Three-dimensional model of precipitation of ordered intermetallics
- Rutgers Univ., Piscataway, NJ (United States). Dept. of Ceramics and Materials Engineering
The development of the two-phase (f.c.c. + L1{sub 2}) coherent microstructure in the prototype Ni-Al superalloy is studied by using the three-dimensional computer simulation technique. The dynamics and morphology of the microstructure evolution are described by the three-dimensional version of the stochastic time-dependent kinetic equation which explicitly includes the coherency strain, elastic anisotropy and L1{sub 2} ordering of the precipitate phase. The input parameters, the crystal lattice misfit, elastic moduli, interfacial energy and equilibrium compositions of the coexisting phases are taken from the published independent measurements. The simulation results demonstrate that the strain accommodation in the microstructure evolution results in the cuboidal-like precipitates faceted by the {l_brace}100{r_brace} planes. The size of the precipitates are always single-domain particles with no antiphase boundaries. This effect is associated with the ordered structure of precipitates. It causes the slowing down of the coarsening kinetics since it excludes the agglomeration of the out-of-phase precipitates in one particle. As has been shown previously, the latter is a very important coarsening mode in an absence of ordering.
- OSTI ID:
- 357919
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 7 Vol. 47; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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