FIRST-PRINCIPLES STUDY ON THE MECHANICAL PROPERTIES OF Al1- x TM xP

Using first -principles calculations, the mechanical properties of orthorhombic phase Al 1-x TM x P (x = 0.0625, 0.125, 0.25; TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) crystals were studied. By analyzing the mechanical stability, it was found that Al 0.75 Zn 0.25 P is mechanical unstable, and the rest all mechanical stable. The mechanical properties of Al 1-x TM x P were studied, including Bulk modulus, shear modulus, Young's modulus, Poisson's ration, ductility, Vickers hardness, and elastic anisotropy. It was found that Al 0.75 Ni 0.25 P has the largest Bulk modulus, the largest Poisson's ratio. Al 0.75 Ni 0.25 P has the smallest shear modulus, the smallest Young's modulus and the smallest Vickers hardness. The Al 0.75 Ni 0.25 P has the best ductility. Al 0.75 Ni 0.25 P and Al 0.75 Cu 0.25 P show strong elastic anisotropy, and the Al 0.75 Cu 0.25 P has the largest elastic anisotropy. Through the study of the mechanical properties of Al 1-x TM x P, it was found that doping Ni into AlP is an effective means to tune its mechanical properties.