The relationships between tribological behaviour and heat-transfer capability of Ti6Al4V alloys

The heat-transfer capability affects the tribological properties of Ti6Al4V alloys. In present paper the friction and wear behaviours of Ti6Al4V alloys dry sliding against GCr15 steel were investigated on a high-speed pin-on-disc tribometer. Friction and wear tests were carried out at sliding speeds from 30 to 60 m/s and at contact pressure ranging from 0.33 to 1.33 MPa. In order to change the heat-transfer capability of Ti6Al4V pin, one group of pins were Ti6Al4V alloys, another group of pins made of two parts were Ti6Al4V alloy and copper. The dynamic sliding temperatures of Ti6Al4V alloys were measured using thermocouples. Morphology and composition of the surface and subsurface for Ti6Al4V alloy were examined by means of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The tests results were used for investigation of the relationship between sliding interface temperature, microstructure, friction coefficient, wear rate and heat-transfer capability. Finally, it is observed that heat-transfer capability enhancement is of great benefit to reducing the sliding interface temperature for Ti6Al4V alloy. Furthermore, advance in heat-transfer capability is favorable for increase in friction coefficient of Ti6Al4V/GCr15 pairs and in resistance to wear of Ti6Al4V. And moreover, the weight of GCr15 disc was changed from increase to loss. This indicates that transition of wear mechanism exists.