Application of a Ternary Phase-Field Model to Precipitation Behavior in Ni-Al-Cr Alloys (Preprint)

摘要

A recently developed ternary phase-field model is applied to study the precipitation behavior in Ni-Al-Cr alloys. The effect of diffusivity and initial compositional/ordering profiles on the growth process of precipitates are examined. Specifically, the composition evolution with time in the precipitates is simulated and compared with experimental observations by Sudbrack et al. The simulation work reveals that the CR- trapping phenomenon can only be reproduced with no significant partitioning of Cr at the nucleation stage. By looking into the composition dependent diffusivity and thermodynamic driving force for both Al and Cr, it is found that the key difference resides in the much stronger composition dependence of the diffusivity of Al.