Magnesium-contained high-silicon aluminum alloys structural materials and manufacture method thereof

Abstract

The magnesium-contained high-silicon aluminum alloys for use as structural materials, including profiles, bars, sheets, and forgings, are manufactured by a process including the steps of: casting an alloy ingot by direct chill casting, preheating the ingot to disperse eutectic Si phase particles, and thermal-plastic processing and heat-treating to obtain the product with a final shape and a modified microstructure. The aluminum alloys contain 0.2˜2.0 wt % of Mg and 8˜18 wt % of Si, and have homogeneous and fine microstructure, wherein the aluminum matrix is equiaxed with an average grain size less than 6 μm, and the silicon and second phase particles are dispersed with an average size less than 5 μm. Without adding any modifiers, they are low-costly produced by incorporating the direct chill casting with thermal-plastic processing and heat treatment, which give rise to good plasticity and relatively high strength.

Description

BACKGROUND OF THE PRESENT INVENTION[0001]1. Field of Invention[0002]The present invention relates to aluminum alloys and their method of preparation, and more particularly to magnesium-contained high-silicon aluminum alloys for use as structural materials, and the manufacture method thereof.[0003]2. Description of Related Arts[0004]Aluminum-silicon alloys (Al—Si alloys), especially those with high silicon content, are widely used in car and aviation industries, due to their low density, high wear resistance, high anti-corrosiveness, and low thermal expansion coefficient. With the common solidification method for preparation of Al—Si alloys, there usually appear large silicon particles and eutectic plates, resulting in a dramatically increased brittleness of the alloys. Thus, it is difficult to improve the solidified microstructure and to obtain various shaped high-performance structural materials through subsequent plastic deformation, which poses a bottleneck for more general appli...

AI Technical Summary

Benefits of technology

[0006]An object of the present invention is to provide high-silicon aluminum alloys (Al—Si alloys) that contain magnesium (Mg) and have good plasticity and high strength for use as structural materi...

Problems solved by technology

With the common solidification method for preparation of Al—Si alloys, there usually appear large silicon particles and eutectic plates, resulting in a dramatically increased brittleness of the alloys.

Thus, it is difficult to improve the solidified microstructure and to obtain various shaped high-performance structural materials through subsequent pla...

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