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用圆锥铜模制备不同冷却速率下Mg-14Zn-5Al合金的铸态试样,研究冷却速率对合金的铸态组织以及不同原始铸态组织对其部分重熔行为的影响。结果表明:随着冷却速率的减慢,Mg-10Zn-5Al合金的铸态组织经历了细小的枝晶→粗大枝晶→等轴晶的过程;由枝晶向等轴晶转变的原始组织经部分重熔后,其平均晶粒尺寸呈先增大后减小再增大的变化趋势,其圆整度呈先减小后增大的变化趋势,固相率变化不大;当原始组织以细小的等轴晶为主时,其重熔后的组织较好,此时Mg-14Zn-5Al合金的平均晶粒尺寸为44.5~48.6μm,圆整度为1.32~1.43,固相率在60%左右。
The as-cast samples of Mg-14Zn-5Al alloy with different cooling rates were prepared by using conical copper molds. The effects of cooling rate on the as-cast microstructure and partial remelting behavior of different as-cast alloys were investigated. The results show that as the cooling rate slows down, the as-cast microstructure of Mg-10Zn-5Al alloy undergoes the process of small dendrite → coarse dendrites → equiaxed grains; the original structure transformed from dendrite to equiaxed grains passes through part After remelting, the average grain size first increases, then decreases and then increases. The roundness first decreases and then increases, and the solid fraction does not change much. When the original structure is small The average grain size of Mg-14Zn-5Al alloy is 44.5-48.6μm, the roundness is 1.32-1.43 and the solid fraction is 60% about.