Friction-wear Characteristics Of TiAlN Film Prepared On The Surface Of TA19 Alloy

Titanium alloy has the advantages of high specific strength,good corrosion resistance and high heat resistance.It has been widely used in aircraft structural materials for the manufacture of important aircraft structural components such as aero-engine fans,compressor discs and blades.TA19alloy has a low density and is a high Al equivalent of?-type medium strength titanium alloy.It is especially suitable for the manufacture of various welded parts and is an ideal material for high temperature applications,However,the wear resistance of TA19 alloy is poor,which limits its application,in order to solve this problem,this paper intends to improve the wear resistance of TA19alloy surface by reactive magnetron sputtering.In this paper,a TiAlN hard film was prepared on the surface of TA19 alloy by reactive magnetron sputtering.Firstly,the orthogonal experiment was designed to analyze the influence of sputtering process power,working pressure,Ar/N₂ flow ratio and working time on the performance of TiAlN film,and the best process parameters were obtained.Then the microstructure and mechanical properties of TiAlN films prepared under the optimum process parameters were observed.The surface,cross-section,composition and phase structure of the films were analyzed by SEM,EDS and XRD.The size of the microhardness,roughness and bonding strength of the films were tested.Finally,the ball-disk wear test was carried out to investigate the effects of load,speed and temperature on the friction and wear properties of TA19 alloy and TiAlN film.The results show that:?1?The optimum process parameters for the preparation of TiAlN thin films by reactive magnetron sputtering are:sputtering power 250W,working pressure 0.8Pa,argon nitrogen flow ratio30:40,working time 3h.?2?The surface of the TiAlN film prepared under the optimal process parameters is dense and non-porous,and the thickness is about 3.6?m;the XRD diffraction results show that the main phase composition of the film is TiAlN phase and TiN phase;the average microhardness value of TiAlN film reaches 1208.2 HV_0.1,nearly 3 times higher than the substrate;the roughness of the TiAlN film is 7.68 nm,which reduces the surface roughness of the substrate;the bonding strength of the TiAlN film and the substrate reaches 53.3N.?3?The ball-disk wear test results show that the friction coefficient of the TiAlN film is significantly lower than that of the TA19 substrate after magnetron sputtering on the TA19 alloy substrate.The wear rate and specific wear rate of the TiAlN film are reduced by an order of magnitude compared to the TA19 substrate,respectively.At a high load of 330g,the TiAlN film was broken and some areas were peeled off.When the sliding speed is changed from low speed to high speed,the wear form of the TiAlN film is converted from slightly abrasive wear to more abrasive wear and oxidative wear.Under the high temperature condition of 500°C,the surface of the film is oxidized and worn,resulting in a less dense oxide layer,but still has a protective effect on the substrate.