Microstructure and Properties of Laser Welded Aluminum-lithium Alloy 5A90 in Lapped Joints

The dual-spot laser welding technics for 3.0 and 4.0 mm thick 5A90 aluminum-lithium alloy was researched. Microstructure and properties of lapped joints was also analyzed. The results showed that reasonable adjusting the laser power and welding velocity could enhance the stability and improve the weld shape during dual-spot laser welding.There was the equiaxed grain-refining zone between the partially melted zone of base metal and columnar crystal in weld. Microstructure in weld center was equiaxed dendrite, the grain size was refined and uniform with the decrease of laser power and the increase of welding velocity.