Study on dual rotary fretting wear behavior of Ti6Al4V titanium alloy

Abstract

To investigate the wear mechanism and microstructural evolution of Ti6Al4V titanium alloy under the condition of dual rotary fretting (DRF), which mainly exists in the interfaces of ball-and-socket joints with the motion combing torsional fretting with rotational fretting. Using the Ti6Al4V titanium alloy flat specimen against the 52100 steel ball to investigate the DRF and damage behavior were carried out under the normal load of 50 N with different tilt angles (10°~60°) and varying angular displacement amplitudes (0.25°~5°). The morphologies of wear surface and their cross-sections were analyzed by scanning electron microscopy, electron probe microscopy analyzer and a surface profilometer etc. The results are as followed: 1) The DRF wear behavior of Ti6Al4V is strongly dependent on the tilt angle, which decides the scale for combination of rotation component and torsion component. 2) Fx/Fn curves presents different varied trends in different fretting regimes. The fretting wear is slight in partial slip regime due to the oxidative wear, and the surface bulge is formed in mixed fretting regime probably due to the plastic-flow, and in sliding regime, plough scratches caused by the abrasive wear. 3) As the tilt angle increase, DRF wear mechanism of Ti6Al4V titanium alloy transfers from oxidative wear to the abrasive wear. 4) The DRF damage of Ti6Al4V is the result of the competition between the rotational fretting component and the torsional fretting component. When the DRF behavior is mainly controlled by the torsional fretting component, the wear mechanism is the oxidative wear with the oxygen element distributing around the micro-slip circle zone. When the DRF behavior is mainly controlled by the rotational fretting component, the severe plastic deformation can be observed.