1. The dynamic change process of the crack coppicing and extending on annealed Q & P steel was in-situ observed by SEM, and the micro-crack characteristic was studied. 采用扫描电镜（SEM）原位拉伸观察了Q&P钢退火组织断裂过程中裂纹萌生和扩展的动态变化过程，并对其微观断裂特征进行了研究。