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

来源期刊:中国有色金属学报(英文版)2021年第7期

论文作者:祁明凡 康永林 徐玉昭 李静媛 刘爱森

文章页码:1868 - 1884

关键词:半固态浆料;A356铝合金;分流汇合浇道;流变压铸;显微组织;拉伸性能

Key words:semisolid slurry; A356 alloy; distributary-confluence runner; rheological die-casting; microstructure; tensile properties

摘    要: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49 μm、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%。

Abstract: 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 49 μm 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.

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