电脉冲时间对铸造ZA12合金凝固组织和性能的影响

以ZA12合金为实验材料，在合金的凝固过程中进行了脉冲电流处理，研究电脉冲时间对作用结果的影响。实验结果表明，就细化合金的凝固组织、改善力学性能而言，在合金凝固的整个过程都进行脉冲电流处理比仅在合金凝固的前半段进行处理的效果要好。结合ZA12合金的凝固特性和电流对金属熔体的作用机制进行分析。认为在合金凝固后半段施加的脉冲电流处理促进了枝晶之间液体的流动。增强了枝晶间液体的补缩能力，并且导致部分小的枝晶熔断。从而进一步抑制了枝晶的生长．得到更均匀细小的凝固组织。从而对合金力学性能的改善效果也更为显著。

Influence of Electropulsing Time on Solidification Structure and Property of the Casting ZA12 Alloy

Electric current pulse was applied during the solidification of casting ZA12 alloy and the influence of electropulsing time was studied.The result show that in the experiments in which the electropulsing was stopped at the half way of the solidification process,the colony size was obviously larger than that for electropulsing throughout the entire process and it is opposite for the tensile strength.Considering the effects of electropulsing on the melt alloy and the solidifecation characteristic of ZA12 alloy,some explanation was made.The following effects of electric current pulse on the melt alloy during the second half of the soli dification,including the enhancement of convection among particle,the melt of some smalldendrites;the equalization of temperature fields and solute fields,and the restriction of growth of dendrites,may lead to the experimental result mentioned above.