Analysis of the Formation Process of AA 2219-T87 Friction Pull Plug Welding
Friction pull plug welding(Friction pull plug welding,FPPW)is a high efficient solid-state repair welding technology widely used in the aerospace field.In this study,12mm thick aluminum alloy plates were selected to carry out FPPW trails.The method of emergency stop at different welding stages was applied to explore the forming process.The full-process welding was used to analyze microstructure and properties.According to the change of pull force,FPPW process could be divided into pre-friction stage,loading stage,constant force welding stage and forging stage.The results of emergency stop at different welding stages showed that in the early stage of welding,the sliding friction was the main friction mode and preheated the interface.The heat increased as the welding process progresses,and local bonding occurred at the interface.In the later stage of welding,adhesive friction played a dominant role so that the interface bonding condition emerged and then bonded well during the forging stage.The results of full-process welding showed that when the welding tensile force was 50 kN,a brittle second-phase continuously distribute on the bonding interface which lowered the bonding strength.As the welding tensile force was increased to 60 kN,the strength increased with the decreasing of the second phase in the bonding interface.However,when the welding tensile force rose to 70 kN,necking occurred at the joint and continuous tiny pores appeared on the bonding interface,resulting in a significant decrease in strength.These research results can provide a good reference for medium-thick plate FPPW forming.
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维普
