超塑性变形的三维晶粒重排研究

A Study on 3D Grain Rearrangement in Superplastic Deformation

在总结超塑变形二维晶粒重排模型基础上，研究了超塑变形三维晶粒重排。金相观察表明：１号铝锂合金板状试样宽度方向边层微细晶粒填入中心层大晶粒在拉伸方向产生的空洞而实现晶粒重排。通过扫描电镜观察了晶粒涌出及２号铝锂合金中大Ａｌ３Ｚｒ相在变形时的转动情况。研究表明，微细晶粒是通过晶粒转动填入空洞的，该过程是一个能量降低的过程。宽度方向微细晶粒的运动解释了超塑变形的试样宽度尺寸的减小及试样板边缘局部颈缩迁移的现象。

n the basis of summarizing the modles of 2D grain rearrangement in superplastic deformation, 3D grain rearrangement in superplastic deformation has been investigated.Metallographic observations show that fine marginal lay'Cr grains at latitudinal direction ofplate specimens of 1#(8090)Al-Li alloy filled in the cavities created at tension direction oflarge central layer grains, and completed grain rearrangement. Grain emergence and rotation of large Al,Zr phase in Al-Li-Zr alloy deformed were observed With SEM.The results show that fine grains fill 'in f cavities by grain rotation, which is a process of energy decrease. Thephenomena of decrease in the latitudinal size of specimen and migration of local necking atthe specimen margin in the superplastic deformation ean be explained by the motion of finegrains at latitudinal direction.