  Many time-dependent deformation processes at elevated temperatures produce
significant concurrent microstructure changes that can alter the mechanical
properties in a profound manner. Such microstructure evolution is usually
absent in mesoscale deformation models and simulations. Here we present an
integrated full-field modeling scheme that couples the mechanical response with
the underlying microstructure evolution. As a first demonstration, we integrate
a fast Fourier transform-based elasto-viscoplastic (FFT-EVP) model with a
phase-field (PF) recrystallization model, and carry out three-dimensional (3D)
simulations of dynamic recrystallization (DRX) in polycrystalline copper. A
physics-based coupling between FFT-EVP and PF is achieved by (1) adopting a
dislocation-based constitutive model in FFT-EVP, which allows the predicted
dislocation density distribution to be converted to a stored energy
distribution and passed to PF, and (2) implementing a stochastic nucleation
model for DRX. Calibrated with the experimental DRX stress-strain curves, the
integrated model is able to deliver full-field mechanical and microstructural
information, from which quantitative description and analysis of DRX can be
achieved. It is suggested that the initiation of DRX occurs significantly
earlier than previous predictions, due to heterogeneous deformation. DRX grains
are revealed to form at both grain boundaries and junctions (e.g., quadruple
junctions) and tend to maintain a triple line with old grains during the
growth. The resulted stress redistribution is found to have a profound
influence on the subsequent dislocation evolution and the softening.
