Experimental Study On Grinding Properties Of Nickel Base Single Crystal Superalloy And Grinding With Textured Wheel

Nickel-based single crystal superalloy is the main material of high-end aero-engine blades because it has no influence of grain boundary.It has excellent thermal stability,corrosion resistance,oxidation resistance,high temperature strength and microstructure stability.However,nickel base single crystal superalloy,as a difficult to machine material,has poor grindability and high grinding temperature,which will lead to surface burns,microcracks,recrystallization and other phenomena,which are not conducive to obtain good surface quality and affect the service performance of components.Because of the "air barrier",the traditional pouring type can not achieve the ideal cooling effect,so it needs to adopt some advanced technologies to reduce the grinding damage,such as textured grinding wheel technology and nanoparticle micro lubrication(namql)technology.Moreover,single crystal materials are anisotropic,and different crystal faces and orientations have different mechanical properties,and different experimental results can be obtained by machining along different directions.Recrystallization occurs after single crystal material processing,which destroys the overall structure of the material and is also not conducive to the use of the workpiece.In this paper,the grinding performance of nickel base single crystal superalloy DD5 was studied,and the CBN textured grinding wheel was prepared by using PDC rectangular fiber.The t-namql test platform of textured grinding wheel was built,and the grinding test was carried out.(1)The effects of the anisotropy of DD5 material on the surface roughness,grinding force and subsurface deformation layer were analyzed.Based on the analysis of the experimental results,the(001)crystal plane and CBN grinding wheel were selected to carry out the follow-up experimental research;The evolution mechanism and law of subsurface damage layer in grinding DD5 with CBN wheel are discussed.It is found that recrystallization occurs in the deformed layer in the depth range of0-50 nm after high temperature heating,and the dislocation of the surface material is recovered.(2)The grinding performance(grinding force,grinding temperature)and workpiece surface quality(surface roughness,surface morphology,recrystallization layer)of different lubrication methods(dry grinding,pouring lubrication,texture wheel nano particle micro lubrication)were compared and analyzed.The results show that t-namql has the lowest grinding force;Compared with grinding temperature,t-namql has a good effect of reducing grinding heat;Compared with the surface roughness,t-namql has the smallest surface roughness,and t-namql reduces the recrystallization layer thickness of DD5 after heat treatment,and obtains better grinding surface quality.T-namql can significantly improve grinding performance of grinding wheel and grinding quality of workpiece.