Molecular dynamics investigation of atomic mixing and mechanical properties of Al / Ti interface

Abstract

With the urgent lightweight demand in the aerospace engineering and transportation industries, Al / Ti composite structures have attracted much interest due to their excellent performances compared with conventional materials. Computational simulations have contributed to the understanding of both fundamental and practical aspects of fabrication of such composites and studying of their properties. The present work reports the results of studies based on molecular dynamics simulations on the mechanical properties of an Al / Ti composite obtained by compression combined with shear strain. Tensile properties of a nanosized Ti / Al composite consisting of two single crystals obtained after different compression rates are analyzed. The loading scheme applied in the present work is a simplification of the scenario experimentally realized previously to obtain Al-matrix composites. It is confirmed that uniaxial compression combined with shear deformation is an effective way to obtain the composite structure since severe plastic deformation facilitates the diffusion process. The results indicated that a symmetrical atomic movement took place in the Ti / Al interface during deformation. However, Al atoms diffuse into the Ti block easier than Ti atoms into the Al block. Tensile tests showed that fracture took place in the Al part of the final composite sample, which means that the interlayer region where the mixing of Ti and Al atoms is observed is stronger than the pure Al part.