Preparation method of nanometer bimodal isomeric aluminum-magnesium alloy

Abstract

The invention belongs to the field of preparation of metal materials, and particularly relates to a preparation method of a nanometer bimodal isomeric aluminum-magnesium alloy. The preparation methodcomprises the following steps of: firstly carrying out homogenization treatment on a metal block obtained after smelting and casting by using a high-pressure torsion severe plastic deformation method,then carrying out thermal deformation treatment so as to eliminate casting defects, carrying out solution hardening to eliminate the second phase separated out, and preparing a nanocrystalline material with the average grain size of about 80nm by using a coarse-grained aluminum-magnesium alloy sheet, finally using a pulse laser for the fixed point positioning formation of ultrafine crystal / nanocrystalline on the material, and thus, the aluminum-magnesium alloy material with strong plasticity meeting specific requirements can be prepared according to the requirements of a workpiece. A laser temperature-controlled time-controlled point heating technology can be used for controlling the fixed point positioning and quantitative formation of ultrafine crystal / coarse crystals on the basis of anoriginal nanocrystalline substrate. The workpiece can be customized according to the performance requirements of the product, so that the plasticity and strength can be most effectively combined.

Description

technical field [0001] The invention belongs to the field of metal material preparation, in particular to a method for preparing a nano bimodal heterogeneous aluminum-magnesium alloy. Background technique [0002] Aluminum is the most abundant metal on the earth. Aluminum alloy has low density, high specific strength, good plasticity, excellent processing performance, good electrical conductivity, thermal conductivity and corrosion resistance. Magnesium and magnesium alloys are currently the lightest metal structural materials, which have the advantages of low density, high specific strength, high specific stiffness and easy recycling. Among many aluminum alloys, aluminum-magnesium alloys have broad application prospects in many fields due to their high strength / weight ratio, excellent corrosion resistance and weldability. As we all know, the strength and plasticity of metal materials are often not compatible: High strength corresponds to low plasticity, and vice versa, suc...

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Problems solved by technology

This method is very sensitive to process parameters, and the performance is not easy to repeat; the patent [public number: CN105951132A, public date: 2016.09.21] disclosed "a method of electrochemical deposition preparation of submicron-scale bimodal ultrafine-grained nickel material" solved The technical problem is to provide a submicron bimodal ultrafine nickel material with good matching between strength and plasticity and simple preparation process. This method involves complex chemical and physical processes and high cost; patent [public number: CN106011422A, open Day: 2016.10.12] published "high-strength steel with double-peak scale ferrite structure and its low-cost preparation method" uses ordinary low-carbon steel as raw material plate, through cold deformation + two-phase zone quenching treatment, obtained fine The quasi-polygonal ferrite grains are distributed around the bimodal structure of the coarse polygonal ferrite grains. The coarse-grained regions account for the majority of the material obtained by this method, and the strength is very different from that of nano-crystalline materials; patent [Publication number: CN106929764A, Publication date: 2017.07.07] The disclosed "a preparation method of nanocrystalline / ultrafine-crystalline biphasic bimodal bulk material" prepares single-phase materials by hot pressing and sintering, and then obtains a controllable structure by heat treatment. Nano / ultrafine-grained biphasic bimodal iron-based bulk, the material obtained by this method has natural defects in density and purity due to powder sintering

[0005] To sum up, the methods for preparing nano-bimodal heterogeneous alloys at this stage are mainly sensitive to process parameters and difficult to control; the reaction is complicated and the cost is too high; the ratio of coarse and fine grains does not meet the expected requirements; the density and purity are not enough.

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