Molecular Dynamics Simulation of Temperature and Ti Volume Fraction on Compressive Properties of Ti/Al Layered Composites

Based on molecular dynamics simulation, this work investigated the influences of temperature and Ti volume fractions on the compressive deformation of Ti/Al layered composites. According to the simulation, the initial dislocations during compression are concentrated on the Al side, dominated by 1/6<211> and 1/6<112> dislocations, and the 1/2<101> and 1/6<211> dislocations cross the Ti/Al interface from the Al side to the Ti side. It is found that an increase in temperature helps dislocations to form at lower strains, which leads to a decrease in the compressive strength and an increase in the plasticity of the structure. As expected, the Ti volume fraction has a significant impact on the compressive properties of Ti/Al layered composites, and the compressive strength of the material increases with the increase in the Ti volume fraction. At temperatures above 400 K, the reduction rate of compressive strength becomes smaller, which is due to the formation of new ordered metal compounds between Ti and Al. When the volume fraction of Ti is lower than that of Al, plastic deformation mainly occurs on the Ti side, dominated by 1/6<112> dislocations. In contrast, the types of dislocations across the Ti/Al interface and on the Al side are dominated by 1/2<110> and 1/2<011>. When the Ti volume fraction becomes comparable with that of Al, the plastic deformation is transferred from the Ti side to the Al side, and the plasticity of the sample decreases. The optimal compressive properties of Ti/Al layered composites are observed at a Ti volume fraction of 40%, which provides guidance for the structural design of Ti/Al layered composites.