A novel technique to increase strain distribution homogeneity for ECAPed materials

Equal channel angular pressing as a material processing technique imposes high but in-homogeneous strain at the cross-section of the workpiece. In this research, cylindrical shaped commercial pure aluminum undergoes ECAP process up to four passes by route A using the conventional and covered tube casing (CTC) methods. The influence of CTC on strain distribution in the region of uniform longitudinal strain field was investigated experimentally and numerically. The Vickers hardness measurement at the cross-section of the aluminum samples indicated that there is more uniformity in the deformation during a single-pass ECAP in the CTC method compared with the conventional method and matched the simulated effective strain distributions. Moreover, based on volume fraction rule, an analysis has been developed to predict the required pressing force for CTC method.