采用模拟试验制备了铜导线火烧熔痕、一次短路熔痕和二次短路熔痕，观察了这些熔痕的微观形貌并总结了其微观特征。结果表明：火烧熔痕断口基本没有孔洞；在高温作用前后，一次短路熔痕的微观特征相似，断口上存在均匀、细密的孔洞，呈卵形花样；二次短路熔痕断口上的孔洞大小不一，呈蜂窝状花样。

The fire melted mark, primary short circuited melted mark and secondary short circuited melted mark of the copper wire were prepared by simulation experiments. The micromorphology of these marks were observed and the microscopic characteristics was summarized. The results show that no holes existed at fracture of the fire melted mark. The microscopic characteristics of the primary short circuited melted mark before and after being treated at high temperature was the same; uniform and fine holes existed at the fracture and the fracture presented an oval pattern. The holes at fracture of the secondary short circuited melted mark varied in size and the fracture presented a honeycomb pattern.