Synergistic strengthening mechanisms of rhenium in nickel-based single crystal superalloys

EL Yue and T Yu and YJ Wang and CY Wang, INTERMETALLICS, 132, 107133 (2021).

DOI: 10.1016/j.intermet.2021.107133

A loading-unloading-reloading strategy via atomistic simulations is proposed to reveal the strengthening mechanisms of rhenium in nickel- based superalloys at ambient temperature. Simulations reproduce the experimentally observed increased flow stress with addition of rhenium. Besides the usual solid solution strengthening, two novel mechanisms are uncovered. One is that rhenium facilitates the dislocation nucleation and, thus, increases the propensity of forest dislocation interactions. The other involves a critical role of rhenium in promoting accumulation of sessile stair-rod dislocations, served as obstacles for the glissile dislocations. The three mechanisms synergistically render a stronger alloy, which is heuristic to design advanced superalloys in extreme environments.

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