Preparation method of high-strength and high-toughness a356.2 aluminum-based composite material for wheel hub

Abstract

The invention discloses a method for preparing a high-strength and high-toughness A356.2 aluminum-based composite material for a wheel hub. The preparation process steps are as follows: (graphene+HfB 2 )‑Aluminum intermediate alloy wire preparation; A356.2 alloy smelting, intermediate alloy addition, refining, pressure casting; solution aging treatment; shot peening, finishing, alkali pickling, anodizing, finished product packaging. Through the above method, the two systems of two-dimensional nanostructured graphene nucleation and in-situ self-generated nucleation are introduced to complement each other, the second phase of silicon in A356.2 is refined on a multi-dimensional scale, and the multi-dimensional nanostructure is simultaneously strengthened on aluminum matrix composites. The invention solves the limitation problems such as insufficient strength, hardness, plasticity and toughness in the application process of the commonly used A356.2 alloy of the wheel hub, and the low-pressure casting process produces graphene / HfB 2 / Aluminum composite materials have excellent comprehensive properties, which meet the further weight reduction requirements of lightweight.

Description

technical field [0001] The invention relates to a high-strength and high-toughness A356.2 aluminum-based composite material for a wheel hub, in particular to a preparation method of a high-strength and high-toughness A356.2 aluminum-based composite material for a wheel hub. Background technique [0002] Among the cast aluminum alloys, the representative alloy of the subeutectic in the Al-Si system that has received widespread attention due to its excellent performance is A356.2, which was first developed and applied in the United States as a cast aluminum alloy. [0003] By adding a variety of modifiers to the A356 alloy to improve the morphology and distribution of phases in the alloy, the phase morphology of the modified alloy changes, leading to a certain degree of performance improvement. Studies have shown that sodium salt as the initial modifier of Al-Si alloy has achieved a good modification effect, making the coarse plate-shaped silicon phase into a relatively regula...

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Problems solved by technology

Existing problems, complex process, high production cost, and the preparation process and application background of the material are completely different from this patent

Chinese patent application 201810952973.3 A graphene-enhanced Al-Si-Mg cast aluminum alloy and its preparation method, patent application 201911292058.7 A graphene-enhanced Al-Si cast aluminum alloy, its preparation method and patent application 202010460438.3 A graphene-enhanced aluminum alloy In the eutectic aluminum-silicon alloy and its preparation method, graphene and metal are simply mixed and smelted, and the poor wettability of graphene / aluminum will make it difficult to achieve the desired effect. The patent does not see significant refinement of the silicon phase, and the average size is as small as several Ten microns, the maximum can reach about a hundred microns, and the tensile strength value is only 150-180MPa

Chinese patent application 201811331019.9 a graphene rare earth cerium reinforced Al-Si-Mg cast aluminum alloy and its preparation method and Chinese patent application 201811331020.1 a graphene rare earth scandium synergistically reinforced Al-Si-Mg cast aluminum alloy and its preparation method, Metal particles and graphene particles are directly mixed and smelted, which is difficult to solve the problem of poor interface wettability between graphene and aluminum. At the same time, high-purity inert gas protection is used for vacuum arc melting, the production scale is small, the cost is high, and the graphene has the effect of refining the silicon phase. Not significant, while the tensile strength index is only 230-250MPa

With the continuous improvement of automobile lightweight requirements, higher requirements are put forward for the comprehensive performance of materials. Due to the microstructure characteristics such as coarse eutectic silicon phase in A356.2 alloy, it is difficult for the mechanical properties of the alloy to meet the needs of high-standard components.

The compounding of multi-dimensional materials fundamentally solves the problems of easy fading, low absorption rate, pinholes caused by gas absorption and other problems that limit product quality in the traditional modification method of alloys.

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