Evolution of triple junctions’ network during severe plastic deformation of copper alloys – a discrete stochastic modelling

Proposed is a methodology for an accurate description of triple junctions’ network evolution in the course of severe plastic deformation (SPD). It is based on representations of polycrystalline solids with discrete combinatorial complexes, processes evolving different substructures (grains, grain boundaries, triple junctions) of these complexes, and methods for analyses of such substructures. It is demonstrated that the methodology can reproduce theoretical results available for the simplest case of quasi-homogeneous microstructure evolution, i.e. spatially random conversion of low to high angle grain boundaries during SPD. It is further shown that the proposed discrete approach can reproduce in a natural way results from recent experiments with copper alloys, where inhomogeneity development during SPD is strongly manifested. Finally, the evolution of different types of triple junctions and their connectivity is analysed to show that these substructure characteristics differentiate inhomogeneous from homogeneous evolution of the polycrystalline solid. It is suggested that such substructure characteristics can form the basis for characterisation of continuous dynamic recrystallisation process.