Harmonic structure, a promising microstructure design

The harmonic structure is a recently introduced concept paving the way for engineering metallic materials to achieve excellent mechanical performance. They consist of soft coarse-grained regions (Core) that are three-dimensionally surrounded by connected network hard ultra-fine grained (Shell). interaction in these Core–Shell produces synergistic effect, during plastic deformation, leading superior properties extremely important practical applications. current review paper aimed at providing critical assessment on this novel microstructure design. It also involves identification and discussion key issues which deserve additional studies.