Effect Of Heat Treatment And Friction Shear Deformation On Microstructure And Properties Of Laser Cladding Inconel718 Alloy

The service environment of high temperature alloy is bad and wear and fatigue failure will occur during the service.Laser cladding has become one of the key technologies of remanufacturing because of its high energy density,rapid solidification,wide material selection and good interface.In this paper,Inconel718 alloy coating was prepared on high temperature alloy substrate by laser cladding technology.The microstructure and properties of the alloy were restrained because of the inhomogeneity and segregation of the alloy and the microstructure and properties of laser cladding Inconel718 alloy could be improved by heat treatment and shear deformation.The microstructure characteristics of the different sections and regions of the cladding layer before heat treatment were analyzed,and the effects of micro segregation,precipitated phase and carbide distribution on the mechanical properties were analyzed.The existence form of carbides and precipitates in the cladding layer was analyzed by means of metallographic microscope,scanning electron microscope,energy dispersive spectrometer,X diffraction and transmission electron microscopy.The mechanical properties and hardness distribution of the cladding layer were analyzed by tensile testing machine and hardness tester.The results show that the microstructure and properties of laser cladding are anisotropic,and the mechanical properties are low.The effects of solution treatment temperature and holding time on the microstructure and Laves phase,and delta phase influence mechanism,discusses the changes after solution treatment,mechanical properties,hardness,provides the basis for multi heat treatment;analysis of multistage heat treatment microstructure,precipitation strengthening phase and its effect on the changes the mechanical properties.Results show that heat treatment can improve the segregation,reduce material anisotropy,improve material performance.The mechanical properties of the materials were up to the forging standard after HSTA treatment.The microstructure evolution process of the cladding layer was analyzed,and the hardness of the cladding layer was analyzed.The mechanism of grain refinement and dynamic recrystallization was studied.The results show that the friction shear deformation has a significant effect on grain refinement.