Crystallographic features and microstructure evolution of sandwich warm laser polishing: The case of aluminum foil

Abstract

To obtain high-performance metal foil (the case of aluminum foil) with an ultra-smooth surface and deeply study its polishing mechanism, sandwich warm laser polishing (SWLP) is proposed in this study as a generic polishing approach for metal foils. Investigations of the surface roughness and micro-morphology of aluminum foils polished using SWLP technology revealed that the surface roughness was reduced by 97.5%. However, the inadequate understanding of the polishing and strengthening mechanism may limit the practical application of such technology. Therefore, the crystallographic features and microstructure evolution of the aluminum foil before and after SLP/SWLP were analyzed using transmission electron microscopy (TEM), electron backscatter diffraction (EBSD), and molecular dynamics (MD) simulations, and the mechanism for the reduction in roughness and improvement in tensile properties of the aluminum foil caused by SWLP and the fundamental difference between SLP and SWLP were determined, even the ultrafast dynamical process as small as nanoscale was observed by MD simulation. The nanoscale ultrafast dynamic process, crystallographic features, microstructure evolution, and the fundamental difference between SLP and SWLP revealed in this study are of great significance for understanding the polishing/materials modification mechanism of the aluminum foil, and for the development of future laser polishing technology.