Mechanical properties of copper after compression stage of high-pressure torsion

The mechanical properties and microstructure of commercial purity copper subjected to various pressure values in a compression stage of high-pressure torsion (HPT) were investigated here by analyzing microhardness, deformed geometry, and electron back scattering diffraction images along the radial direction of the compressed disks. Compression before torsion significantly increases the hardness and low angle grain boundary in the center as well as in the intermediate and edge regions. It is found that the compressive strain is the reason for the increased strength and refined grain size in the center region during HPT. This result sheds light on the strategy for achieving microstructure and property homogeneity in HPT.

► Hardness and structure of Cu processed by HPT was studied.
► Compression increases the hardness and LAGB in the center as well as intermediate and edge regions.
► Compressive strain is the reason for the increased strength and refined grain size in the center, which contributes to the uniform hardness distribution in HPT processed materials.