Hydrogen-induced enhancement of ductility of fcc iridium: A first-principles study

Abstract

First-principles FLAPW-GGA calculations have been performed to understand the response of the structural, elastic and electronic properties of fcc Ir to the presence of interstitial hydrogen in comparison with fcc Pd. The Cauchy pressure and the Pugh's criterion (ratio of shear modulus and bulk modulus) were used to assess the trends for brittle/ductile behavior of Ir and Pd accompanying hydrogen insertion. An unconventional hydrogen-induced enhancement of ductility of iridium was predicted simultaneously with its “metallization” owing to the growth of the near-Fermi density of states.