Single-shot femtosecond laser processing of Al-alloy surface: An interplay between Mbar shock waves, enhanced microhardness, residual stresses, and chemical modification

Abstract

Ambient-air single-shot ablative femtosecond laser surface processing of an advanced Al-alloy AA5083 was characterized by non-contact broadband ultrasonics, scanning electron microscopy with energy-dispersive x-ray spectroscopy, x-ray diffraction, and Vickers microhardness tests. The characterization indicates that the generated Mbar-level shock waves induce not only a strong structural modification of the processed micron-thick surface layer with sub-GPa-level residual compressive and tensile stresses, raising its microhardness by almost 45%, but also significant depth-dependent chemical modification within the layer.