Mechanical properties and electronic structures of diverse Pt-Al intermetallics: First-principles calculations

Binary Pt-Al intermetallics are of growing interest in high-temperature technology. Here we investigate the structural stability, mechanical property and electronic structure of Pt-Al intermetallics by means of first-principles techniques. Our results reproduce the stable phases, Pt5Al3, alpha-PtAl, alpha-Pt2Al3, and PtAl2. I4/mcm-PtAl5 is firstly predicted to be stable phase. The bulk moduli of Pt-Al intermetallics generally enhance with the increasing of Pt concentration. The Pmm-Pt3Al exhibits the maximum values of bulk, shear and Young's modulus among all Pt-Al intermetallics, while PtAl5 also possesses outstanding shear and Young's modulus among Al-rich phases. Al-3p electrons are delocalized for all Pt-Al intermetallics, while the delocalization of Pt-5d electrons only shows up in Pt-rich phases. Relatively strong hybridization between Al-Al atoms for PtAl5, and Pt-Al atoms for Pm (3) over barm-Pt3Al, is crucial to understand their outstanding structural stabilities and mechanical properties. (C) 2016 Elsevier B.V. All rights reserved.