The development of hardness homogeneity in aluminum and an aluminum alloy processed by ECAP

Equal-channel angular pressing (ECAP) is an effective fabrication process for obtaining ultrafine-grained materials. This paper examines the development of homogeneity in materials processed by ECAP with emphasis on samples of pure aluminum and an Al-6061 alloy processed by ECAP for up to 8 passes at room temperature. The Vickers microhardness was recorded on the polished cross-sectional planes of each as-pressed billet and the results are plotted in the form of contour maps to provide a pictorial depiction of the hardness distributions throughout the cross-sections. The factors influencing the homogeneity are examined, including the die corner angle within the ECAP die and the number of imposed passes. It is shown that good homogeneity may be achieved through ECAP processing when the number of passes in ECAP is reasonably high.