Molten Pool Behavior,Microstructure and Mechanical Property in VPTIG Full Penetration Welding of Medium-thick 2219 Aluminum Alloy
Focusing on the double-pulsed variable polarity TIG(DP-VPTIG)full penetration welding process of 2219-T87 aluminum alloy,the heat and mass transfer behavior of the molten pool were investigated by using high-speed image acquisition and multi-physics numerical simulation technology.The impact mechanisms of double-pulsed current and square wave variable polarity current on molten pool were revealed.The influence of DP-VPTIG arc on joint microstructure and mechanical properties was also explored.Obtained results show that the double-pulsed current effectively stimulates the formation of keyhole in molten pool.Square wave variable polarity current can make a contribution to a stable welding process.Moreover,DP-VPTIG enables efficient,high-quality full penetration welding for medium-thick aluminum plates.In comparison to conventional VPTIG,DP-VPTIG joints exhibit more refined weld microstructures,with enhancements in tensile strength,yield strength,and elongation by 8％,17％,and 22％,respectively.
medium-thick aluminum alloyVPTIG weldingnumerical simulationmicrostructure and mechanical property
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