  The competition between deformation twinning and dislocation slip underpins
the evolution of mesoscale plasticity in face-centered cubic materials. While
competition between these mechanisms is known to be related to the critical
features of the generalized stacking fault energy landscape, a physical theory
that tracks competition over extended plasticity has yet to emerge. Here, we
report a methodology to predict the evolution of this competition in deformed
microstructures using intrinsic material parameters. Our approach implements
kinetic Monte Carlo simulations and analytical modeling to produce a
constitutive framework for deformation twin evolution in face-centered cubic
metals that is free of empirical fitting or phenomenology. These efforts are
leveraged to derive a set of physical relations for strain partitioning, which
provide kinetically-weighted predictions for the contributions of each
mechanism to plasticity. The culmination of this effort results in a new
twinnability parameter that tracks the competition between deformation twinning
and dislocation slip over extended plastic deformation. In contrast to previous
twinnability parameters, this criterion considers deformation history when
weighing mechanistic competition. This parameter therefore extends previous
theories for the competition between these mechanisms to include deformation
beyond incipient events. This analysis finds direct applications in work
hardening and crystal plasticity models that have previously relied on
phenomenological relations to predict the evolution of deformation twin
microstructures.
