Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第27卷    第12期    总第225期    2017年12月

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文章编号:1004-0609(2017)-12-2443-08
混合稀土对过共晶Al-20Si合金显微组织与力学性能的影响
李庆林1, 2,李斌强1,李进宝1,兰晔峰1, 2,夏天东1, 2

(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)

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96 μm减小到41 μm,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%。

 

关键词: Al-20Si合金;混合稀土;显微组织;力学性能

Effect of mischmetal on microstructure and mechanical properties of hypereutectic Al-20Si alloy
LI Qing-lin1, 2, LI Bin-qiang1, LI Jin-bao1, LAN Ye-feng1, 2, XIA 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, China

Abstract: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-20Si 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.

 

Key words: Al-20Si alloy; mischmetal; microstructure; mechanical property

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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