Ab-initio investigation of structure and mechanical properties of PtAlTM ternary alloy

Although Pt-Al alloy is a promising thermal barrier coating, the structure and mechanical properties of Pt-Al ternary alloy are unknown. In this paper, we use of ab-initio calculations to investigate the structural feature and mechanical properties of PtAlTM (TM = Zr, Hf, Nb, Mo and W). The calculated results show that PtAlTM is a thermodynamically stable. Importantly, PtAlW is more thermodynamically stable than that of other PtAlTM. We find that PtAlTM has strong deformation resistance along the a axis in comparison to c axis. PtAlTM has strong volume and shear deformation resistances. In addition, PtAlTM exhibits better ductile behavior. In particular, the volume deformation resistance, shear deformation resistance and elastic stiffness of PtAlW are stronger than that of other PtAlTM. The calculated electronic structure indicates that the high elastic modulus of PtAlTM is attributed to the zigzag bonding state because of localized hybridization between atoms.