AZ31B镁合金焊接接头的疲劳裂纹扩展行为(英文)  

Fatigue Crack Propagation Behavior of as-Extruded AZ31B Mg Alloy Welded Joint

作　　者：张红霞[1] 裴飞飞[1] 闫志峰[1] 王文先[1] 梁培阳[1] 李娟[1] 卫英慧[1] 

机构地区：[1]太原理工大学,山西太原030024

出　　处：《稀有金属材料与工程》2012年第6期967-972,共6页Rare Metal Materials and Engineering

基　　金：NSFC (50675148, 51175364)

摘　　要：对AZ31B 镁合金焊接接头和热影响区的疲劳裂纹扩展行为进行研究,分析了焊接接头[L-T(W)]和热影响区的紧凑拉伸试验[C(T)],其中热影响区的C(T)试验包括焊缝平行于挤压方向[T-L(H)] 和垂直于挤压方向 [L-T(H)]两种。结果表明:对于L-T(W) 试样,裂纹沿挤压方向扩展,裂纹扩展经历先快后慢的扩展过程;T-L(H) 试样裂纹平行于缺口方向扩展,L-T(H)试样裂纹为平行于缺口方向和与缺口成一定角度两种扩展方向,裂纹扩展经历先慢后快的扩展过程。裂纹尖端扩展为穿晶和沿晶的混合模式,疲劳断口为准解理特征的脆性断口。The fatigue crack propagation behavior of as-extruded AZ31B magnesium alloy welded joint and heat affected zone have been studied. Compact tensions [C（T）] of welded joint [L-T（W）] and heat affected zone（welded joint is parallel [T-L（H）] and vertical [L-T（H）] to the extruded direction） were researched. Results indicate that the crack propagation direction is parallel to the extrusion direction for L-T（W）; fatigue crack propagation rate is a rapid-slow process. T-L（H） is parallel to the notch direction and L-T（H） can be divided into two states （i.e., parallel to or angularly deflected towards the notch direction）; crack propagation rate initially goes through a rapid course before it slows down. The fracture modes of crack tip remain a mixed-mode of transgranular and intergranular fractures. The fatigue fracture consists of quasi-cleavage and is a brittle fracture.

关 键 词：AZ31B镁合金 焊接接头 裂纹扩展速率 脆性断口 

分 类 号：TG407[金属学及工艺—焊接]