Structural mechanism of plastic deformation of Al/а-Si multilayer foils at heating under load

Abstract

Abstract Al/Si multilayer foils were produced by layer-by-layer vacuum deposition of component vapour phases on the substrate at 150°С temperature. It is shown that the structure of as-deposited foils is characterized by alternation of layers of aluminium and amorphous silicon. At foil heating under load in the temperature range of 180 … 230°С, an increase of plastic deformation rate is observed. Investigations of the change of foil structure showed that increased plasticity can be due to aluminium-induced silicon crystallization. The process of silicon crystallization is accompanied by fragmentation of its layers and formation of a composite structure, consisting of aluminium matrix, crystalline silicon particles and pores. When temperature of the order of 450–500°С is reached, the rate of foil plastic deformation rises abruptly. Analysis of structural changes in the foil leads to the assumption that intensive plastic deformation of the foil is realized by the mechanism of intergranular slipping of aluminium grains, accommodation of their displacement being facilitated by presence of pores.