Electronic, magnetic and mechanical properties of (Fe,Ni)2Nb from density functional theory

Abstract

A comprehensive analysis of the phase stability, electronic structure, magnetic and mechanical properties of the Laves phases Fe2Nb and Ni2Nb with C14, C15 and C36 structures has been presented using first-principles calculations. The effects of pressure on the formation energy and magnetic properties of Fe2Nb and Ni2Nb have been discussed. The effects of the composition on the mechanical properties of (Fe,Ni)2Nb have also been discussed. The results show that the electrons in Fe2Nb transfer from Fe to Nb, while the electrons shift from Nb to Ni in Ni2Nb. Fe2Nb and Ni2Nb with C14, C15 and C36 structure are of strong metallicity, and the metallicity of C15 phase is stronger than that of C14 and C36 types. The magnetic moments of Fe2Nb are similar to each other, and the value of C14-Fe2Nb is little bigger than that of the two others. The magnetic moments of Fe2Nb decrease with increasing pressure and the values decline evidently from 0 to 20 GPa. The hardness of C15 phase, with stronger metallicity, is lower than that of C14 phase and C36 phase. For (Fe,Ni)2Nb, the hardness decreases with increasing Ni and the ability to resist deformation increases with decreasing Ni.