Al-7Si合金在热处理过程中的显微结构演变  

Microstructure development during heat treatment in an Al-7Si Alloy

作　　者：龙慧池[1] 陈江华[1] 刘春辉[1] 李祥亮[1] 

机构地区：[1]湖南大学材料科学与工程学院高分辨电镜中心,湖南长沙410082

出　　处：《电子显微学报》2013年第1期18-24,共7页Journal of Chinese Electron Microscopy Society

基　　金：国家重点基础研究发展计划资助项目(No.2009CB623704);国家自然科学基金资助项目(No.51171063);湖南省高校科技创新团队项目;湖南省研究生科研创新项目;Gatan中国博士生奖学金

摘　　要：本文利用扫描电子显微镜(SEM)和高分辨透射电子显微镜(HRTEM)研究了固溶处理和时效处理过程中铝硅二元合金中硅颗粒、析出相及硅颗粒与铝基体界面处的微观结构变化特征。研究结果表明:随着固溶时间的延长,硅颗粒的形态由树枝状逐渐变成椭球状和球状;时效过程中,溶入α-Al基体中的硅原子会在铝基体中聚集,形核并形成沿铝基体{111}面生长的硅析出相,同时还会在硅颗粒上析出一层硅的纳米孪晶,这些纳米孪晶会随着时效时间的延长不断长大。硅的孪晶壳层中存在大量孪晶和其他缺陷,除了常见的SiΣ3(111)孪晶外,观察到的孪晶类型还包括多重孪晶,如五重孪晶。Microstructure developments of eutectic silicon particles, silicon precipitates and interfaces between eutectic silicon particles and A1 matrix in an A1-6.86wt. % Si alloy during heat treatment were studied by means of X-ray diffraction, scanning electron microscopy and high resolution transmission electron microscopy. Eutectic silicon particles of branch-like morphology became spheroidized and coarsened to some extent with the extending of solution treatment time. A certain amount of Si atoms dissolved in the A1 matrix would aggregate, nucleate and grow into silicon precipitates in the matrix and at grain boundaries as well during artificial aging. Silicon precipitates in the matrix lied on.the {111} planes of the A1 matrix. Silicon precipitates on the euteetie silicon particles grew larger with aging time. A large number of twins and other crystal defects were presented in the nano-sized silicon precipitates on the eutectic silicon particles. In addition to ordinary Sib∑3 （111 ） twins, some multiple twins such as five-fold twins were also observed.

关 键 词：铝硅合金 硅颗粒 析出相 孪晶 

分 类 号：TG166.3[金属学及工艺—热处理]