Structural optimization strategies for improving the maximum strength of gradient nanotwinned metals

Abstract

Many studies have shown that the excellent mechanical properties of gradient nanotwinned (NT) metals were primarily attributed to the unique micro-nano structure. In the present study, the motion resistance of mode Ⅱ and trans-twin dislocations is directly used to describe the effective stress in gradient nanotwinned (GNT) metals, combined with the modified hetero-deformation-induced (HDI) stress model, a constitutive model in connection with structural parameters has been successfully developed for the GNT metals with preferentially oriented. The proposed quantitative continuum plasticity model could investigate the role of gradient structure in tuning the strength of GNT metals. Furthermore, it has been found that the gradient element height and minimum twin thickness have significant effects on the strength of GNT metals. Therefore, the proposed model can be employed to optimize the mechanical property of GNT metals by controlling the gradient element height and minimum twin thickness.