Mechanical and functional properties of ultra-thin Mg foils

Abstract

Wide and thin Mg foils with thicknesses between 35 μm and 400 μm without any edge cracks are successfully produced by using commercial grade Mg (99.9% purity), in this study. Control of the initial microstructure in the billet (before rolling) is effective and essential from a processing viewpoint. All of the produced rolled foils have similar microstructures, i.e., grain sizes of approximately 10 μm, and a basal texture, regardless of the foil thickness. The results obtained from hardness (indentation) and tensile tests demonstrate the effect of foil thickness on mechanical properties. Hardness is independent of the indentation plane and foil thickness; on the contrary, the decrease in tensile strength is observed at the critical value of t/d, where t is the foil thickness and d is the grain size, owing to the lack of grain boundaries. This trend is the same as that shown by other thin foils of conventional metallic materials. In addition to the foil thickness effect, these rolled Mg foils exhibit good damping property in association with their crystal structure. This provides the possibility for Mg foils to be employed in electric devices and other applications.