The low-temperature yield stress of a γ′ (Ni3Al) matrix–γ (Ni) precipitate `inverse' superalloy, containing 40%Ni precipitates (γ), was calculated by discrete-dislocation simulations. Two different precipitate sizes and two anti-phase boundary energies were considered. The results of these simulations were compared with corresponding results from γ–γ′ superalloys. In general, the results showed that precipitation hardening in inverse superalloys was weaker than for regular superalloys. Similar to studies of superalloys, many of these results could be rationalized from the results of simulations on simple homogenized precipitate structures. The Hirsch-Kelly-Ardell precipitation-strengthening model, developed for low-stacking-fault-energy spherical precipitates in a high-stacking-fault-energy matrix, adapted for inverse superalloys, showed qualitative agreement with the simulation results for spherical γ precipitates.

Discrete Dislocation Simulations of Precipitation Hardening in Inverse Superalloys. S.I.Rao, T.A.Parthasarathy, D.M.Dimiduk, P.M.Hazzledine: Philosophical Magazine Letters, 2006, 86[4], 215-25