(V) Optimization of Interfacial Energy for Langer-Schwartz Based Precipitation Simulations

Precipitation kinetics were investigated in select Fe, Ni, and Al alloys using a CALPHAD based precipitation model based on Langer-Schwartz theory. Thermodynamic and kinetic data were taken from commercially available CALPHAD software. Application of this model in a predictive capacity is limited by lack of reliable interfacial energy data for precipitates. By performing simulations with thermal histories, nucleation sites, and precipitate morphologies that closely replicate experimental data found in literature, interfacial energy was adjusted until volume fraction and mean radius values closely matched the published data. Using this technique, interfacial energy values have been determined for carbides in Grade 22 low alloy steels, delta phase in Ni 625 and 718, S-Phase in Al 2024, and QPrime and Beta Prime in Al 6111, and can be used for future predictive precipitation simulations.