混合稀土对过共晶Al-20Si合金显微组织与力学性能的影响  

Effect of mischmetal on microstructure and mechanical properties of hypereutectic Al-20Si alloy

作　　者：李庆林[1,2] 李斌强[1] 李进宝[1] 兰晔峰[1,2] 夏天东[1,2] LI Qing-lin1＇ 2, LI Bin-qiang1, LI Jin-baol, LAN Ye-fengl＇ 2, X1A Tian-dong1＇ 2(1. School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China; 2. State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, Chin)

机构地区：[1]兰州理工大学材料科学与工程学院,兰州730050 [2]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050

出　　处：《中国有色金属学报》2017年第12期2443-2450,共8页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51561021);甘肃省自然科学基金资助项目(1606RJZA024);甘肃省高校科研基金资助项目(2015B-035)~~

摘　　要：采用光学显微镜、扫描电子显微镜、电子探针及力学性能测试,研究了不同比例的混合稀土Pr和Y对过共晶Al-20Si合金显微组织与力学性能的影响。结果表明:Al-20Si合金中添加稀土Pr和Y能使合金中粗大的块状及五瓣星状初生Si变质为细小的块状和部分粒化;当Pr和Y按质量比1:1的比例混合(0.5%Pr、0.5%Y,质量分数)时,细化效果最为显著,初生Si尺寸由96μm减小到41μm,减小57.3%,共晶Si由粗大的针片状变质为类蠕点状;此时,合金的抗拉强度由93 MPa提高到143 MPa,伸长率从1.12%提高到2.79%,分别提高53.8%和149%。By optical microscopy, scanning electron microscopy, electron probe analysis and mechanical property test, the effects of mischmetal Pr and Y on the microstructure and mechanical properties of hypereutectic Al-20 Si alloy were investigated. The results show that the addition of mischmetal Pr and Y can effectively modify the primary Si from coarse polygonal and star-like shape to fine blocky shape with smooth edges and corners. When the mass ratio of mischmetal Pr and Y is 1：1（0.5%Pr, 0.5%Y（mass fraction））, the consequence of modification is the best on primary silicon and eutectic silicon, the size of primary silicon reduces by 57.3% from 96 μm to 41 μm. In addition, the morphology of eutectic silicon changes from coarse platelet-like/needle-like structure to fine fibrous structure and worm-like. The ultimate tensile strength increases by 53.8% from 93 MPa to 143 MPa, and the elongation increases by 149% from 1.12% to 2.79%, respectively.

关 键 词：AL-20SI合金 混合稀土 显微组织 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]