Alloying effects of Ta on the mechanical properties of γ' Co3(Al, W): A first-principles study

The effects of Ta on the ideal strength, elastic properties and electronic structure of γ′-Co3(Al, W) were investigated using first-principles methods. The results indicate that the mechanical strength of Co3(Al, W) is restricted with the valence charge depletion of Co-Al bonds. The predicted enhancement of mechanical property by Ta additions is attributed to the Ta5d electrons participating in the ring-like bonding between Co3d and W5d. These results provide a new insight into the understanding of alloying effects on Co-base superalloys.