Mg-Al合金晶粒细化研究进展

Developments of Grain Refinement in Mg-Al Based Alloys

对Mg-Al合金晶粒细化的研究进展进行了综述。在理论研究方面,边-边匹配模型(E2EM)成功用于预测镁合金的异质形核颗粒,相互依存理论清晰的表述了镁合金晶粒的形核与长大过程,合金平均晶粒尺寸由无形核区大小和异质形核颗粒平均间距共同决定;在实验研究方面,高纯Mg-Al合金的天然形核机制来源于Al-C相的异质形核作用,而Mg-Al合金中含有Fe和Mn元素时,Al-C相的异质形核作用被破坏,Al-Fe-Mn三元相取代Al-C相起到异质形核作用。对比了Mg-Al合金不同细化方式的优缺点,指出过热处理和C细化方法是目前Mg-Al合金最有效的细化方法,并对今后Mg-Al合金晶粒细化研究的方向进行了展望。

Theoretical developments and recent researches on grain refinement of Mg-Al based alloys were summarized in the present study. In theoretical study, the E2EM model was successfully used in Mg alloy to predict potential grain refinement nucleates. The interdependence theory shows the interdepence between grain growth and nucleant selection. The average grain size is determined both by the size of nucleation-free zone and the average inter-particle spacing. In experimental study, the native grain refinement comes from the Al-C particles in high purity Mg-Al alloys, while containing Fe and Mn in Mg-Al alloys, the grain refinement effect of Al-C particles is inhabited, and instead, the Al-Fe-Mn particles act as the nuclei. The different methods of grain refinement in Mg-Al alloys were compared, and pointed that superheating and carbon-based grain refiners were most effective ways to refine grains. The possible research directions of grain refinement in Mg-Al alloys were also proposed.