It was found that many dislocations were emitted from the crack tip during the early stage of crack propagation and were driven out of the crack tip area , and them piled up inversely . a closed dislocation free zone ( dfz ) was formed between the crack tip and the pile - up dislocations . keeping displacement constant , the dislocations were still emitted from the crack tip for a while 本文首先系統(tǒng)地研究了工業(yè)純金屬( fe , al , ti和mg )斷裂的微觀過程,發(fā)現(xiàn)所研究的工業(yè)純金屬斷裂過程裂尖均首先發(fā)射位錯,并離開裂尖向前運動、在裂尖留下無位錯區(qū),位錯反塞積在五位錯區(qū)的端部,反塞積位錯群一般呈封閉狀包圍無位錯區(qū)。