凝固条件对半固态合金组织影响的研究

Influence of different solidification conditions on microstructures of semi-solid alloy

对不同温度下的半固态ZA9合金凝固过程中的传热和流动行为进行模拟,测量出合金在不同工艺下的温度场分布,获取不同温度场下的金相图,并计算出其对应温度下的凝固率和晶粒的形状特征尺度。结果表明:温差较大的晶粒成型速度较快,合金的传热性较高;对合金采用机械振动和机械搅拌后,枝晶碎断,使晶粒大大细化,半固态合金内部的温度场分布趋于均匀,从而改善合金组织性能。

By simulating the heat transfer and flow behavior of ZA9 semi-solid alloy in solidification process at different temperature, temperature field distribution of the alloy in different process, and metallographic diagram at different temperatures were obtained, and the solidification rate and grain shape characteristic scale at corresponding temperature were calculated. The experimental results show that under the condition of larger temperature difference, the molding speed of grain is faster, thus the alloy has excellent heat transfer performance; After mechanical vibration and mechanical stirring, the dendritic crystal is broken off, grain refines, and the temperature field distribution in the semi-solid alloy tends to be homogeneous, thus improving microstructure and properties of alloy.