Friction reduction in bulk nanostructured material subjected to severe plastic deformation

A bulk nanostructured copper sample is produced using the Single-Step High Pressure Torsion (SIHPT) process. The microstructure of the sample produced through Severe Plastic Deformation (SPD) yields a combination of coarse and fine grains. There is a dearth of reported investigations dedicated to the study friction of the SPD-processed samples. In the current study, Atomic Force Microscopy (AFM) in Lateral Force Mode (LFM) is used to study the frictional behaviour of SIHPT-produced bulk nanostructured samples. Friction reduction up to 25% is noted with the resultant combined coarse and fine grain NS copper samples. Although, the effect of HPT-based nanostructuring has not hitherto been reported in literature, the results show good agreement with the findings of similar works for the ECAP produced samples.