6063铝合金板材锯齿形屈服行为的研究(续)

Study on Serrated Yielding in 6063 Aluminium Alloy Plate(Sheet)

再加载时间体现为应力上升的过程。位错群在障碍处被钉扎、等待再次被激活的时间则被定义为等待时间tw。在等待过程中由于动态应变时效，要克服额外的钉扎所需的应力增加。等待时间越长，再加载时间也越长[9]。从宏观角度看，随着变形速度的增大，应力应变曲线锯齿阶段的周期就越小，相应的再加载时间也就越小，且再加载时间的数目也随之减少。

Through a systematic statistical analysis of the serrated yielding on 6063 aluminium alloy, this paper studied the law of the stress drop amplitude, the reloading time and the drop duration changing with the deformation speed, and discussed the influence of serrated yielding effect on mechanical properties. The results show that the stress drop amplitude, reloading time and its number, drop duration and its number are decreased when the deformation speed reduce; The serrated yielding effect is weakest and the mechanical properties are best when the deformation speed is 2mm/min.