Microstructure and Texture Characterization in Nd:yag Laser Welds of 5A90 Aluminium-Lithium Alloy

摘要

Microstructure and texture characterization in Nd:YAG laser welds of 5A90 Aluminium-Lithium (Al-Li) alloy 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 texture of the welds in 5A90 Al-Li alloy were investigated and compared with the unaffected base metal. It was revealed 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 texture changes for 5A90 Al-Li alloy after laser welding. TEM images indicate that the laser welding has no influence on the dislocation density.