Yield criterion of an fcc polycrystal under combined loadings

Abstract

The yield criterion of an fcc polycrystal under combined loadings is derived based on a newly proposed polycrystal model. The single crystal is assumed to be non-hardening. Cases of biaxial tension and tension-torsion tests are all studied. It is shown that the macro yield stress component of the polycrystal can always be identified with the critical resolved shear stress τ0 multiplied by some orientation factorM. A Monte Carlo procedure is used to evaluateM. The results of the present model are found in reasonable agreement with those of the Taylor-Bishop-Hill model, and in excellent agreement with the Mises' criterion.