Research On Sliding Wear Behaviors And Evaluation Parameters Of Pseudo-elastic TiNi Alloy

TiNi alloy is a kind of shape memory material with excellent performance,and its unique shape memory effect and pseudo elasticity have attracted much attention in the field of material science.Recent studies have found that TiNi alloy has good wear resistance under different friction types and its wear resistance is better than that of traditional wear-resistant materials.Up to now,researchers have not yet formed a unified understanding for the wear mechanism of TiNi alloy and its characterization parameters.Therefore,the systematically research on friction and wear behavior of TiNi alloy and its characterization parameters is helpful to widen its practical application in friction engineering.The sliding friction and wear behavior of pseudo-elastic TiNi shape memory alloy and 304 SS have been studied through sliding wear experiment.The experimental results showed that the wear resistance of pseudo-elastic TiNi alloy was much better than that of 304 SS,and the wear volume of 304 SS was basically linear with the wear load,which accorded with the law of Achard.However,the pseudo-elastic TiNi alloy has no obvious linear relationship,which did not conform to the law of Achard.The wear mechanisms of pseudo-elastic TiNi alloy were discussed base on the results of X-ray diffraction,scanning electronic microscope.The experimental results showed that pseudo-elastic TiNi alloy exhibited excellent wear resistance greatly benefits from its pseudoelasticity.Besides,the main wear mechanism of TiNi alloy was adhesive wear,abrasive wear and fatigue wear.The mechanical properties of pseudo-elastic TiNi alloy were investigated by micro-indentation test.The results show that pseudo-elastic TiNi alloy exhibited excellent wear resistance related to its E/H,? and W_t/?_r.Therefore,they can be used as parameters to evaluate the wear behavior of TiNi alloyTo clarify the effect of heat treatment and dual phase on wear resistance of TiNi alloy,the sliding friction and wear behavior of TiNi alloy with five aging treatment were studied in this paper.The results show that the microstructure of the TiNi alloy treated by aging is transformed from parent phase to martensite,and the friction and wear properties are related to the Pseudo elasticity and shape memory effect.Besides,there is no corresponding relationship between wear resistance and its E/H,? and W_t/?_r.Based on these results,a new parameter characterized the wear resistance of TiNi alloy was proposed.The Archard law was modified in this paper according to the wear experimental results and then verified the accuracy of the modified law.Instead of obeying Achard law,TiNi alloy obeys the following law:V=K'(E²?_SP^3/2S)/H^5/2.Finally,the electron work function of TiNi alloy was measured by scanning Kelvin probe technique.The relationship between the surface mechanical properties and the electronic work function of TiNi alloy under different aging temperature was studied.The results can be used to predict the wear behavior of TiNi alloy.