Flow stress anisotropy

Understanding the mechanical anisotropy of metals is essential for many forming processes. 2 causes for anisotropy are treated: the deformation texture, which is related to the crystallography, and the deformation microstructure in the form of dislocation walls. Experimental data for the flow stress Variation in the rolling plane, which may be as high as 20%, are presented. The traditional Taylor model is applied to the data to account for the effect of texture. However, texture effects alone are not enough to explain all of the observed anisotropy. New models which take the combined effects of texture and deformation microstructure into account are presented. The models are based on the Taylor and Sachs models but modified with an anisotropic critical shear stress to account for the effect of the microstructure. The agreement between experimental data and model predictions is definitely better when microstructural contributions are included in the models.