On the Twinnability of Face-Centered Cubic Metals in Deformed Microstructures

作者：Matthew Daly, Ritesh Jagatramka · 发表于：arXiv (Cornell University) · 年份：2021 · 研究领域：Microstructure and mechanical properties、Microstructure and Mechanical Properties of Steels、Metallurgy and Material Forming

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 pr...