复杂环境下失效电子元器件的综合检测与原因分析

Comprehensive Detection and Cause Analysis of Failed Electronic Components in Complex Environment

采用金相显微镜、扫描电镜和拉伸试验机等手段,对复杂环境下电子元器件进行了综合检测和失效原因分析。结果表明,失效电子元器件中铜镁导线材料的化学成分符合规范要求,但是部分单线表面局部分布有不同尺寸横向压痕,不符合规范要求。电子元器件中导线整体在弯扭应力作用下,各单线外侧表面承受较大轴向拉应力;单线在拉应力作用下,极易在表面横向压痕处发生应力集中,疲劳裂纹优先从受力较大单线的压痕缺陷处起始,并顺着弯扭应力方向扩展一定距离后斜向剪切瞬断。在实际应用过程中,应该避免导线外表面受到挤压损伤而演变为疲劳裂纹源。

By means of metallographic microscope,scanning electron microscope and tensile testing machine,the electronic components in complex environment were comprehensively tested and the failure causes were analyzed.The results show that the chemical composition of copper magnesium conductor material in failed electronic components meets the specification requirements,but some single wire surfaces are locally distributed with transverse indentation of different sizes,which does not meet the specification requirements.Under the action of bending and torsion stress,the outer surface of each single wire in electronic components bears large axial tensile stress.Under the action of tensile stress,the single line is prone to stress concentration at the transverse indentation on the surface.The fatigue crack preferentially starts from the indentation defect of the single line with large stress,extends for a certain distance along the direction of bending and torsional stress,and then breaks in oblique shear.In the process of practical application,it should be avoided that the outer surface of the conductor is damaged by extrusion and evolves into a fatigue crack source.