Thermo-kinetic orientation study on interface behavior of polycrystalline Cu-Nb composite by crystal plasticity finite element method

In this work, a 3-dimensional (3D) crystal plastic finite element method (CPFEM) combined with the qualitative analysis of slip thermodynamics and kinetics is applied to study the co-deformation behavior of heterophase interface and its relationships with the initial grain orientation or misorientation upon compression of FCC/BCC Cu-Nb polycrystalline metal matrix composites (MMCs). The present simulations well predict the interface instability of the 5-layered polycrystalline Cu-Nb composites arising from the onset and aggregation of the non-crystallographic bandlike concentrated strain. Meanwhile, by changing the grain orientation, the suppression or promotion of plastic shear localization can be realized, where the occurrence of interface instability depends not only on inhomogeneous stress fields, i.e., a single thermodynamic factor, but also on an implicit kinetic factor, i.e., misorientation. On this basis, a so-called artificial “coding” strategy by translating orientation-inhibited strain localization into implicit thermodynamic and kinetic information is presented to tailor the Cu-Nb MMCs, i.e., triggering as much plastic slip as possible from a thermodynamic perspective, while narrowing the misorientation as much as possible from a kinetic selection.