Study On The Preparation And Properties Of TiAlVN Films By Magnetron Sputtering On The Surface Of Gun Steel

The gun barrel life is a significant index in service.Chromium plating is one of the most common methods to improve the service life of gun barrel,but it is brittle and easy to fall off.Although they are many emerging life extension technologies,taking the environmental protection and economic factors into consideration,gun barrel life is still a difficult problem to solve.Therefore,it is extremely important to expand the life extension technology of the gun barrel.In the thesis,TiAlN films with different Al/Ti were deposited on the gun steel surface by magnetron sputtering.Then,TiAlVN films with different V content were prepared on the basis of optimizing the process parameters.The effects of different Al/Ti on the properties of TiAlN films and the effects of V content on the properties of TiAlVN films were systematically investigated.Among of them,the microstructure,chemical composition of the films were analyzed by means of metallographic microscope,confocal laser scanning microscope and scanning electron microscope.The phase structure of the films was analysed by X ray diffractometer.The nano hardness,elastic modulus and friction wear characteristics of the films were measured by G2000 Nano Indenter and MFT-4000 type multifunctional material surface performance tester.The thermal shock resistance of the films was analyzed by SX2-6-13 box type resistance furnace.The experimental results showed: TiAlN films and TiAlVN films prepared by magnetron sputtering are smooth and compact,and the surface roughness can reach ten nanometer level.At the same time,more uniform nanocrystalline structure can be obtained.The two kinds of films are TiN based substitutional solid solutions,which are mainly based on TiN(200),(220)oriented crystal growth.Compared with gun steel substrate,the hardness and elastic modulus of the films,were improved obviously.And the hardness and elastic modulus of Al/Ti=1.35 in TiAlN film could be increased by 3.4 times and 1.38 times.When Al/Ti is 0.88,the hardness of TiAlN film decreases slightly,but the thermal shock resistance is the best.After comprehensive consideration,the parameters of Al/Ti=0.88 are chosen as the basic parameters of adding V elements.Compared with the TiAlN film,the grain size of the TiAlVN film with the addition of V element was increased,but the arrangement is more uniform and compact.Secondly,the mechanical properties are improved to a different degree,increase nearly 1.3 times in terms of hardness.In particular,the wear resistance is significantly improved.The average friction coefficient is reduced by about70%,and the main wear mechanism is abrasive wear and oxidative wear.Moreover,the thermal shock performance is excellent,when the TiAlVN film is V=12.25 at%,the thermal shock cycles are 1.55 times of the TiAlN film.This research extends the original idea for the gun barrel life extension technology,and provides technical support and reference for the production practice.