![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
The low-temperature yield stress of a γ′ (Ni3Al) matrix–γ (Ni) precipitate ‘inverse’ superalloy, containing 40% Ni precipitates (γ), is calculated by discrete-dislocation simulations. Two different precipitate sizes and two anti-phase boundary energies are considered. The results of these simulations are compared with corresponding results from γ–γ′ superalloys (S. Rao, T.A. Parthasarathy, D. Dimiduk, et al., Phil. Mag. 84 3195 (2004)). In general, the results show that precipitation hardening in inverse superalloys is weaker than for regular superalloys. Similar to studies of superalloys, many of these results can be rationalized from the results of simulations on simple homogenized precipitate structures. The Hirsch, Kelly and Ardell precipitation-strengthening model (Metall. Trans. A 16 2131 (1985); Phil. Mag. 12 881 (1965); Trans. Jpn. Inst. Metals 9 1403 (1968).), developed for low-stacking-fault-energy spherical precipitates in a high-stacking-fault-energy matrix, adapted for inverse superalloys, shows qualitative agreement with the simulation results for spherical γ precipitates.
Acknowledgements
This work was supported by the Air Force Office of Scientific Research (AFOSR) and the Defense Advanced Research Projects Agency (DARPA). S. I. Rao, T. A. Parthasarathy and P. M. Hazzledine acknowledge support from Air Force contract number F33615-01-C-5214 with UES Inc.