Elasticity Study of Nanostructured Al and Al-Si(Cu) Films

Abstract

In order to get an insight into the elastic property of nanostructured fcc metal films, the Young’s modulus, E_f, and the internal friction, Q^-1_f, in Al-Si(Cu)_sp and Al_sp films prepared by rf-sputtering and those in Al-Si(Cu)_ve and Al_ve films by vacuum evaporation were studied for the thickness, d, range of 4 to 300 nm, where the mean grain size was below 40 nm. A decrease in E_f and an increase in Q^-1_f with decreasing d associated with the grain boundary anelastic process (GBAP) activated above 200 K are commonly observed. GBAP in the nanostructured Al is hardly modified by alloying with Si and Cu, and is very similar to GBAP reported in nanostructured Ag and Au. It is indicated that the elastic property of Al-Si(Cu)_sp, Al_sp, Al-Si(Cu)_ve and Al_ve nanocrystalline films is governed by GBAP, the internal stress and the surface oxide layer.