Effect of Feed on Sub-surface Deformation and Yield Strength of Oxygen-free Pitch Copper in Machining

The article deals with the influence of the machining induced surface integrity on tensile properties of 99.99% purity Oxygen-Free Pitch copper (OFC), used in nuclear and research facilities. The increase in the feed in machining was found to lead to an increase, up to 55%, in yield strength of the OFC specimens. Intensive sub-surface deformation and a high degree of work-hardening in the near-surface layer are attributed to this effect. Increase of feed resulted in an increase of deformation depth ɛIII and work-hardening ΔH detected via SEM and nanoindentation. The correlation coefficient between the tensile properties and sub-surface deformation was found to equal R = 0.983.