In-situ Observation of Mixed Mode Fatigue Crack Growth Behavior in Heat Affected Zone of a Welded Joint
In-situ scanning electron microscope (SEM) observations of fatigue crack growth behavior in heat affected zone (HAZ) of a welded joint were performed with CTS (Compact-Tension-Shear) specimens under mixed-mode loading conditions in vacuum.Results showed that mode I fatigue behavior in the HAZ was influenced by local microstructure anisotropy and the ‘zigzag mode crack profile tended to deviate into the lower strength weld metal.With increasing the mixity of mode I/II loadings,fatigue crack growth rate was decreased with significant crack branching.Shear and branch cracks were competitive along the crack path,and fatigue cracks were often initiated from grain boundary and the interface of lath martensites.The cracks tended to orient themselves into a pure mode I condition.Three existing models were discussed with respect to their capabilities to predict crack direction under various loading conditions.
in-situ SEM fatigue crack growth crack growth path mixed-mode loading heat affected zone
Ming-Liang Zhu De-Qiang Wang Fu-Zhen Xuan Shan-Tung Tu
Key Laboratory of Pressure Systems and Safety,Ministry of Education,East China University of Science and Technology,Shanghai 200237,China
国际会议
北京
英文
1-10
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）