镁合金晶粒异质形核的细化方法

Heterogeneous nucleation grain refinement methods for magnesium alloy

总结了目前镁合金晶粒细化技术中广泛应用的异质形核细化方法,并对其细化机理进行论述。边对边匹配(edge-to-edge matching,简称E2EM)模型与第一性原理计算方法均可以判断镁合金的潜在异质形核核心,是近年来研究异质形核晶粒细化的有效方法。向镁合金中添加溶质元素及中间合金等物质已成为现工业生产中广泛适用的细化技术。为了更好地从微观尺度理解晶粒细化机制,基于密度泛函理论(density functional theory,简称DFT)的第一性原理计算方法不仅能够准确提供界面处原子结合情况,还可以定量预测凝固中异质晶核与初生相之间界面能和黏附功等,为晶粒细化剂的发展提供了理论基础,在镁合金晶粒细化中发挥越来越重要的作用。

The methods of heterogeneous nucleation refinement widely used for grain refinement of magnesium alloy and the grain refinement mechanism were summarized.The edge-to-edge matching（E2EM）model and the firstprinciple calculation method can determine the potential heterogeneous nucleation core of magnesium alloy,which are effective methods to study the refinement of heterogeneous nucleation grains in recent years.The addition of solute elements and intermediate alloys to magnesium alloys has become a widely used refinement technique in industrial production.To better understand the microscopic mechanism of the grain refinement,the first-principle calculation based on the density functional theory（DFT）can not only accurately provide the information of the binding of atoms on the interface but also quantitatively predict the heterogeneous nucleation in the alloys during solidification and the interfacial energy and the adhesion work of the interface of the nucleus and the primary phase.It can also provide a theoretical basis for the development of the grain refining agent and play a more and more important role in the grain refinement of magnesium alloy.