Fatigue crack growth of titanium alloy joints by electron beam welding  

作　　者：Hong-Yu Qi Hao Shi Shao-Lin Li Xiao-Guang Yang 

机构地区：[1]School of Jet Propulsion, Beijing University of Aeronautics and Astronautics

出　　处：《Rare Metals》2014年第5期516-521,共6页稀有金属（英文版）

基　　金：financially supported by the Hi-Tech Research and Development Program (863) of China (No. 2012AA052102);Program of International Science and Technology Cooperation of China (No. 2013DFA61590);the National Natural Science Foundation of China (No. 51275023)

摘　　要：Electron beam welding（EBW） has been widely used in the manufacture of titanium alloy welded blisk for aircraft engines. Based on fatigue crack growth tests on titanium alloy electron beam welding（EBW） joints, mechanism of fracture was investigated under scanning electron microscope（SEM）. The results show that fatigue crack growth rate increases as the experimental load increases under the same stress ratio and stress intensity factor range. At the beginning of crack growth, the extension mechanism of fatigue crack is the typical mechanism of cleavage fracture. In the steady extention stage, crack extends along the weld seam firstly.Then, crack growth direction changes to extend along the base metal. The extension mechanism of fatigue crack in the weld seam is the main mechanism of cleavage fracture and the extension mechanism of fatigue crack in the base metal is the main extension mechanism of fatigue band. In the instantaneous fracture stage, the extension mechanism of fatigue crack is the typical dimple-type static fracture mechanism.Crack growth was simulated by conventional finite element method and extended finite element method.Electron beam welding（EBW） has been widely used in the manufacture of titanium alloy welded blisk for aircraft engines. Based on fatigue crack growth tests on titanium alloy electron beam welding（EBW） joints, mechanism of fracture was investigated under scanning electron microscope（SEM）. The results show that fatigue crack growth rate increases as the experimental load increases under the same stress ratio and stress intensity factor range. At the beginning of crack growth, the extension mechanism of fatigue crack is the typical mechanism of cleavage fracture. In the steady extention stage, crack extends along the weld seam firstly.Then, crack growth direction changes to extend along the base metal. The extension mechanism of fatigue crack in the weld seam is the main mechanism of cleavage fracture and the extension mechanism of fatigue crack in the base metal is the main extension mechanism of fatigue band. In the instantaneous fracture stage, the extension mechanism of fatigue crack is the typical dimple-type static fracture mechanism.Crack growth was simulated by conventional finite element method and extended finite element method.

关 键 词：MICROFORMING Ti–6Al–4V alloy Electron beam welding Fatigue crack growth Fracture analysis 

分 类 号：TG407[金属学及工艺—焊接] TG457.1