摘要
研究了6N01-T5铝合金搅拌摩擦焊(FSW)和氩弧焊(MIG)接头不同部位的疲劳裂纹扩展性能,并对疲劳断口和接头组织进行了分析.结果表明,对于FSW和MIG焊接头,其裂纹扩展速率从高到低的部位依次为焊缝(核)区、热影响区和母材.裂纹在FSW和MIG焊接头相同区域的扩展速率无明显差别,然而裂纹在FSW接头细晶组织中开始扩展所需的门槛值ΔK要比对应的MIG焊接头高,总体上其裂纹在FSW焊核区的抗疲劳裂纹扩展性能要优于对应的MIG焊缝区.裂纹在FSW和MIG焊接头焊核(缝)区扩展的疲劳断口表现为脆性断裂,而在热影响区则以规则和光滑的疲劳条纹形式扩展.
Fatigue crack propagation( FCP) behavior at different locations of friction stir welded( FSW) and metal inertgas welded( MIG) A6N01 joints were studied. The fatigue fractures and microstructures of the joints were analyzed. For FSW and MIG joints,the fatigue crack propagation rate( FCPR) in nugget( weld) zone was the highest,while the FCPR in heat-affected zone( HAZ) was lower than that in the nugget( weld)zone. The base metal had the highest fatigue crack propagation resistance. The FCPR had no significant difference when crack propagated in the same regions of FSW and MIG joints. However,the fatigue crack growth threshold( ΔKth) of crack propagating in the nugget zone of FSW joint was higher than that of MIG joint,in other words,the resistance to fatigue crack propagation in the nugget zone of FSW joint was superior to that of MIG joint. The fracture surface of fatigue crack propagating in the nugget( weld) zone of FSW and MIG joints revealed brittle fracture,while that in heat-affected zone was mainly plastic fatigue striation.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2015年第9期9-12,38,共5页
Transactions of The China Welding Institution
基金
国家自然科学基金资助项目(51375259)
关键词
搅拌摩擦焊
疲劳裂纹扩展
微观组织
6N01铝合金
friction stir welding
fatigue crack propagation
microstructure
6N01 aluminum alloy
