Improvement of the fretting wear resistance of Ti6Al4V by application of hydrostatic ball burnishing.

Abstract

The objective of the research was to improve the fretting wear resistance of titanium alloy by hydrostatic ball burnishing. Ball burnishing is an economic surface finishing process for wide range of components. It is based on pressing and rolling a hydraulically floated ball along the surface of the component being treated, to plastically deform surface asperities. This process generates a deep field of compressive residual stresses (up to 1.0 mm) in the outer layers of the component. The compressive residual stresses and the high quality of the surface finish improve the wear resistance of the part. Experiments were made using ball-on-disc tribotester in oscillatory motion. 100Cr6 sphere co-acted with a disc made of titanium alloy Ti–6Al–4V. The friction force was monitored as a function of time during the test. Wear of disc was measured after the test using the non-contact 3D surface profiler. The optimal ball burnishing parameters have been determined after conducting the Taguchi L9 matrix experiment. During tests, normal load was kept constant at 50 N within the contact with frequency of 50 Hz and displacement amplitude of 0.02 mm. The results confirmed that hydrostatic ball burnishing had a significant influence on friction and wear.