Pressure Dependency of Elasticity in α-TiZr Shape Memory Alloys

Abstract

Shape memory alloys are a group of materials with two noteworthy properties; shape memory effects and super elasticity thus they have attracted a number of industrial applications. Elasticity is the ability of a material to resume its normal shape after being stretched or compressed when the elastic limit is not exceeded. Titanium Nickel, copper-based and iron-based shape memory alloys are mostly applied in constructions sector but they face challenges of pressure dependency. To provide a solution, we investigated the pressure dependency of elasticity in α-TiZr shape memory alloy. Elastic constants, bulk modulus, Young modulus, shear modulus and Poisson’s ratio of α-TiZr shape memory alloy were calculated at different pressure (0-10GPa) using Quantum ESPRESSO code with post-processing of the data done using Thermo_pw code. Projector augmented wave pseudo-potential with Generalized Gradient Approximations (GGA) within Perdew, Burke, and Ernzerhof (PBE) exchange-correlation functional was applied in this study. Elastic constants; C11, C12, C13 C33, and C66 of α-TiZr shape memory alloy increase with pressure monotonically except C44 which slightly decrease linearly. Furthermore, Bulk modulus, Young’s modulus shear modulus and Poison’s ratio were also observed to increase with external pressure. This indicates that elasticity of α-TiZr shape memory alloy is improved when external force is exerted on crystal. The study of pressure dependency of elasticity in α-TiZr shape memory alloy provides information which may lead to adoption of this alloy in construction of intelligent reinforced concrete (IRC).