Relationship between the weld pool convection and metallurgical and mechanical properties in hybrid welding for butt joint of 10-mm-thick aluminum alloy plate

The ALHW and LAHW processes are applied to join 5083 aluminum alloy with thickness 10 mm; the differences of weld pool convection is studied, and the relationship between the weld pool convection and microstructural characterization of aluminum alloy in ALHW and LAHW processes are analyzed. The result shows that an inward flow pattern, furious mingling, and stirring effects in LAHW process will contribute to a better weld bead with lower porosity level. The shorter escaping route of the bubble. more difficult bubble captured, and better stability of the keyhole are the three effective factors for eliminating of porosity. In LAHW process, the grain size is larger, but the LAHW joints have higher tensile strength, which is greatly influenced by porosity and second-phase particles. Compared with ALHW process, the LAHW process is beneficial to get the less weld defects, better bead formation, and higher tensile strength, which is conducive to successfully weld aluminum alloy thick plates potentially.