Mesoscale Modeling of the Recrystallization of Waspaloy and Application to the Simulation of the Ingot-Cogging Process

摘要

Typical models of recrystallization based on the Avrami formulation cannot be applied to cases characterized by anisotropic material behavior (e.g., hot working of ingot structures) or several consecutive waves of partial dynamic and/or metadynamic recrystallization (as in multi-hit deformation). The primary processing of ingots by cogging poses challenges with regard to both of these aspects. The present work reports on a new meso-scale, mechanism-based model that has been developed for such problems and applied initially for Waspaloy. The model formulation comprises two main parts: a geometric framework and a set of equations that describe microstructure evolution due to the various driving forces. The geometric framework is based on so-called meso-structure units (MSUs), each of which represents an aggregate of similar grains. The MSUs evolve via nucleation-and-growth processes quantified by equations describing energy storage, nucleation, and grain-boundary migration. The model was tested on a prototypical cogging process using 3D-FEM simulations.