Al-10Sr变质剂状态、变质温度及变质时间对ZL114A合金组织的影响

Effects of Al-10Sr modifiers with different states,modification temperature and holding time on microstructure of ZL114A alloy

制备了不同处理状态(常规铸态、快速凝固态、轧制变形态)的Al-10Sr中间合金作为变质剂,其中加入Sr的质量分数为0.02%。研究了不同尺寸的Al4Sr相、变质温度及变质时间对ZL114A显微组织的影响。结果表明:常规铸态、快速凝固态的Al-10Sr变质ZL114A合金在750℃分别保温30min、15min时获得最佳变质效果,轧制态Al-10Sr变质的ZL114A合金在720℃时、保温15min时共晶硅为珊瑚状,变质效果最好;Al4Sr的尺寸越小,变质效果越好,而且Al4Sr的尺寸越小,熔体温度越高,Sr变质的孕育期越短。

Al-10Sr master alloy with different states （conventional as-cast state, rapid-solidified state and rolled state） were prepared as modifiers in the experiments, with 0.02 wt. % of Sr. The effects of the size of AI4 Sr phase, modification temperature and holding time on the microstructure of ZLll4A alloy were investigated. Results show that the optimized conditions of ZL114A alloy modified by conventional as-cast and rapid-solidified AI-10Sr master alloy were holding 30 min and 15 min at 750 ℃, respectively. The rolled AI-10Sr made modification treatment has significant effect at 720 ℃ for 15 rain, as it caused the eutectic silicon to transform into coral-like. The smaller the size of A14 Sr phase, the better modification efficiency was obtained. Moreover, the smaller size of A14 Sr and higher melt temperature resulted in the shorter incubation time.