a preparation method and application thereof. Background Heterostructure metals refer to metallic materials having two or more microstructures with differences in properties. Different structures in the heterostructure metal can obviously improve the comprehensive mechanical property and the service property of the heterostructure metal through mutual coordination. The types of heterostructures include gradient heterostructures, multiphase heterostructures, lamellar heterostructures, defect heterostructures, enhanced-phase heterostructures, multilevel heterostructures, etc., wherein gradient heterostructures (also called gradient structures) are one of the typical types, the core feature of which is that the internal microstructure of the material exhibits gradient distribution, such as grain size gradient distribution, phase volume fraction gradient distribution, twin gradient distribution, etc. The magnesium alloy has the advantages of low density, high specific strength, good recoverability and the like, is widely applied to the fields of automobiles, aerospace, medical appliances and the like, and is known as a green engineering material in the 21 st century. Along with the continuous improvement of the requirements of high-performance materials, the preparation requirements of the gradient structure magnesium alloy are increasingly urgent. The preparation methods of the existing gradient structure materials are mainly divided into two types, namely a heterogeneous particle induced gradient structure and a special deformation induced gradient structure. The heterogeneous particles induced by the gradient structure have inherent defects that the original components of the material are changed to obviously reduce the purity of the material, and the heterogeneous particles and the metal matrix are easy to generate stress concentration in the subsequent service process, so that the plasticity and toughness of the material are greatly reduced. The special deformation-induced gradient structure has the problems of long process flow, low production efficiency and high cost, and the prepared gradient material has larger scale and macroscopically presents a gradient structure, but has uniform tissue under microscopic scale, and cannot meet the application requirements of the gradient magnesium alloy sheet. Disclosure of Invention Aiming at the defects and shortcomings in the prior art, the invention aims to provide the magnesium alloy sheet with the gradient twin crystal structure, and the preparation method and the application thereof, so that the high-quality, high-efficiency and low-cost preparation of the magnesium alloy sheet with the gradient twin crystal structure is realized, the purity of the material components is ensured, and the application requirements of the related fields on the magnesium alloy sheet with the gradient twin crystal structure are met. In order to achieve the technical effects, the invention adopts the following technical scheme: The preparation method of the magnesium alloy plate with the gradient twin crystal structure comprises the following steps: s1, selecting a magnesium alloy plate as a metal substrate, and fixing the metal substrate on a workbench of friction stir material increase manufacturing equipment, selecting a magnesium alloy wire with the same brand as the metal substrate as an material increase raw material, respectively heating the magnesium alloy wire and the magnesium alloy plate, and performing friction stir solid phase material increase manufacturing to obtain a heated magnesium alloy deposited plate with different preferential orientations of crystal grains in the thickness direction; s2, keeping the heating temperature of the magnesium alloy substrate unchanged, and carrying out ultrasonic rolling on the magnesium alloy deposited plate to enable crystal grains with different orientations to generate twin deformation along the thickness direction of the plate, so as to obtain the magnesium alloy deposited plate after ultrasonic rolling; S3, separating the magnesium alloy deposited plate subjected to ultrasonic rolling from the metal substrate to obtain the magnesium alloy plate with the gradient twin crystal structure. 2. The method for preparing the magnesium alloy sheet material with the gradient twin crystal structure according to claim 1, wherein the marks of the magnesium alloy sheet material and the magnesium alloy wire material in the S1 are AZ series or ZK series. Preferably, the thickness of the magnesium alloy substrate in the step S1 is less than or equal to 5mm, and the diameter of the magnesium alloy wire is 2-3 mm. Preferably, in S1, the resistance wire double heat source