Ideal mechanical strength and interface cohesion property of Ir-base superalloys from first principles calculation

▶ Mechanical strength and interface property of Ir-base superalloys are calculated. ▶ The Ir3Hf bulk seems less brittle than f c c Ir, while Ir3Nb becomes more brittle. ▶ The chemical bonding in Ir3Nb is stronger and more directional than that in Ir3Hf. ▶ Descending sequence of mechanical properties of Ir and Ir3X is: Ir → Ir3Nb → Ir3Hf → Ir3Zr. ▶ The (1 0 0)-I interfaces are energetically favorable with high bond strengths.