High tensile ductility and strength in bulk nanostructured nickel

Cryomilling and quasi-isostatic (QI) forging processes were used to prepare bulk dense multimodal and bimodal nanostructures (NS) Nickel with tensile ductility of 42% and 49% and yield strengths of 457 and 312 MPa. Bulk NS materials were synthesized by two-step approach involving synthesis and consolidation of NPs or nanopowders, or a one-step approach such as severe plastic deformation (SPD). The purity and density of bimodal NS Ni is found to be 99.7% and 8.85 g cm^-3 respectively. The uniform elongation of the bi-Ni (28%) is found to be larger than that of the multi-Ni (24%), but smaller than that of the cross-grained (CG) Ni (34%). The dimples in the multi-Ni and bi-Ni are smaller than those in the CG Ni due to their smaller grains, and elongated due to void nucleation and coalescence through shear fracture.