【作者】 付长明； 董晨； 屈伸； 袁金才； 田继丰；

【Author】 FU Chang-ming,DONG Chen,QU Shen,YUAN Jin-cai,TIAN Ji-feng (Materials Failure Analysis Center,Shenyang National Laboratory for Materials Science(SYNL),Institute of Metal Research(IMR),Chinese Academy of Sciences(CAS),Shenyang 110016,China)

【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】 某公司生产的汽车发动机悬置支臂安装成车后运行20公里发生断裂,对断口进行宏观观察和扫描电镜观察,分析了材料的化学成分和金相组织。结果表明:断口分为平坦区、细区和粗区三个部分。其中平坦区为疲劳裂纹起始和扩展区,属于疲劳区;细区和粗区为断裂区,粗区的断裂速度比细区更快。因此,支臂断裂属于疲劳破坏。从支臂断件上取样做疲劳模拟实验,再现了实物断口上的平坦区特征,进一步证实了平坦区属于疲劳断裂。更多还原

【Abstract】 The engine suspension arm was broken after mounted to run 20 km.The failure reason was analyzed by chemical composition and microstructural observations with OM and SEM.The results show that the fracture surface can be divided into three zones,including flat area,fine area and rough area.Flat area is the initiation and extension zone of fatigue crack;fine area and rough area are the fracture zones, and the fracture rate in the rough area is faster than that in the fine area.Therefore,the failure of the arm belongs to the fatigue fracture.In order to verify flat area on the fracture surface as fatigue fracture,broken pieces from the 20 km sample were carried out cyclic loading to simulate the fatigue process.The result of fatigue experiment coincided with that of real pieces because of the appearance of flat area of the fracture.Furthermore,it is confirmed that flat area belongs to the fatigue fracture.更多还原