AZ91镁合金的凝固冷却速度与二次枝晶间距的定量关系研究

Quantitative Research on Relationship Between Secondary Dendrite Arm Spacing and Solidification Cooling Rate of AZ91 Magnesium Alloy

通过设计制作一套可获得不同凝固冷却速度的镁合金熔炼与浇注装置,采用多通道连续温度记录仪,获得了对应不同凝固冷却速度下的AZ91镁合金试样。用定量金相分析之截线法测定了各个试样的二次枝晶间距,并对不同凝固冷却速度下的组织特征做了简要分析。用数学回归的方法得到了AZ91镁合金的凝固冷却速度与二次枝晶间距的定量关系式。

AZ91 magnesium alloy specimens with various solidification cooling rates were obtained by designing a melting and pouring equipment which could get different solidification cooling rate and by recording temperatures with multichannel continuous temperature recorder. Secondary dendrite arm spacing（DAS） was measured by transvesal method of quantitative metallographic analysis, and the microstructure characters under different solidification cooling rates were analyzed briefly. The quantitative relationship between secondary dendrite arm spacing and solidification cooling rate of AZ91 was obtained by regressive analysis.