7B52-T6叠层铝合金焊接接头组织及疲劳损伤行为  

Microstructure and fatigue damage behavior of 7B52-T6 laminated aluminum alloy welded joint

作　　者：张龙 陈东高[1] 张迎迎[1] 戴宇[1] 马良超 王大锋 郭庆虎 何逸凡 ZHANG Long;CHEN Donggao;ZHANG Yingying;DAI Yu;MA Liangchao;WANG Dafeng;GUO Qinghu;HE Yifan(Ningbo Branch of Chinese Academy of Ordnance Science,Ningbo 315103,China)

机构地区：[1]中国兵器科学研究院宁波分院,浙江宁波315103

出　　处：《兵器材料科学与工程》2021年第2期126-130,共5页Ordnance Material Science and Engineering

摘　　要：用熔化极气体保护焊获得7B52-T6叠层铝合金焊接接头,研究接头的力学性能、显微组织、疲劳损伤行为。结果表明:接头各区由于成分和经历热循环不同,组织、性能存在差异,热影响区发生再结晶和不完全结晶,熔合区有部分细晶区,焊缝中心为等轴晶组织。接头抗拉强度为246 MPa,试样断裂于焊缝区,接头显微硬度分布不均匀,从焊缝中心到母材,显微硬度整体上升,热影响区硬度波动大。接头S-N曲线为σ=533.655-66.247lg N,中值疲劳强度为116 MPa,疲劳裂纹起源于接头表面气孔和距表面0.1 mm的内部气孔处,疲劳扩展区平坦,瞬断区的断裂方式为准解理断裂。The mechanical properties,microstructure and fatigue damage behavior of 7 B52-T6 laminated aluminum alloy welded joint prepared by melt inert-gas(MIG) welding were studied.The results show that due to the different composition and thermal cycle process,the microstructure and properties of the joint are different.Recrystallization and incomplete crystallization occur in the heat affected zone.There are some fine-grained areas in the fusion zone,and equiaxed grain structure is found in the weld center.The tensile strength of joint is 246 MPa,which is fractured at the weld.The microhardness distribution of joint is uneven.From the center of the weld to the base metal,the microhardness almost maintains an upward trand,and the hardness in the HAZ fluctuates greatly.The S-N curve of joint is σ=533.655-66.2471 gN,and the median fatigue strength is 116 MPa.The fatigue cracks originate from the pores on the surface of joint and the internal pores 0.1 mm away from the surface.The fatigue propagation zone is flat,and the fracture mode of the instantaneous fracture zone is quasi-cleavage fracture.

关 键 词：7B52-T6叠层铝合金 显微组织 显微硬度 S-N曲线 疲劳损伤 

分 类 号：TG457.14[金属学及工艺—焊接]