New technique for preparing A356 alloy semisolid slurry and its rheo-diecast microstructure and properties  

新工艺制备A356铝合金半固态浆料及其流变压铸组织和性能

作　　者：Ming-fan QI Yong-lin KANG Yu-zhao XU Jing-yuan LI Ai-sen LIU 祁明凡;康永林;徐玉昭;李静媛;刘爱森(北京科技大学材料科学与工程学院,北京100083;森特士兴集团股份有限公司,北京100176)

机构地区：[1]School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China [2]Center International Group Co.,Ltd.,Beijing 100176,China

出　　处：《Transactions of Nonferrous Metals Society of China》2021年第7期1868-1884,共17页中国有色金属学报（英文版）

基　　金：the financial supports from the National Natural Science Foundation of China(Nos.52005034,52027805);the Beijing Postdoctoral Research Foundation(No.2021-ZZ-073);the China Postdoctoral Science Foundation Funded Project(2021M691860);the Fundamental Research Funds for the Central Universities(No.FRF-TP-18-043A1);the Zhuhai Industry-University-Research Cooperation Project(No.ZH22017001200176PWC).

摘　　要：A new technique for preparing semisolid slurry,namely,distributary-confluence runner(DCR),was combined with die-casting(DC)to conduct rheological die-casting(R-DC)of A356 alloy.The mechanism of DCR for semisolid slurry preparation was determined via numerical simulations and experiments.The microstructure and mechanical properties of A356 alloys prepared via DC and R-DC were studied.High-quality slurry containing numerous primary α-Al(α1-Al)with an average size of 49μm and a shape factor of 0.81 could be prepared via DCR.Simulation results indicated that the unique flow state and physical field changes during slurry preparation were conducive to accelerating the uniformity of melt temperature and composition fields,nucleation exfoliation,and spherical growth.Compared with the alloy prepared via DC,the tensile strength,yield strength,and elongation of A356 alloy prepared via R-DC increased by 19%,15%,and 107%,respectively.将新开发的分流汇合浇道(DCR)半固态浆料制备工艺与压铸技术结合,实现A356铝合金流变压铸成形。结合数值模拟与实验,探讨DCR工艺制备半固态浆料机理;研究DCR流变压铸和传统压铸A356铝合金的显微组织和力学性能。结果表明,DCR工艺可以制备内部含有大量初生α-Al晶粒且其平均尺寸为49μm、形状因子为0.81的高品质半固态浆料。数值模拟结果表明,DCR工艺制备半固态浆料过程中其独特的流动状态和物理场变化有利于加速熔体温度场和成分场的均匀、晶核剥落和球状长大。和传统压铸相比,DCR流变压铸A356铝合金的抗拉强度、屈服强度和伸长率分别提高了19%、15%和107%。

关 键 词：semisolid slurry A356 alloy distributary-confluence runner rheological die-casting microstructure tensile properties 

分 类 号：TG146.21[一般工业技术—材料科学与工程]