【作者】 付长明； 董晨； 屈伸； 田继丰； 苏会和； 张哲峰；

【Author】 FU Chang-ming;DONG Chen;QU Shen;TIAN Ji-feng;SU Hui-he;ZHANG Zhe-feng;Materials Failure Analysis Center,Shenyang National Laboratory for Materials Science(SYNL),Institute of Metal Research(IMR),Chinese Academy of Sciences(CAS);

【机构】 中国科学院金属研究所沈阳材料科学国家(联合)实验室材料失效分析中心；

【摘要】 某公司在对若干印刷电路板做扫频振动试验后,检查发现某些印刷电路板某器件引脚出现不同程度的开裂。通过对引脚断口的宏观检验、体视镜放大宏观检验、扫描电镜检验和金相检验,确定了引脚断裂性质和原因。结果表明:引脚断裂属于疲劳断裂,导致引脚疲劳断裂的主要原因是扫频振动试验提供了促使引脚萌生疲劳裂纹并进行扩展的较大交变应力,在引脚横截面最小的部位引起开裂甚至断裂。建议在其引脚处涂抹硅胶,以减少引脚的变形量,大幅度降低引脚所受的工作应力,从而提高引脚抗疲劳断裂的能力。更多还原

【Abstract】 A number of chip pins on the printed circuit boards fractured after a vibration test.By macroscopic examination,stereoscope zoom macroscopic examination,scanning electron microscope inspection and metallographic examination of the fractured chip pins,the nature and causes of the fault were found out The results show that the fracture mode of the pins was fatigue fracture.The main reason for the fracture of the chip pins was large alternating stress that caused cracking in the smallest parts of the pin cross-section and even rupture by the vibration test.Smearing silicone around the pins was recommenled in order to reduce the amount of deformation and suffered stress of the pins,thereby enhancing the ability to the anti-fatigue fracture of the pins.更多还原