Stable Properties of NbAl3 under High Pressure: Theoretical Predictions and First-Principles Calculations

Abstract

Nb-Al alloy compounds are expected to be high temperature structural materials. However, the low toughness and poor oxidation resistance are the main obstacles to hinder Nb-Al intermetallics from applications. In this paper, a new monoclinic phase of NbAl 3 was proposed by particle swarm optimization. Structural and mechanical properties of monoclinic phase were investigated using the first-principles method. The calculated enthalpies suggested that the known tetragonal structure was more stable than monoclinic structure from 0 to 200 GPa, but the ductility of monoclinic phase was better than that of tetragonal phase.