固溶时间对Al-7Si-0.4Mg合金Si颗粒形貌和力学性能的影响

Effects of Solution Holding Time on Si Morphology and Mechanical Properties of Al-7Si-0.4Mg Alloys

在535℃对Al-7Si-0.4Mg合金在不同保温时间下进行固溶处理,分别用OM、SEM、DSC分析研究固溶保温时间对合金中微观Si颗粒形貌、断口形貌和析出相行为以及合金力学性能的影响。结果表明,保温1 h合金中的Si颗粒能实现熔断和分离,当保温时间达到3 h时能获得最佳形貌的Si颗粒,此后延长保温时间则会出现过烧,恶化Si颗粒形貌。固溶保温3 h的合金具有最佳的强度和塑性,表现出最优的综合力学性能,能析出稳定的强化相Mg2Si粒子,实现Si、Mg等元素的均匀化分布。

The solution treatment on Al-7Si-0.4Mg alloys at 535 ℃ for various holding time was carried out.The effectc of solution holding time on Si particle morphology,fracture morphology,precipitation phase behavior and mechanical properties of the alloy were analyzed by OM,SEM and DSC,respectively.The reulsts show that Si particles can be broken off and separated in solution holding time of 1 h,and the best improvement of the Si morphologies can be obtained in solution holding time of 3 h.Prolonging holding time will result in over-burning and the deterioration of Si morphology appears.The alloys for the solution time of 3 h have the optimal strength and plasticity,exhibiting the best mechanical properties.In the alloys for the solution time of 3 h,the stable strength phase Mg2Si separates out and the homogenization of Si and Mg elements can be obtained.