Virtual Crystal Approximation of Pd-Ru-Zr System

Abstract The phase stability of Zr and Ru doped Pd system has been studied using the virtual crystal approximation (VCA) in density functional theory (DFT). Three possible VCA models have been set up for Zr and Ru doped Pd system, and elastic constants and tetragonal shear constant, bulk modulus and shear modulus, Young modulus and Cauchy press, density of states in Zr and Ru doped Pd system were also analyzed. The results show that Pd-5Ru-1Zr[T(3)] is the most stable phase in Pd-Ru-Zr system according to tetragonal shear constant, and Pd-10Ru-1Zr[T(2)] is the most brittle phase and has more directional bonding according to Cauchy press. Along with replacing Pd with Ru and Zr in the solution, the structure becomes unstable both energetically and geometrically, and the increase of Ru and Zr content can improve the strength of the chemical bonding and enhance the hardness of Pd-Ru system, but reduce their phase stability.