体心立方金属韧脆转变机制研究进展

韩卫忠, 卢岩, 张雨衡

Mechanism of Ductile-to-Brittle Transition in Body-Centered-Cubic Metals：A Brief Review

HAN Weizhong, LU Yan, ZHANG Yuheng

图6 螺/刃位错相对运动速率控制韧脆转变的物理机制[16]

Fig.6 Mechanism of the relative mobility of the screw versus edge dislocations controls the DBT in metals[16] (a) dislocation relative mobility determines the efficiency of dislocation source (TC—critical temperature, ve—edge dislocation velocity, αDBT—the α value at DBTT, α—velocity ratio of screw dislocation and edge dislocation, t0—time before dislocation bow out, t1—time after dislocation bow out) (b) relative mobility of screw versus edge dislocations with temperature for Cr, Al, W, and Fe (c) bowing out an edge dislocation to form a half loop (r—dislocation source radius) (d) bowing out the half loop if vs = 0 (x—distance moved by edge dislocation) (e) bowing out the half loop with side glide (vs > 0) (y—distance moved by screw dislocation, Aedge—region swept by the edge dislocation, Ascrew—region swept by the screw dislocation)