2219铝合金拉拔式摩擦塞补焊接头界面缺陷研究

Study on Interfacial Defects of 2219 Aluminum Alloy Friction Pull Plug Welding

本文研究了2219铝合金拉拔式摩擦塞补焊(Friction Pull Plug Weld,FPPW)接头界面组织形貌,结合仿真探讨了界面缺陷的形成原因,并分析了界面缺陷对接头拉伸性能的影响。结果表明,FPPW接头界面缺陷可分为弱结合与未焊合。弱结合以界面产生弯曲,且界面间隙中存在氧化物与富Cu相为特征;未焊合缺陷以存在平直界面为特征。FPPW接头界面缺陷由界面温度及应变分布不均所致。界面温度及应变分布不均表明塞孔侧壁热塑性金属流动性差异大,材料流动不充分,未能填充界面微区间隙,从而造成界面缺陷。当接头承受拉应力时,界面未焊合削减了接头有效承载面积,而弱结合处的析出相易引起应力集中,导致接头拉伸性能下降。

In this paper,the interfacial morphology of 2219 aluminum alloy FPPW joint is studied,the causes ofinterfacial defects are discussed by simulation,and the effects of interfacial defects on tensile properties of the joint areanalyzed.The results show that the interfacial defects of FPPW joints can be divided into weak bonding and unweldedbonding.The weak bonding is characterized by the bending of the interface and the presence of oxide and Cu-rich phasein the interfacial gap.Unwelded defects are characterized by flat interface.The interfacial defects of FPPW joints arecaused by the uneven distribution of interface temperature and strain.The uneven distribution of temperature and strainat the interface indicates that the fluidity of the thermoplastic metal on the side wall of base matal is very different,andthe material flow is insufficient,which fails to fill the interfacial microgap,resulting in interfacial defects.When the jointis subjected to tensile stress,the unwelded interface reduces the effective bearing area of the joint,and the precipitatedphase at the weak joint is easy to cause stress concentration,resulting in the decline of the tensile property of the joint.