ABSTRACT
This chapter reports the formation of dispersive shear bands in a hetero-structured Cu composed of coarse-grained (CG) and ultrafine-grained (UFG) zones. Microscale digital image correlation revealed that dense shear bands evolved in a stable manner over the whole gauge section. It has been recently reported that heterostructures with coarse-grained (CG) soft zones embedded in UFG or NS matrix can produce high strength while retaining reasonable ductility. Microstructure of the as-processed samples was characterized using electron back-scattered diffraction (EBSD) under an FEI Quanta 3D FEG instrument. The heterostructure induced the formation of dense and dispersive stable SBs in UFG/CG heterostructured Cu sample during tensile tests. The low strain hardening capability of UFG zone is a prerequisite for the nucleation of SBs. The long-range internal stress induced by elastic/plastic interaction between UFG and CG zones led to high stress concentration around zone boundaries, which promoted the nucleation of SBs from zone boundaries.
