Research On Cutting Mechanism Of High Speed Cutting GH4169 Based On Multi-scale Simulation

GH4169 is a nickel-based superalloy strengthened by body centered tetragonal?''and face centered cubic?'precipitation,which have a high yield strength,high corrosion resistance and high temperature oxidation resistance.Alloying elements exist in the form of high hardness compounds,such as TiC,NbC and other interphase hard point.The presence of these high-hardness compounds leads to complex cutting deformation during cutting,high cutting temperatures,large cutting force and large fluctuations,severe tool wear and residual stress,etc.,which in turn makes surface quality difficult to guarantee.Since the material properties and failure criteria of the hard particles in GH4169 material are different from those of the matrix material,the size,shape,and distribution of the particles are random.Therefore,the traditional single-scale metal cutting simulation model is no longer suitable for the study of GH4169.The multi-scale finite element model of GH4169 was established by adding brittle phase particles containing cohesive elements to the cutting model.The accuracy of the model with and without brittle phase particles was verified from two aspects of chip morphology and cutting force.Compared with the finite element cutting simulation model without the brittle phase,the chip morphology,cutting force magnitude,and fluctuation after adding the brittle phase particles are more similar to the experimental results.The multi-scale model was used to further study the effect of brittle on jagged chip morphology and the mechanism of brittleness relative to dislocation slip of matrix grains.The wear characteristics of carbide cutting tools in the process of cutting GH4169 are studied.The wear mechanism of the tool is revealed.The main wear patterns of the wear debris from the tool body are given.The cracks in the tool during the cutting process are thoroughly studied and the mechanism of tool wear evolution is finally induced.Aiming at the presence of hard spots in nickel-based superalloys,which leads to residual stresses in the machining process,resulting in unsatisfactory surface quality,in-depth study of the formation mechanism and distribution of residual tensile/compressive stress on the machined surface,and the brittle phase The effect of size and position on residual stress.The results show that the multi-scale simulation model with the addition of the brittle phase can more accurately reveal the cutting deformation,the tool wear mechanism,and the distribution law and characteristics of the residual stress in the high-speed cutting GH4169 process.The research results can provide theoretical basis and reference for further study of GH4169 cutting performance and improved surface quality.