Mechanical analysis of the strain-hardening exponent under tensile deformation

It has been experimentally proved that strain hardening exponent has very strong sensitivity to structure. The measuring result of precise experiment indicated that the variational laws of n(o)(the strain hardening exponent under constant velocity), n(epsilon) (under constant strain rate) and n(p)(under constant load) with epsilon strain are entirely different. Considering the structure sensitivity in superplasticity and plasticity which means that the strain hardening exponent is related to strain as well as strain rate), this paper deduces the analytical expressions for n(o), n(epsilon) and n(p) from the state equation. Thus, the mechanical essence of n(o), n(epsilon); and n(p) corresponding the change of epsilon is revealed. And the experimental results on typical material Zn 5%Al are interpreted successfully which show reliability of the theory.