Laser Welding of 1420 Aluminium-Lithium Alloys Under the Keyhole Regime
L. Zhuang, Q-S. Meng and L. Chen
In this work samples of 1420 Al-Li alloy sheets have been welded under keyhole regime using a Nd:YAG laser beam. The influence of welding parameters on the size and property of beads-on-plate has been studied. In addition to measuring the depth and width of the weld beads, their mechanical properties and microstructure have been analysed using optical microscope, microhardness testing machine, universal tensile test machine and bending test machine. The results show that the shape of the formed welds changes from nail-head to nearly X-shape with the increase in Nd:YAG laser beam-induced heat input. The equiaxed dendritic grains are formed in the weld, which can reduce the solidification cracking susceptibility. The mechanical properties present a certain degree of degradation due to the presence of porosity.
Keywords: Nd:YAG laser, aluminium-lithium (Al-Li) alloy, laser welding, laser power, beads-on-plate, mechanical properties, microstructure, equiaxed dendritic grain