Effect of super vacuum assisted high pressure die casting on the repeatability of mechanical properties of Al-Si-Mg-Mn die-cast alloys
Effect of super vacuum assisted high pressure die casting on the repeatability of mechanical properties of Al-Si-Mg-Mn die-cast alloys
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DOI：
10.1016/j.jmatprotec.2018.10.030
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发表时间：
2019-04-01
影响因子：
6.3
通讯作者：
Ji, Shouxun
中科院分区：
文献类型：
--
作者：
Dong, Xixi;Zhu, Xiangzhen;Ji, Shouxun
两级超真空（19mbar）辅助高压压铸（HPDC）是通过同时从模腔和模套中抽气实现的。研究了超真空辅助HPDC对Al-Si-Mg-Mn压铸合金拉伸性能重复性的影响，并与常规HPDC相比较。定量Weibull分析证实，超真空辅助HPDC提高了合金拉伸性能的可重复性。数据和偏差分析证实，超真空辅助HPDC使铸态合金的极限抗拉强度和塑性分别提高了5.6%和43%，固溶时效处理后合金的塑性提高了21%。塑性和拉伸性能的显著提高是由于超真空辅助HPDC处理合金的孔隙体积分数和孔隙尺寸的降低。缺陷尺寸的减小可以改善铸件的应力分布，延缓裂纹的产生。因此，超真空辅助高压直流压铸合金的抗拉强度和塑性得到了提高。
Two-stage super vacuum (19 mbar) assisted high pressure die casting (HPDC) was achieved by evacuating from the die cavity and the shot sleeve simultaneously. The effect of super vacuum assisted HPDC on the repeatability of the tensile properties of Al-Si-Mg-Mn die-cast alloy was investigated in comparison with conventional HPDC. The quantitative Weibull analysis confirmed that super vacuum assisted HPDC improved the repeatability of the tensile properties of the alloy. The data and deviation analysis verified that super vacuum assisted HPDC considerably decreased the fluctuations of the ductility of the alloy by 71% in as-cast state and 84% after solution and ageing treatment The results also showed that super vacuum assisted HPDC improved the ultimate tensile strength and ductility of the as-cast alloy by 5.6% and 43%, respectively, and increased the ductility of the alloy by 21% after solution and ageing treatment. The significant improvements of ductility and the repeatability of tensile properties were originated from the decrease of porosity volume fraction and porosity size in the alloy processed by super vacuum assisted HPDC. The reduction of defect size can improve the stress distribution and retard the crack initiation in castings. Therefore, the tensile strength and ductility were enhanced in the die-cast alloy processed by super vacuum assisted HPDC.