Study On Fretting Wear Properties Of Damage Tolerant Titanium Alloys

In this paper,the effect of different load,speed and hardness of titanium alloy matrix on the friction and wear properties of titanium alloy and the mechanism of subsurface crack growth was studied.The evolution of microstructure near the wear mark surface under different experimental conditions was studied by using laser confocal microscope.The friction and wear mechanism of titanium alloy in different environments was revealed by combining the change process of friction coefficient and wear rate of titanium alloy.The main contents of this paper are as follows:Firstly,the dry friction experiment of titanium alloy and silicon nitride ceramic ball was carried out.The influence of friction speed,load and hardness of titanium alloy matrix on friction coefficient and wear rate of titanium alloy was studied by variance analysis.The results show that the main factors affecting the tribological properties of titanium alloy are friction speed,load and hardness.The friction coefficient is larger when the friction speed is smaller,and the running in period is longer.The wear rate increases with the increase of load and speed.Secondly,the laser confocal microscope was used to observe the surface morphology of titanium alloy after wear,and the wear mechanism of titanium alloy under different load and speed was analyzed.The results show that the wear mechanism of titanium alloy under light load is mainly abrasive wear,with the increase of load,there are peeling pits on the surface of titanium alloy,and the wear mechanism is mainly peeling wear.With the increase of friction speed,the wear mechanism of titanium alloy is spalling wear and abrasive wear.Finally,based on the fracture mechanics and Hertz contact stress,the volume wear model of fatigue wear of titanium alloy is established to predict the wear volume of titanium alloy.The wear model reflects the quantitative relationship between the wear amount and its main influencing factors(including speed,load,material property,friction coefficient),and analyzes the experimental value and theoretical value of the wear volume.The results show that the relative error between the theoretical value and experimental value is between 10%and 20%,which proves that the wear model established in this paper is reasonable and effective.