Triple junctions network as the key pattern for characterisation of grain structure evolution in metals

Describing dynamic recrystallisation is challenging with existing material characterisation tools, which are typically based on grain boundary character distribution. This is one barrier to further developments in grain boundary engineering. We consider the network of triple junctions in copper alloys as the sub-structure that governs continuous dynamic recrystallisation and propose one descriptor of this sub-structure, referred to as the structural entropy. With the limited available characterisation data we demonstrate that the proposed descriptor correlates well with the evolution of the microstructure during severe plastic deformation. Importantly, our descriptor allows for elucidating micro-localisation features in copper alloys observed in some recent experiments.