AZ91D镁合金的冷却凝固特性研究

Research on Characteristics of Cooling and Solidification of AZ91D Mg-alloy

采用DSC对AZ91D镁合金的冷却凝固特性进行了研究。研究发现,AZ91D镁合金的液相线温度为595℃,固相线温度为470℃,液、固相线温度差为125℃,属于宽结晶温度范围低熔点合金。该合金的平均自由线收缩率为1.572%,冷却凝固时倾向于体积凝固方式,容易形成粗大的离异共晶组织。

The characteristics of cooling and solidification of AZ91D magnesium alloy were studied by using DSC. The results indicate that AZ91D magnesium alloy liquidus temperature is about 595℃ and solidus temperature is about 470℃, so the difference between solid and liquid temperature is 125℃, which implies that AZ91D magnesium alloy belongs to a type of wide crystallization temperature range and low-melting-point alloy. The average free line contraction rate of AZ91D magnesium alloy is 1.572%, its solidification mode is inclined to be paste-solidification, which is prone to form coarse divorced eutectic structure in the casting.