Void damage evolution of LF6 aluminum alloy welded joints under external load and thermal cycling conditions  

作　　者：米国发 赵大为 董翠粉 牛济泰 金成 

机构地区：[1]School of Materials Science and Engineering,Henan Polytechnic University [2]School of Materials Science and Engineering,Harbin Institute of Technology [3]School of Materials Science and Engineering,Dalian Jiaotong University

出　　处：《Transactions of Nonferrous Metals Society of China》2010年第10期1968-1973,共6页中国有色金属学报（英文版）

基　　金：Project(90205035) supported by the National Natural Science Foundation of China

摘　　要：Based on the simulated aerospace thermal cycling tests,the effect of thermal cycle on the void damage evolution mechanism of LF6 aluminum alloy welded joint was investigated.The results show that micro-voids form around the second phase particles under the thermal cycling tests.The thermal stress coupled with external stress leads to dislocations pile-up around the particles,and when the dislocation density reaches a certain degree,the stress concentration will exceed the bonding strength at the interface between particles and matrix,resulting in the formation of micro-cracks.The numerical simulation is successfully implemented with the finite element to describe the void damage evolution of the welded joint under thermal cycling conditions.Based on the simulated aerospace thermal cycling tests,the effect of thermal cycle on the void damage evolution mechanism of LF6 aluminum alloy welded joint was investigated.The results show that micro-voids form around the second phase particles under the thermal cycling tests.The thermal stress coupled with external stress leads to dislocations pile-up around the particles,and when the dislocation density reaches a certain degree,the stress concentration will exceed the bonding strength at the interface between particles and matrix,resulting in the formation of micro-cracks.The numerical simulation is successfully implemented with the finite element to describe the void damage evolution of the welded joint under thermal cycling conditions.

关 键 词：aluminum alloy welded joint thermal stress numerical simulation micro-void 

分 类 号：TG407[金属学及工艺—焊接] O346.5[理学—固体力学]