Revealing grain coarsening and detwinning in bimodal Cu under tension

Abstract Metals with a bimodal grain size distribution have been found to both high strength and good ductility. However, the coordinated deformation mechanisms underneath ultrafine-grains (UFGs) coarse grains (CGs) still remain undiscovered yet. In present work, Cu 80% volume fraction of recrystallized micro-grains was prepared by annealing equal-channel angular pressing (ECAP) processed ultrafine grained at 473 K for 40 min. The has an optimal strength-ductility combination (yield 220 MPa ductility 34%), larger shear fracture angle 83° area reduction 78% compared as-ECAPed UFG 410 MPa, 16%, 70°, 69%). Grain refinement detwinning growth twins were observed in fractured tensile specimen. underlying analyzed discussed.