Laser material interaction parameter: New tool for developing property diagrams for welds

Detailed processing-property correlation studies have been attempted on laser beam welded AA 5024 (Al-Mg-Sc) alloys. These alloys are mostly used for integrally stiffened panels for aerospace applications. Different combinations of laser power, weld speed, beam diameter, and beam shape were chosen, and an optimized yield stress and uniform elongation map has been obtained. A comparative assessment of weld quality was done for the solid-state laser and the CO2 laser with two heat transfer modes, i.e., deep penetration (keyhole) and partial penetration (conduction) modes used for various aforementioned parameters. The weld parameters are ranked thereafter according to their merits and demerits encountered in this work. It has been seen that flexibility in terms of power, speed, and energy of a solid-state laser is more compared to the CO2 laser. Fundamental laser material interaction parameters have been studied, and an optimization strategy was formulated based on specific point energy of beam material interaction. The weld pool geometry has also been studied and correlated with interaction parameters. Weld size, shape, geometry, and evidence of solidification cracking have been studied from weld cross section macrographs. Variations of weld yield strength and elongation with welding energy input have been investigated thoroughly. Based on the above examinations, exaction of the optimal processing window is achieved.