Tailoring the hydrogenated mechanism of Pt3Al from first-principles investigation.

Pt–Al compounds are promising high-temperature structural materials. However, the hydrogenated behavior of Pt 3 Al is still unclear. To explore the hydrogenated mechanism, we apply the first-principles method to investigate the role of hydrogen (H) in Pt 3 Al. Here, the cubic and tetragonal Pt 3 Al are considered. Based on the hydrogen occupied position, three H-doped sites are designed in cubic and tetragonal phases. It is found that the hydrogen is a thermodynamic stability in two Pt 3 Al phases. Compared to the cubic Pt 3 Al, the hydrogen prefers to occupy the octahedral interstice (H(2) site) of the tetragonal Pt 3 Al. Importantly, the H-doped Pt 3 Al is a mechanical stability. In particular, it is found that the hydrogen weakens the volume deformation resistance, shear deformation resistance and elastic stiffness of Pt 3 Al. But the hydrogen improves the ductility of Pt 3 Al due to the electronic interaction between hydrogen and Pt 3 Al. Naturally, the low elastic properties are that the introduction of hydrogen weakens the localized hybridization between Pt atom and Al atom, and forms the H–Pt bond. In addition, the hydrogen also weakens the Debye temperature (θ D) of Pt 3 Al. • Hydrogenation mechanism of Pt 3 Al compound is studied. • It is found that hydrogen is a thermodynamic stability in Pt 3 Al compound. • The hydrogen weakens the elastic modulus and Debye temperature of Pt 3 Al compound. • The hydrogen weakens electronic interaction between Pt atom and Al atom. [ABSTRACT FROM AUTHOR]