High-modulus high-strength aluminum matrix composite material and preparation method thereof

Abstract

The application relates to the technical field of metal matrix composites, in particular to a high-modulus and high-strength aluminum matrix composite material and a preparation method thereof. The high-modulus and high-strength aluminum matrix composite material comprises aluminum alloy matrix powder and reinforcing phase particles; the aluminum alloy matrix powder comprises Mg, Si, Mn, Sc, Zr, the balance of Al and inevitable impurities; the reinforcing phase particles comprise TiN and Si3N4 nanoparticles; the preparation method comprises the following steps: uniformly mixing the aluminum alloy matrix powder and the reinforcing phase particles by adopting a ball milling process to obtain aluminum matrix composite powder mixture; then performing a forming experiment on the mixture by adopting a selective laser melting process to obtain a sample material; and finally directly aging heat treating the sample material to obtain the aluminum matrix composite material. The high-modulus and high-strength aluminum matrix composite material not only has excellent forming performance, but also has excellent mechanical performance, and can meet the demand for high-performance materials in the fields of aerospace, automobiles and ships.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal matrix composites, in particular to a high-modulus and high-strength aluminum matrix composite material formed by selective laser melting and subsequent heat treatment process synergistic regulation of nanoscale dual ceramic particle hybrid reinforcement and a preparation method thereof. BACKGROUND

[0002] Currently, the research on selective laser melting aluminum matrix composites mainly focuses on the following aspects: (1) Single reinforcing phase aluminum matrix composite system: mainly using SiC, Al2O3 or TiB2 as a single ceramic particle as a reinforcing phase, prepared by ball milling process combined with selective laser melting (SLM) process. For example, SiC reinforced aluminum matrix composite. (2) Micro-alloying modification research: by adding Sc, Zr and other micro-alloying elements in the aluminum matrix, the strengthening effect is realized by using the formed nanoscale precipitates. For example, the Sc element modified Al-Mg alloy system is one of the current research focuses. (3) Post-processing process optimization: for SLM formed aluminum alloy materials, researchers often use traditional T6 heat treatment system, namely solid solution + aging treatment process for performance regulation.

[0003] However, the existing technology has the following problems: (1) Reinforcing phase distribution uniformity problem: when adding a single type of nanoparticles and the content exceeds a certain threshold, particle agglomeration phenomenon is easy to occur in the mechanical ball milling and SLM processing process; such agglomeration will lead to uneven composition distribution in the molten pool, and thus cause the material density to decrease, ultimately affecting the mechanical properties of the material. (2) Limitation of mechanical property improvement: micro-alloying: adding Sc and other rare earth elements can significantly improve the material performance, but the high cost limits its industrial application; reinforcing phase: single reinforcing phase composite material can improve the strength of the matrix, but the improvement is limited. (3) Heat treatment process adaptability problem: the traditional T6 treatment process (typical parameters are 500℃ solid solution treatment + aging treatment) is easy to cause the coarsening of the nanoscale reinforcing phase, and thus cause the material strength to decrease. Therefore, it is urgent to design a new technical solution to solve the problems in the background art. SUMMARY

[0004] The purpose of the present application is to provide a high-modulus and high-strength aluminum matrix composite material and a preparation method thereof, which can effectively solve the problems in the prior art.

[0005] To solve the above technical problems, the following technical solutions are adopted in the present application:

[0006] A high-modulus and high-strength aluminum matrix composite material, comprising an aluminum alloy matrix powder and reinforcing phase particles.

[0007] The aluminum alloy matrix powder comprises, in percentage by mass: Mg: 7-9 wt.%, Si: 0.4-2.5 wt.%, Mn: 0.3-0.8 wt.%, Sc: 0.5-0.7 wt.%, Zr: 0.2-0.5 wt.%, and the balance of Al and inevitable impurities;

[0008] The reinforcing phase particles comprise TiN and Si3N4 nanoparticles, wherein the TiN is added in an amount of 1 wt.% of the mass of the aluminum-based composite powder mixture (the mixture of the aluminum alloy matrix powder and the reinforcing phase particles); and the Si3N4 is added in an amount of 1 wt.% of the mass of the aluminum-based composite powder mixture (the mixture of the aluminum alloy matrix powder and the reinforcing phase particles).

[0009] Further, the particle size distribution of the aluminum alloy matrix powder is 15-53 μm; and the average particle size of the TiN and Si3N4 nanoparticles in the reinforcing phase particles is 80 nm.

[0010] Meanwhile, the application also relates to a preparation method of the high-modulus high-strength aluminum-based composite material, which comprises the following steps: uniformly mixing the aluminum alloy matrix powder and the reinforcing phase particles by adopting a ball milling process to obtain an aluminum-based composite powder mixture; then performing a forming experiment on the mixture by adopting a selective laser melting process to obtain a sample material; and finally directly subjecting the sample material to aging heat treatment to obtain the aluminum-based composite material.

[0011] Further, the parameters of the ball milling process are as follows: the ball-to-material ratio is 7:1; the ball milling speed is 200 r / min; the ball milling time is 2-3 h (30 min of operation + 5 min of pause); and high-purity argon is filled in the ball milling tank during the ball milling process, and the ball milling tank is sealed to ensure that the oxygen content is less than 100 ppm, so as to avoid oxidation and ensure uniform dispersion of the nanoparticles.

[0012] Further, the steps of the selective laser melting process comprise:

[0013] (1) a three-dimensional model of a target sample is constructed, and then a slicing software is used for layering processing, and the single-layer powder spreading thickness is set to be 40 μm;

[0014] (2) an AlSi10Mg substrate with a thickness of 20 mm is selected, and after sandblasting treatment, the surface roughness Ra is controlled to be 3.2-6.4 μm, so as to ensure uniform spreading of the first layer of powder;

[0015] (3) the laser additive manufacturing process is performed under an argon protective atmosphere, and the process parameters are as follows: the laser power is 350 W; the scanning speed is 1000 mm / s; the scanning interval is 100 μm; the powder layer thickness is 40 μm; and the scanning strategy is a zonal strip scanning with a layer-to-layer corner angle of 67°.

[0016] The above process parameters have a great influence on the forming quality of aluminum matrix composites, and then affect its mechanical properties. Changing the laser power, scanning speed and scanning interval will affect the relative density and defect condition of aluminum matrix composites laser melting forming. Based on the previous experimental research of the research group, the scanning interval, powder layer thickness, scanning strategy and layer angle are fixed, and the laser power (250 W-450 W) and scanning speed (900-2500 mm / s) are changed. In the previous process parameter optimization, it is found that with the increase of laser power, the forming quality of the composite material first increases and then decreases; with the increase of scanning speed, the quality of the composite material first increases and then decreases, and finally the best process parameters (as above) are selected to obtain the best mechanical properties.

[0017] Further, the oxygen content in step (3) is less than 100 ppm.

[0018] Further, the process parameters of direct aging heat treatment are: aging temperature: 325 ℃; holding time: 2h; cooling method: air cooling. The selection of aging temperature and aging time has a great influence on the aluminum matrix composite and mechanical properties. If the aging temperature is too low and the aging time is too long, the strengthening phase is easy to coarsen and distribute unevenly, and the maximum strength of the composite material will decrease. Through the direct aging heat treatment experiment (300 ℃-375 ℃, holding for 1 h), the aging temperature is determined as 325 ℃, and the aging hardening curve at this temperature is established to determine the best aging time as 2 h.

[0019] The high-modulus high-strength aluminum matrix composite material and the preparation method thereof provided in the above technical solution, by the composite regulation of nano-sized TiN and Si3N4 hybrid reinforcing particles and a specific heat treatment process, a new type of high-modulus high-strength laser additive manufacturing aluminum matrix composite material is prepared. The high-modulus high-strength aluminum matrix composite material prepared by the method not only has excellent forming performance, but also has excellent mechanical properties, which can meet the demand for high-performance materials in the fields of aerospace, automobiles and ships.

[0020] The prepared selective laser melting forming high-modulus high-strength aluminum matrix composite material has the following advantages:

[0021] (1) Uniform distribution of reinforcing phase: ball milling process ensures uniform dispersion of nanoparticles in the matrix, effectively avoiding the agglomeration phenomenon in the laser melting forming process;

[0022] (2) High forming quality: optimized laser parameters (laser power, scanning speed, layer angle) effectively suppress pores and cracks, and the density of the composite material part is ≥99.2%;

[0023] (3) Excellent mechanical properties: after direct aging heat treatment, the tensile strength of the composite material is 586.4 MPa, the yield strength is 568.9 MPa, and the modulus is 78.7 GPa. Compared with the as-deposited substrate (tensile strength of 403.2 MPa, yield strength of 327.6 MPa, and modulus of 55.8 GPa), the tensile strength is increased by 45%, the yield strength is increased by 74%, and the modulus is increased by 41%. It is expected to meet the demand for lightweight high-modulus high-strength materials in the field of aerospace and other fields. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 are morphology diagrams of the substrate aluminum alloy powder and the aluminum matrix composite powder;

[0025] Figure 2 are microstructure diagrams of different materials;

[0026] Figure 3 are hardness change curves of direct aging temperature and time;

[0027] Figure 4 are tensile mechanical property curve comparison diagrams of different materials. DETAILED DESCRIPTION

[0028] In order to make the purpose and advantages of the present application clearer and more apparent, the present application will be specifically described below in combination with examples. It should be understood that the following text is only used to describe one or several specific embodiments of the present application, and does not strictly limit the specific protection scope requested by the present application.

[0029] The present embodiment is a preparation method of high-modulus high-strength aluminum matrix composite material, which specifically comprises the following steps:

[0030] (1) The average particle size of the Al-Mg-Si-Mn-Sc-Zr alloy powder is 26.74 μm, and the specific ratio of the alloying elements is as follows: 8 wt.% of Mg element, 1.4 wt.% of Si element, 0.5 wt.% of Mn element, 0.6 wt.% of Sc element, 0.3 wt.% of Zr element, and the rest is Al element. 1 wt.% of nano-TiN and 1 wt.% of nano-Si3N4 particles are introduced into the alloy, and the average size of TiN and Si3N4 particles is 80 nm. The ball milling mixing process is completed in a planetary ball mill, and the mixing speed is 200 rpm for 2 h. The ball milling process strategy is to run for 30 min and stop for 5 min. The total running time of the machine is 2.25 h. The ball-to-material ratio is set to 7:1 to ensure uniform mixing of TiN particles, Si3N4 particles and aluminum alloy matrix powder, forming an aluminum-based composite powder material synergistically reinforced by TiN and Si3N4, as shown in Figure 1 .

[0031] (2) A cuboid model with dimensions of 85 mm x 12 mm x 10 mm was constructed in a computer using three-dimensional UG software, the model was converted into an STL file, and was imported into a slicing software for slicing processing, and the data was imported into a selective laser melting device for subsequent printing processing.

[0032] (3) An aluminum alloy sample without particles and an aluminum matrix composite with 1wt.% TiN + 1wt.% Si3N4 were prepared using selective laser melting technology. A selective laser melting device with a Concept laser M2 cusing model was used, and an AlSi10Mg substrate with a thickness of 20 mm was selected for processing. The substrate was sandblasted pretreated to ensure the uniformity of the first layer of powder. Subsequently, a constant scanning strategy (rotating 67° between adjacent layers) was used to deposit the sample on the substrate. During the manufacturing process, 99.999% pure argon gas was introduced into the chamber to keep the oxygen content below 100 ppm. The powder layer thickness was set to 40 μm, the laser power was 350 W, the scanning speed was 1000 mm / s, and the scanning pitch was 100 μm.

[0033] (4) The aluminum alloy matrix and TiN + Si3N4 synergistically reinforced aluminum matrix composite prepared by the above-mentioned example process have a density of 99.15% and 99.47%, respectively, and excellent forming quality without defects such as atmospheric pores and cracks. The material shows excellent forming performance. At the same time, Figure 2 The microstructure of the aluminum alloy matrix composite is further disclosed, revealing the distribution of nano-TiN particles and nano-Si3N4 particles and the morphology of precipitated phases.

[0034] (5) Tensile test was performed on the aluminum alloy matrix sample and TiN + Si3N4 synergistically reinforced aluminum matrix composite sample prepared by selective laser melting process, and the tensile strength of the matrix was 403.2 MPa, the yield strength was 327.6 MPa, the elongation was 7.7%, and the modulus was 55.8 GPa; the room temperature tensile strength of the TiN + Si3N4 synergistically reinforced aluminum matrix composite was 446.6 MPa, the yield strength was 412.3 MPa, the elongation was 3.8%, and the modulus was 75.1 GPa.

[0035] (6) The TiN and Si3N4 synergistically reinforced aluminum matrix composite parts were heat treated, and the aging temperature was determined to be 325 ℃ through direct aging heat treatment experiment (300 ℃-375 ℃, holding for 1 h), and the aging hardening curve at this temperature was determined to determine the best aging time of 2 h, as Figure 3The precision air blast drying oven was then heated to 325°C, and then the parts were put into the drying oven, and taken out after 2 h of holding time, and cooled at room temperature. The tensile test results show that after heat treatment at 325°C for 2 h, the tensile strength of the aluminum-based composite material at room temperature is 586.4 MPa, the yield strength is 568.9 MPa, the elongation is 1.9%, and the modulus is 78.7 GPa. Compared with the as-deposited substrate (tensile strength of 403.2 MPa, yield strength of 327.6 MPa, and modulus of 55.8 GPa), the tensile strength is increased by 45%, the yield strength is increased by 74%, and the modulus is increased by 41%, as shown in Figure 4

[0036] The embodiments of the present application are described in detail above with reference to the examples, but the present application is not limited to the above-described embodiments. For those skilled in the art, after learning the content described in the present application, a number of equivalent transformations and substitutions can be made without departing from the principles of the present application, and these equivalent transformations and substitutions should also be considered to be within the scope of the present application.​

Claims

1. A method of making a high modulus high strength aluminum matrix composite material, characterized by, The high-modulus high-strength aluminum-based composite material comprises an aluminum alloy matrix powder and reinforcing phase particles; The aluminum alloy matrix powder comprises, in mass percentage: Mg: 7-9 wt.%, Si: 0.4-2.5 wt.%, Mn: 0.3-0.8 wt.%, Sc: 0.5-0.7 wt.%, Zr: 0.2-0.5 wt.%, and the balance of Al and inevitable impurities; The reinforcing phase particles comprise TiN and Si3N4 nanoparticles, wherein the TiN is added in an amount of 1 wt.% of the total mixture, and the Si3N4 is added in an amount of 1 wt.% of the total mixture. The preparation method comprises the following steps: uniformly mixing the aluminum alloy matrix powder and the reinforcing phase particles by a ball milling process to obtain an aluminum-based composite powder mixture; then performing a forming experiment on the mixture by a selective laser melting process to obtain a sample material; and finally directly aging and heat treating the sample material to obtain the aluminum-based composite material. The process parameters of the direct aging and heat treatment are as follows: aging temperature: 325 ℃; holding time: 2 h; and cooling mode: air cooling.

2. The method of producing a high modulus high strength aluminum matrix composite of claim 1, wherein: The particle size distribution of the aluminum alloy matrix powder is 15-53 μm; and the average particle size of the TiN and Si3N4 nanoparticles in the reinforcing phase particles is 80 nm.

3. The method of producing a high modulus high strength aluminum matrix composite of claim 1 wherein, The parameters of the ball milling process are as follows: ball-to-material ratio: 7:1; ball milling speed: 200 r / min; ball milling time: 2-3 h; and high-purity argon is filled in the ball milling tank during the ball milling process, and the ball milling tank is sealed to ensure that the oxygen content is less than 100 ppm.

4. The method of producing a high modulus high strength aluminum matrix composite of claim 1 wherein, The steps of the selective laser melting process comprise: (1) constructing a three-dimensional model of a target sample, and then performing layering treatment by using a slicing software, and setting the single-layer powder spreading thickness to be 40 μm; (2) selecting an AlSi10Mg substrate with a thickness of 20 mm, and controlling the surface roughness Ra of the substrate after sandblasting treatment to be 3.2-6.4 μm, so as to ensure uniform spreading of the first layer of powder; (3) performing the selective laser melting forming process in an argon protective atmosphere, and the process parameters are as follows: laser power: 250-450 W; scanning speed: 900-2500 mm / s; scanning interval: 100 μm; powder layer thickness: 40 μm; and scanning strategy: zonal strip scanning, and the layer-to-layer corner angle is 67°-90°.

5. The method of producing a high modulus high strength aluminum matrix composite of claim 4, wherein: In step (3), the laser power is 350 W, the scanning speed is 1000 mm / s, and the layer-to-layer corner angle is 67°.

6. The method of producing a high modulus high strength aluminum matrix composite of claim 4, wherein: In step (3), the oxygen content needs to be less than 100 ppm.

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