Improvement of strength and ductility in a gradient structured Ni fabricated by severe torsion deformation

The tensile deformation behavior and microstructure evolution of gradient structured (GS) Ni processed by severe torsion deformation (STD) were systematically investigated. The results show that the gradient shear strain from STD introduces gradient distributions of grain size, microhardness, frequency of low angle grain boundaries, Σ3 twins and geometrically necessary dislocations (GND) density along the radial direction. With the increasing...