Evaluation of the interface stability of Al/AlN multilayered composites under thermal stress

Abstract Al/AlN multilayered composites with different individual layer thicknesses (25, 250 nm) on Si substrate were fabricated by magnetron sputtering and subjected on thermal cycle testing from room temperature up to 500 °C and then tested under nanoindentation. There is a significant layer thickness effect on the interface damage behavior of the Al/AlN multilayer: when the individual layer thickness is 250 nm, it was found that the hillocks damage on the surface of the multilayer, while the damage behavior was dominated by the interface delamination and fracture between ceramic layers and metallic layers with smaller individual layer thickness (25 nm). The deformation behavior transferred from inhomogeneous shear band deformation (severe thinning and thickening of layer thickness caused by dislocation pile-ups in Al layer) at submicron scale to homogeneous shear bands deformation (heterogeneous interface instability) caused by the grain boundary sliding and the grain rotation in Al layers.