Analysis of flow stress and size effect on polycrystalline metallic materials in tension

A model describing the size effect on the tensile strength of crystalline metallic materials is investigated. Using the nonhomogeneity of polycrystalline materials and free surface effect, the density of the geometrically necessary dislocations during tension is derived. Using the proposed model, an analysis of the effect of both specimen size and grain size on the tensile strength of the polycrystalline metallic materials is carried out.