层状异构Mg-3Gd合金的微观组织和力学性能

Microstructure and Mechanical Properties of Layered Heterostructured Mg-3Gd Alloy

以Mg-3Gd(质量分数,%)合金为研究对象,采用累积叠轧和退火工艺制备了由层厚不均匀的回复组织层和再结晶组织层交替组成的层状异构样品。拉伸实验结果表明,这种层状异构样品可以在同等拉伸塑性的条件下获得比均匀再结晶结构更高的强度,并表现出成形加工所需的连续流变行为。回复层和再结晶层之间的协调变形激发了锥面<c+a>滑移在界面附近的开动,增强了位错增殖和累积,提高了加工硬化率和塑性。

As the lightest structural metallic materials,Mg alloys have immense development potential in the automotive,aerospace,medical,and electronic industries.However,the low strength and the poor ductility of Mg alloys limit their engineering applications.Recent investigations have shown that heterostructured Mg alloys exhibit significantly improved strength and ductility.This work applies accumulative roll-bonding and subsequent annealing to a Mg-3Gd alloy to produce layered heterostructures composed of alternating recovered and recrystallized layers of varying thicknesses.These heterostructures exhibit higher strength than homogeneous grain structures at a similar tensile ductility.They also show a continuous flow behavior desired for metal forming.A high density of the<c+a>dislocations is activated at the interfaces between the layers to accommodate the deformation incompatibility,which contributes to dislocation multiplications and accumulations and enhances work hardening rate and ductility.