The Study Of Erosion Resistance Of TC4 Alloy By Magnetron Sputtering TiNi/TiN Composite Coatings

In modern aircraft manufacturing,TC4 titanium alloy is mainly used in aircraft structural parts,including engine rotating and non-rotating parts,such as fan disks,fan blades,compressor blades and so on.During the service process of the aircraft under the harsh environment conditions such as deserts,the solid particles carried by the air flow or the high speed droplets will cause serious erosion to the surface of the material,which is very easy to cause the loss of the parts and even the scrap.In order to improve the erosion resistance of TC4 titanium alloy,a kind of TiNi superelastic coating or TiNi/TiN composite coating was prepared by magnetron sputtering on the alloy surface.The phase structure,binding force,mechanical properties and electrochemical erosion resistance of the coating were characterized by XRD,SEM,nano indentation,scratch tester and electrochemical workstation,and the erosion resistance of the coating was evaluated by erosion test.The test results show that 550? is the most suitable substrate temperature for TiNi coating prepared by magnetron sputtering.The obtained TiNi coating is Ni-rich coating and B2 phase at room temperature.It has excellent hyperelastic properties,and the density of the coating is high,and the binding force to the TC4 substrate is good.The TiNi/TiN composite coating has high hardness,high modulus,and excellent erosion resistance.The erosion experiment show that the TiNi/TiN coating decreased by 43.54%lowest compared with the TC4 substrate,thus effectively improving the resistance to erosion and wear resistance of the TC4 components.The mechanism of TiNi/TiN coating with excellent erosion resistance is that the coating is composed of an erosion-resistant high-hardness surface TiN coating and a super-elastic TiNi coating,with good toughness and high hardness.The high strength of the TiN coating can effectively protect the TiNi interlayer until the TiN coating is slowly worn out by the abrasive particles.During this process,the superelastic phase transition mechanism of the TiNi layer has a very high response speed,effectively dissipates the energies carried by the particle impact surface during the erosion process,delays the stress and causes the propagation of cracks and damage,prolonging the service life of the TiN coating,effectively improving the erosion resistance of the material.In the preparation of TiNi/TiN coating,the over thickness of TiNi interlayer will reduce the erosion resistance of the material.In the preparation of TiNi/TiN coating,the over thickness of TiNi interlayer will reduce the erosion resistance of the coating.The addition of Ti layer can reduce the internal stress of the matrix and TiNi interlayer,and increase the erosion resistance of the coating performance.