Dwell and Normal Cyclic Fatigue Behaviours of Ti60 Alloy  

作　　者：Lina Yang Jianrong Liu Jun Tan Zhiyong Chen Qingjiang Wang Rui Yang 

机构地区：[1]Institute of Metal Research,Chinese Academy of Sciences

出　　处：《Journal of Materials Science & Technology》2014年第7期706-709,共4页材料科学技术（英文版）

摘　　要：An experimental study of dwell and normal cyclic fatigue behaviours was carried out using specimens from a Ti60 forging with a bimodal microstructure. Apparent decrease in the fatigue life was found under dwell fatigue condition as compared to that under normal cyclic condition. Strain produced in each cycle in dwell fatigued specimens was observed larger than that in its normal cyclic-fatigued counterparts. Interior crack initiation was found in most dwell fatigued specimens as compared to the subsurface crack initiation under normal cyclic fatigue condition. Flat and bright facets were found at crack initiation sites in both cases. The facet density is higher in dwell condition, which is consistent with the crystal orientation and Schmid factors analysis of α grains around secondary cracks using electron back-scattered diffraction （EBSD） methods. Dwell loading favours cleavage in α grains with their basal plane normals aligned no more than 15° to the loading axis, which may account for its lower fatigue life according to the present study.An experimental study of dwell and normal cyclic fatigue behaviours was carried out using specimens from a Ti60 forging with a bimodal microstructure. Apparent decrease in the fatigue life was found under dwell fatigue condition as compared to that under normal cyclic condition. Strain produced in each cycle in dwell fatigued specimens was observed larger than that in its normal cyclic-fatigued counterparts. Interior crack initiation was found in most dwell fatigued specimens as compared to the subsurface crack initiation under normal cyclic fatigue condition. Flat and bright facets were found at crack initiation sites in both cases. The facet density is higher in dwell condition, which is consistent with the crystal orientation and Schmid factors analysis of α grains around secondary cracks using electron back-scattered diffraction （EBSD） methods. Dwell loading favours cleavage in α grains with their basal plane normals aligned no more than 15° to the loading axis, which may account for its lower fatigue life according to the present study.

关 键 词：Ti60 alloy Dwell fatigue Quasi-cleavage facet Electron back-scattered diffraction （EBSD） Strain accumulation 

分 类 号：TG146.23[一般工业技术—材料科学与工程]