Microstructure and Texture Characterization in Nd:YAG Laser Welds of 5A90 Aluminum-Lithium Alloys

Microstructure and texture characterization in Nd:YAG laser welds of 5A90 Aluminum-Lithium (Al-Li) alloys were studied by means of optical microscope (OM),electron back scattered diffraction (EBSD) and transmission electron microscope (TEM).The solidification structure,misorientation angle,dislocation density and microtexture of the welds in 5A90 Al-Li alloys were investigated and compared with the unaffected base metal.The results show that microstructure and texture changes of the 5A90 Al-Li alloy after laser welding.The solidification structure results show that a zone of equiaxed grains (EQZ) along the fusion boundary is formed and the weld metal exhibits entirely equiaxed dendritic grains for 5A90 Al-Li alloy.EBSD study clearly shows the high angle boundaries (>15°) and microtexture changes for 5A90 Al-Li alloy after laser welding.TEM images indicate that the laser welding has no influence on the dislocation density.