514 北京科技大学学报 2004年第5期 (a)e=1s,e-0.20 (b)e=1s,e=0.36 (c)e=1s,e=0.51 40m de=10s',8=0.20 (e)e=10s,e0.36 (06=10s,8=0.51 图2低碳钢在760℃，真应变为0.20,0.36,0.51，形变速率为1s'和10s形变时的SEM形貌 Fig.2 SEM micrographs of the low carbon steel after deformation at 760C,strain rates of 1sand 10sand true strains of 0.20,0.36,0.51 respectively (a)e=1s',e=0.70 (b)e=1s1,e=0.92 (C)e=1s,e=1.11 20um (de=10s,e-=0.70 (e)e=10s,8=0.92 (0e=10s1,6=111 图3低碳钢在760℃，真应变为0.70,0.92,111，形变速率为1s和10s形变时的SEM形貌 Fig.3 SEM mierographs of the low carbon steel after deformation at 760C,strain rates of 1s"and 10sand true strains of 0.70,0.92,1.11 respectively (ae=1s,e=1.27 b)8=181,e=1.40 (c)e=1s',ε=1.61 20 um (d)6=10s,e=127 (e)e=10s,8=1.40 (①8=10s,8=1.61 图4低碳钢在760℃，真应变为127,1,40,1.61形变速率为1s和10s形变时的SEM形貌 Fig.4 SEM micrographs of the low carbon steel after deformation at 760C,strain rates of 1sand 10sand true strains of 1.27,1.40,1.61 respectively