An evaluation of the saturation hardness in an ultrafine-grained aluminum 7075 alloy processed using different techniques

Research paper by Shima Sabbaghianrad, Terence G. Langdon

Indexed on: 02 Apr '15Published on: 02 Apr '15Published in: Journal of Materials Science


A commercial Al-7075 alloy was processed by the severe plastic deformation (SPD) procedures of equal-channel angular pressing (ECAP) and high-pressure torsion (HPT) and by a combination of these two techniques. The results show samples processed by a combination of ECAP and HPT have smaller grain sizes and higher saturation hardnesses than samples processed separately by ECAP or HPT. Microstructural observations reveal grain refinement after each SPD technique, and the minimum grain size was ~200 nm after processing by a combination of ECAP for eight passes and HPT for 20 turns. It is demonstrated that the saturation hardness is dependent upon the microstructure of the sample introduced in any processing step prior to the HPT processing.