多股铜导线过载残留物断面形貌分析

Analysis of fracture surface morphology on overload residues of strand copper wires

利用火灾痕迹物证综合实验台,制备多股铜导线在不同过载电流作用下的残留物,用扫描电子显微镜观察、分析导线的断面形貌。结果表明,随着过载电流的增大,导线断面形貌逐渐由纤维状向礁石状转变,韧窝越来越小,越来越浅;最终断裂区逐渐增大,颈缩现象越来越不明显。因此,利用扫描电子显微镜观察、分析多股铜导线断面的形貌特征,可以鉴别其是否过载以及过载的程度。

The residues of strand copper wires under different overcurrent were prepared with the integrated experimental system for fire trace material evidence.The fracture surface morphology of the wires were observed and analyzed by scanning electron microscope（SEM）.The results indicated that the fracture surface morphology transformed gradually from fibrous shape to rock shape,and the dimple got more and more shallow and small with the increase of overcurrent.The last fracture section became bigger and bigger,and the neck shrink phenomenon became more and more inconspicuous.Therefore,using SEM to observe and analyze the fracture surface of strand copper wire can identify whether the wire is overloaded and the degree of overload.