Particle-reinforced aluminum-based composite material with sandwich structure and preparation method of particle-reinforced aluminum-based composite material

Abstract

The invention discloses a preparation method of a particle reinforced aluminum-based composite material with a sandwich structure, which comprises the following steps of: pretreating a pure aluminum plate and a high-entropy alloy particle reinforced aluminum-based prefabricated plate; then, the pure aluminum plates, the high-entropy alloy particle reinforced aluminum-based prefabricated plates and the pure aluminum plates are alternately stacked and fixed in a clamp of stirring friction machining equipment in the sequence of the pure aluminum plates, the high-entropy alloy particle reinforced aluminum-based prefabricated plates and the pure aluminum plates; the high-entropy alloy particle reinforced aluminum-based prefabricated slab is formed by taking aluminum as a base body, obtaining a high-entropy alloy particle reinforced aluminum-based composite material sintered ingot by adopting a powder metallurgy process and then slicing the high-entropy alloy particle reinforced aluminum-based composite material sintered ingot; and the three stacked plates are subjected to single-pass processing preparation through a stirring friction processing technology, and the particle reinforced aluminum matrix composite with the sandwich structure is obtained. The particle-reinforced aluminum-based composite material is combined with a laminated structure, the novel particle-reinforced aluminum-based composite material with a sandwich structure is constructed by utilizing a stirring friction processing technology, and the mechanical property of the prepared material is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy processing and preparation technology, specifically relating to a sandwich-structured particle-reinforced aluminum matrix composite material and its preparation method. Background Technology

[0002] Aluminum and its alloys have wide applications due to their low density, high specific strength, excellent thermal and electrical conductivity, and processing properties. To further enhance their energy limits, particle-reinforced metal composites have emerged. By introducing high-modulus, high-hardness particles (such as SiC, Al2O3, and HEA) as reinforcing phases, the strength and wear resistance of aluminum alloys have been significantly improved. However, traditional particle-reinforced aluminum matrix composites have inherent performance bottlenecks, namely the so-called "strength-toughness inversion" relationship. In addition, uneven particle distribution and difficulty in controlling interfacial reactions can easily become stress concentration points, leading to early failure and impairing the fatigue performance and damage tolerance of the material. This greatly limits their widespread application in critical load-bearing structures.

[0003] Another type of biomimetic metal laminated composite material achieves excellent fracture toughness on a macroscopic scale by alternating and firmly bonding layers with different properties. This is achieved through interface and structural design to control crack propagation paths, deflection, and energy absorption, resulting in a combination of properties that is difficult to achieve with a single homogeneous material. Currently, researchers mostly use hot-pressing sintering and rolling composite methods to obtain sandwich-structured multilayer composite plates. However, due to the high temperatures during the preparation process, excessive metallurgical reactions often occur at the interface between the particle reinforcement and the aluminum matrix. Strict control of the preparation process parameters is necessary; otherwise, the mechanical properties of the composite material may decline. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a sandwich-structured particle-reinforced aluminum matrix composite material and its preparation method.

[0005] Technical solution: The present invention provides a method for preparing a sandwich-structured particle-reinforced aluminum matrix composite material, comprising the following steps: (1) The pure aluminum plate and the high-entropy alloy particle reinforced aluminum matrix prefabricated plate are pretreated, and then stacked alternately in the order of pure aluminum plate-high-entropy alloy particle reinforced aluminum matrix prefabricated plate-pure aluminum plate and fixed in the fixture of the friction stir processing equipment; the high-entropy alloy particle reinforced aluminum matrix prefabricated plate is made by sintering an aluminum matrix composite material with high-entropy alloy particle reinforced by powder metallurgy and then slicing it. (2) Install the stirring tool head at the head of the friction stirring processing equipment, set the processing parameters, and use the friction stirring processing technology to process the three stacked plates in a single pass to obtain a particle-reinforced aluminum matrix composite material with a sandwich structure.

[0006] Furthermore, the pretreatment steps include: cutting the pure aluminum plate and the high-entropy alloy particle-reinforced aluminum-based prefabricated plate into uniform sizes, then polishing the upper and lower surfaces of the plate with metallographic sandpaper to remove the oxide layer, then ultrasonically cleaning at 25~40 ℃ for 15~25 min, and finally cleaning the surface of the plate with anhydrous ethanol and drying it.

[0007] Furthermore, the thickness of the pure aluminum plate and the high-entropy alloy particle-reinforced aluminum-based prefabricated plate is 2~3 mm.

[0008] Furthermore, the stirring tool head is made of H13 tool steel, with a shoulder diameter of 22 mm and a stirring needle length of 3.5 mm.

[0009] Furthermore, the parameters of the friction stir machining process are as follows: the rotation speed of the stirring tool is 850~1100 r / min, the travel speed is 30~60 mm / min, the downward pressure is 0.1~0.3 mm, and the tilt angle is 0°.

[0010] Another object of the present invention is to provide a sandwich-structured particle-reinforced aluminum matrix composite material prepared according to the above-described preparation method.

[0011] Furthermore, the sandwich-structured particle-reinforced aluminum matrix composite material has a tensile strength of 110~130 MPa parallel to the processing direction and a failure strain of 25.5%~32.5%.

[0012] Compared with the prior art, the present invention has the following significant advantages: (1) The present invention combines particle-reinforced aluminum matrix composite material with a laminated structure and uses a stir friction processing technology to construct a novel particle-reinforced aluminum matrix composite material with a sandwich structure. Through the frictional heat and stirring action generated by the stirring tool on the plate, the material undergoes plastic deformation and flow, realizing a tight bond between the pure aluminum plate and the high-entropy alloy particle-reinforced aluminum matrix precast plate. By alternately stacking and firmly bonding layers with different properties, the crack propagation path, deflection and energy absorption are controlled through interface and structural design, thereby achieving excellent fracture toughness on a macroscopic scale, realizing a performance combination that is difficult to achieve with a single homogeneous material. The preparation process is efficient, environmentally friendly and has high forming quality.

[0013] (2) The sandwich-structured particle-reinforced aluminum matrix composite material prepared by this invention undergoes plastic deformation and flow due to the frictional heat and stirring action generated by the stirring tool of the friction stir processing equipment. The plastic rheology of the material can effectively close the pore defects inside the raw material. At the same time, since the processing temperature is low, it can be carried out at room temperature, which is less likely to cause excessive metallurgical reaction at the interface. This optimizes the interfacial bonding state between the particles and the aluminum matrix, which is beneficial to improving the mechanical properties of the aluminum matrix composite material. Meanwhile, under the thermo-mechanical coupling effect generated by the stirring tool, the grains of the metal matrix break and twist, and then undergo recovery and recrystallization, eventually forming fine equiaxed crystals. The mechanical properties of the composite material are improved through the synergistic effect of fine grain strengthening, dispersion strengthening and layered structure toughening mechanism.

[0014] (3) The particle-reinforced aluminum matrix composite material obtained by the present invention has been tested many times. Its tensile strength parallel to the processing direction is 110~130 MPa and its failure strain is 25.5%~32.5%, and its mechanical properties have been significantly improved. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the forming process of the preparation method of the present invention.

[0016] Figure 2 The flowchart illustrates the preparation process of the sandwich-structured particle-reinforced aluminum matrix composite material in this embodiment.

[0017] Figure 3 This is a SEM scan image (×30) of the cross-section of the processing area in Example 1.

[0018] Figure 4 (a) HEA in Example 1 p / SEM scan image of the original state of the Al precast slab; Figure 4 (b) is a composite material HEA p / Al intermediate layer SEM scan image.

[0019] Figure 5 This is a SEM scan image (×30) of the cross-section of the processing area in Example 2.

[0020] Figure 6 The image shows the electron backscattering diffraction (IPF) pattern of the aluminum substrate in Example 2. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] The present invention discloses a method for preparing a sandwich-structured particle-reinforced aluminum matrix composite material, the forming process of which is shown in the attached figure. Figure 1 As shown, it includes the following steps: (1) The pure aluminum plate 1 and the high-entropy alloy particle reinforced aluminum matrix prefabricated plate 2 are pretreated, and then stacked alternately in the order of pure aluminum plate 1-high-entropy alloy particle reinforced aluminum matrix prefabricated plate 2-pure aluminum plate 1 and fixed in the fixture of the friction stir processing equipment; the high-entropy alloy particle reinforced aluminum matrix prefabricated plate 2 is made by sintering an aluminum matrix composite material with high-entropy alloy particle reinforcement obtained by powder metallurgy and then slicing it. In a specific implementation, the pretreatment process includes: (11) Cutting of raw materials: Using an electric discharge wire cutter, slices are made along the direction perpendicular to the axial direction of the cylindrical high-entropy alloy particle reinforced metal matrix composite sintering ingot to obtain several high-entropy alloy particle reinforced aluminum matrix precast plates 2 with similar thicknesses; pure aluminum plate 1 is cut to ensure that it has the same size as the high-entropy alloy particle reinforced aluminum matrix precast plate. The thickness of pure aluminum plate 1 and high-entropy alloy particle reinforced aluminum matrix precast plate 2 is 2~3 mm. (12) Pretreatment of plates: Metallographic sandpaper is used to grind the upper and lower surfaces of the cut pure aluminum plate 1 and high-entropy alloy particle reinforced aluminum matrix precast plate 2 to remove the oxide layer, and then the polished plates are cleaned by an ultrasonic cleaner for 15~25 min at a temperature of 25~40℃ to further remove residual impurities on the surface, and finally the surface of the plates is cleaned with anhydrous ethanol and dried.

[0023] (2) The stirring tool head 3 is installed at the head of the friction stir processing equipment. The processing parameters are set, and the three stacked plates are processed in a single pass using the friction stir processing technology to obtain a particle-reinforced aluminum matrix composite material with a sandwich structure. In a specific embodiment, the stirring tool head 3 is made of H13 tool steel, the shoulder diameter is 22 mm, and the length of the stirring pin is 3.5 mm. The parameters of the friction stir processing technology are as follows: the stirring tool rotation speed is 850~1100 r / min, the travel speed is 30~60 mm / min, the downward pressure is 0.1~0.3 mm, and the tilt angle is 0°.

[0024] The following detailed description uses specific examples. Taking an aluminum substrate as an example, its preparation flowchart is attached. Figure 2 As shown in Table 1, the specific chemical composition of the raw materials used in this method is as follows.

[0025] Table 1: Chemical Composition of Metal (Alloy) Raw Materials

[0026] Example 1 (1) Raw material cutting and processing: High entropy alloy particles reinforced aluminum matrix composite material (HEA) with a diameter of about 70 mm were obtained through powder metallurgy process. p / Al) cylindrical sintered ingots were sliced ​​using an electrical discharge wire cutting machine along a direction perpendicular to the sintered ingot axis to obtain several HEAp / Al prefabricated plates with a thickness of approximately 2 mm; 1100 commercial pure aluminum plates of the same thickness were cut into HEAp / Al prefabricated plates. p / Al prefabricated panels are round materials with the same dimensions; (2) Pretreatment of sheet metal: Metallographic sandpaper was used to pretreat the cut 1100 pure aluminum sheet and HEA. p The upper and lower surfaces of the Al precast panels are polished to remove the oxide layer and contaminants. Then, the polished panels are cleaned with an ultrasonic cleaner for 20 minutes at a temperature of 30°C to further remove surface oxide particles and impurities. Finally, the surface of the panels is cleaned with anhydrous ethanol and dried for later use. (3) Friction stir processing preparation steps: Take two pretreated 1100 pure aluminum plates and one HEA plate p / Al precast slab, in accordance with "1100Al-HEA" p The " / Al -1100Al" materials are stacked alternately and fixed at the center of the processing platform of the friction stir machining (FSM) equipment. A stirring tool head, made of H13 tool steel with a shoulder diameter of 22 mm and a 3.5 mm long frustum-shaped stirring pin with a left-hand thread, is installed at the head of the FSM equipment. The starting point coordinates and processing parameters are set. The specific process parameters are as follows: rotational speed 880 r / min, travel speed 36 mm / min, downward pressure 0.25 mm, and tilt angle 0°. The stacked raw materials are processed in a single pass using the FSM process at room temperature to obtain a particle-reinforced aluminum matrix composite material with a sandwich structure.

[0027] The cross-sectional sample of the processed area obtained in this embodiment was subjected to microscopic observation after grinding and polishing. Its overall morphology is shown in the attached figure. Figure 3 As shown, the mixing zone has a sandwich structure, with the top and bottom layers being Al layers and the middle layer being HEA. p The Al layer showed tight interlayer bonding, with no obvious defects observed. The intermediate layer was magnified and compared with HEA. p The original microstructure of the Al precast slab was compared and observed, as shown in the attached figure. Figure 4 As shown. HEA p / Al precast panels have a loose internal structure and low density. HEA p The Al interface exhibits weak bonding defects, while the intermediate layer of the stirred zone has a dense structure with dispersed particle distribution and HEA. p The bonding state of the / Al interface is significantly improved, and no obvious interface reaction layer is formed.

[0028] The mechanical properties of the composite material obtained in this embodiment are as follows: strain rate is 0.001 / s, tensile strength parallel to the processing direction is 110 MPa, and failure strain is 32.5%. Compared with 1100 pure aluminum plate, its mechanical properties are significantly improved.

[0029] Example 2

[0030] The cutting and pretreatment of raw materials and the pretreatment of boards are the same as in Example 1.

[0031] Friction stir processing preparation steps: Two 1100 pure aluminum plates and one HEA sheet are then mixed. p / Al precast panels are manufactured according to "1100Al-HEA" p The three stacked sheets, labeled "Al-1100Al", were alternately stacked and fixed at the center of the processing platform of a friction stir machining (FSM) machine. A stirring tool head, made of H13 tool steel with a shoulder diameter of 22 mm and a 3.5 mm long frustum-shaped stirring pin with a left-hand thread, was installed at the head of the FSM machine. The starting point coordinates and processing parameters were set. Specific parameters were: rotational speed 1000 r / min, travel speed 60 mm / min, downward pressure 0.25 mm, and tilt angle 0°. The three stacked sheets were processed in a single pass using FSM at room temperature to obtain a particle-reinforced aluminum matrix composite material with a sandwich structure.

[0032] After grinding and polishing, the cross-sectional sample of the processing area obtained in this embodiment was subjected to microscopic observation of the overall morphology of its stirring zone, such as... Figure 5 As shown, the structural features are similar to those in Example 1. Furthermore, the Al grain characteristics were characterized using electron backscattering diffraction (ESD) and the grain size was statistically analyzed, as shown below. Figure 6 As shown, the Al grains are equiaxed with a grain size of 4.9 ± 2.8 μm. During the friction stir process, the aluminum grains underwent dynamic recrystallization, forming fine equiaxed grains.

[0033] The mechanical properties of the composite material obtained in this embodiment are as follows: strain rate is 0.001 / s, tensile strength parallel to the processing direction is 125 MPa, and failure strain is 21.7%. Compared with 1100 pure aluminum plate, its mechanical properties are significantly improved.

[0034] As can be seen from Examples 1-2, the sandwich-structured particle-reinforced aluminum matrix composite material manufactured using the preparation method of the present invention has the characteristics of low density, high strength, and good plasticity. This composite material consists of alternating Al layers and HEA... p Composed of Al layers and Al layers, the tissue has high density, HEA p The Al interface exhibits good bonding with no obvious metallurgical reaction layer, and the Al grains are equiaxed and small in size. Figure 4 , Figure 6 As shown, the obtained sandwich-structured particle-reinforced aluminum matrix composite material can fully utilize the synergistic effects of fine-grain strengthening, dispersion strengthening, and the toughening mechanism of the laminated structure to improve the strength and toughness of the material. The preparation process is completed at room temperature using a stir friction processing device, which is simple, efficient, short, and pollution-free.

Claims

1. A method for producing a sandwich-structured particulate-reinforced aluminum matrix composite material, characterized by, The preparation method comprises the following steps: (1) pretreating pure aluminum plates and high-entropy alloy particle reinforced aluminum matrix preformed plates, then alternately stacking and fixing the plates in the order of pure aluminum plate-high-entropy alloy particle reinforced aluminum matrix preformed plate-pure aluminum plate in a clamp of a friction stir processing device; the high-entropy alloy particle reinforced aluminum matrix preformed plate is obtained by slicing a sintered ingot of an aluminum matrix high-entropy alloy particle reinforced aluminum matrix composite material prepared by a powder metallurgy process; (2) installing a stirring tool head at a machine head of the friction stir processing device, setting processing parameters, and using a friction stir processing process to process the stacked three plates in a single pass to obtain a sandwich structure particle reinforced aluminum matrix composite material.

2. The method of producing a sandwich-structured particulate-reinforced aluminum matrix composite material according to claim 1, characterized by, The pretreatment step comprises the following steps: cutting the pure aluminum plates and high-entropy alloy particle reinforced aluminum matrix preformed plates into plates of the same size, then polishing the upper and lower surfaces of the plates using a metallographic sandpaper to remove the oxide layer, then ultrasonic cleaning the plates at 25-40 ℃ for 15-25 min, and finally cleaning the surfaces of the plates with anhydrous ethanol and drying.

3. The method of producing a sandwich-structured particulate-reinforced aluminum matrix composite material according to claim 1, characterized by, The thickness of the pure aluminum plates and high-entropy alloy particle reinforced aluminum matrix preformed plates is 2-3 mm.

4. The method of producing a sandwich-structured particulate-reinforced aluminum matrix composite material according to claim 1, characterized by, The material of the stirring tool head is H13 tool steel, the shoulder diameter is 22 mm, and the length of the stirring needle is 3.5 mm.

5. The method of producing a sandwich-structured particulate-reinforced aluminum matrix composite material according to claim 1, characterized by, The friction stir processing parameters are as follows: the stirring tool rotation speed is 850-1100 r / min, the travel speed is 30-60 mm / min, the pressing amount is 0.1-0.3 mm, and the inclination angle is 0°.

6. A sandwich-structured particulate-reinforced aluminum matrix composite material, characterized by, The sandwich structure particle reinforced aluminum matrix composite material is prepared by the preparation method according to any one of claims 1-4.

7. The sandwich-structured particulate reinforced aluminum matrix composite material of claim 6, wherein, The sandwich structure particle reinforced aluminum matrix composite material has a tensile strength of 110-130 MPa and a failure strain of 25.5%-32.5% in the direction parallel to the processing direction.

Images