Microstructural evolution and shear fracture of Cu–16 at.% Al alloy induced by equal channel angular pressing

Microstructural evolution and shear segmentation of Cu–16 at.% Al alloy with extremely low stacking fault energy (SFE) subjected to multiple-pass equal channel angular pressing (ECAP) were investigated. With increasing plastic deformation, the accommodation of the severe shear strain is transformed from the dislocation slip, stacking faults and deformation twins on the lattice scale to the microshear bands on the grain scale during one- and two-pass ECAP. However, shear fracture happened due to the formation of macroscale shear bands, which can be ascribed to its extremely low SFE leading to the easy saturation of microscale shear bands during plastic deformation during third-pass ECAP. Furthermore, the effects of the SFE on microstructures, grain refinement and shear fracture of various fcc metals were discussed.