Microstructural evolution and precipitation behavior of Al-7Si-3Cu alloy prepared under 5 GPa  

作　　者：Ning Fang Chunming Zou Zunjie Wei Hongwei Wang Jiahan Chen Zongyue Jin 

机构地区：[1]Key Laboratory for Precision Hot Processing of Metals,Harbin Institute of Technology,150001 Harbin,China

出　　处：《Journal of Materials Science & Technology》2023年第28期138-150,共13页材料科学技术（英文版）

基　　金：the National Natu-ral Science Foundation of China(Nos.52231002 and 51774105);the Touyan Innovation Team Program(No.XNAUEA5640208420);the Foundation of National Key Laboratory for Precision Hot Pro-cessing of Metals(No.6142909210202).

摘　　要：This paper presents a systematic investigation of the microstructural evolution and mechanical proper-ties of Al-7Si-3Cu alloys prepared under high pressure of 5 GPa.It is found that the dendritic structure disappears due to the enhanced stability of the growth interface under high pressure.Meanwhile,a con-siderable solute-induced modification effect is achieved in the eutectic Si.Besides,unconventional larger eutectic colonies and ultrafine nanocrystalline eutectics are observed within the intragranular area.Com-bined with detailed microstructural characterization,the crucial role of high pressure on the evolution of these isolated phases is discussed.The study also explores the precipitation behavior and strengthening mechanisms of alloys prepared under direct aging and solution-aging treatments.Upon the direct aging treatment,θ’phases,coarse Al 2 Cu particles,and Si particles form simultaneously in the matrix owing to the increased solid solubility of alloying elements,which results in the highest mechanical properties with a microhardness of 132.8 HV and compressive stress of 715 MPa.Solution-aging treatment leads to the segregation of Si onθ’phases,which proved to be energetically favorable according to first-principles calculations.This work provides new insights into the microstructural optimization of aluminum-silicon-based alloys through high-pressure manipulation and paves the way for further industrial applications.

关 键 词：Al-Si-Cu alloy High pressure Nanocrystalline eutectics PRECIPITATES Mechanical properties 

分 类 号：TG316[金属学及工艺—金属压力加工] TG146.11[一般工业技术—材料科学与工程]