Study On Reparation And Performance Of Laser-Modified Tic/β-Ti Composite Coatings

Titanium alloy has excellent property,although Ti6Al4V alloy is a well-know commercial titanium based alloy for aeronautical and aerospace industry,the wear resisting property should be explored,in order to widen the application scope,the paper uses laser melt in-suit forming reaction technology to prepare TiC reinforcedβ-Ti composite coating on Ti6Al4V alloy.Mechanism of in-suit forming reaction coating on the surface of Ti6Al4V alloy and frictional wear property are studied by Scanning Electron Microscope, X-ray Diffraction,Schematic of Wearing Test Machine,Micro Hardness Tester and other equipments.Thermodynamics analysis shows that using Cr₃C₂-Ti powder to transform TiC particles reinforced titanium based composite by laser-cladding process is feasible.The reaction is spontaneous.Though designing the ratio of Cr₃C₂-Ti powder,the paper prepares successfully TiC particles reinforced titanium based composite coating by laser irradiation in controlled atmosphere processing booth.Alloying component of coating dilutes by controlling alloying element of substrate with appropriate processing parameter,The substrate of composite depends on the ratio of the melt alloy powder,β-Ti which is suitable to displaying the wear resisting property was formed in laser melt,freezing,crystallizing replacement by controlling the ratio.The frictional wear property of the TiC/β-Ti composite in comparison with Ti6Al4V alloy is studied.The results show that the abrasion of Ti6Al4V alloy is characterized as sticking abrasion,the abrasion of TiC/β-Ti composite coating inverts to lightness abrasion. The result of the observation of the grinding crack and the grinding of the composite coating shows that during the wear process,the in-situ formed TiC particle shows little tendency to peel off from the matrix andβ-Ti substrate which is rich of Cr is able to deformed simultaneously,thus TiC particles and it might have good compatibility.The abrasion mechanism of the composite coating may be a series of micro-plough, push-millings and micro-cracking.In the experiment,there is an optimal volume fraction of the reinforced TiC particles.After laser-cladding process,the wear resisting property increases 3.4 times to substrate.