Electronic, Elastic Structure and Phase Stability of TaRu Shape Memory Alloys

The phase stability and electronic structure of TaRu shape memory alloys are studied using full-potential linearized augmented plane wave method (FP-LAPW) on the basis of the density functional theory (DFT). The calculated equilibrium volumes are about 32 3 and 30 3 for β-, β and β phases using the generalized gradient approximation (GGA) and local density approximation (LDA), respectively, in good agreement with the experimental values. The β-phase is favored by about 85 meV/f.u. than the β-phase. The value of the density of states at the Fermi energy, confirms that the β phase is the ground state equilibrium phase of TaRu at low temperatures, in agreement with the experimental findings.