Experimental Study of Internal Variable Evolution in SS304L, at Multiple Rates and Temperatures

Abstract

Most metals exhibit a deformation-induced uniaxial yield strength asymmetry. Interpreted within the context of macroscale viscoplastic models, it is conventional to describe this yield strength asymmetry with an isotropic hardening variable, κ, and a kinematic hardening variable, α . The focus of this work was to conduct a series of reverse yield experiments to directly measure the evolution of α and κ in 304L stainless steel (SS304L) over large ranges of temperatures and strain rates. We found that the material exhibited inelastic behavior immediately on changing the straining direction. We discussed the ramifications of this behavior on our goal to directly measure α and κ within the context of an isotropic/kinematic hardening model framework. We also explored the capability of the model to simulate the behavior of SS304L under different loading conditions across a wide range of temperatures and strain rates.