Development Of Ceramic Fiber Reinforced Laminated Cermet Cutting Tools

To solve the problem of the low hardness and low wear resistance of cermet tool materials,this paper uses(Ti,W)C as the matrix of laminated cermet tool materials,adding ceramic fibers to the middle layer of the laminated cermet tool,and use Spark plasma sintering(SPS)prepared laminated cermet cutting tools.Due to the different thermal expansion coefficients of each layer of laminated cermet tools,residual compressive stress will be generated on the surface of the tool after sintering,which improves the hardness of the tool and enhances the wear resistance of the tool.The spark plasma sintering method was used to prepare(Ti,W)C cermet tool materials.The effects of spark plasma sintering on the mechanical properties,microstructure and grain size of(Ti,W)C cermet tool materials under different sintering parameters are studied.The results show that when the sintering temperature is1400°C,the holding time is 10 min,and the sintering pressure is 30 MPa,the(Ti,W)C cermet tool material has the best mechanical properties and microstructure.The Vickers hardness of the cermet tool material is 20.28±0.67 GPa,the fracture toughness is 7.74±0.56 MPa·m^1/2,and the bending strength is 796.1±40.55 MPa.Ceramic fiber(Al₂O₃ceramic fiber)was added to the middle layer of laminated cermet tool material,a laminated cermet tool material was designed,and the physical model of laminated cermet tool material was established by finite element method(FEM).The influence of factors such as the composition content and thickness of the ceramic fiber in the intermediate layer on the residual stress is simulated by the finite element method.(Ti,W)C/((Ti,W)C+Al₂O₃ceramic fiber)laminated cermet tool materials were prepared by spark plasma sintering.The results show that when the Al₂O₃ceramic fiber content of the intermediate layer is 5 vol.%and the thickness of the intermediate layer is 1 mm,the overall mechanical properties of the material are optimal.The residual compressive stress of the surface layer is-71.14 MPa,which is consistent with the design results.Compared with homogeneous tool materials,the bending strength of laminated cermet tool materials is 1005.1±50.55 MPa,the fracture toughness is 8.25±0.26 MPa·m^1/2,and the surface hardness is 21.07±0.46GPa,an increase of 26.26%,6.6%and 3.9%,respectively.Single factor test was used to test 40Cr under different cutting parameters,and the best cutting parameters were determined.The effect of adding ceramic fibers on the cutting performance of laminated cermet tools is analyzed.The results show that the addition of ceramic fibers causes residual stress on the surface of the laminated cermet tool,and the cutting force during the cutting process is smaller than that of a homogeneous tool;And due to the reduction of the cutting force of the laminated cermet tool,the cutting temperature of the laminated cermet tool and the surface roughness of the processed workpiece are improved.It can be seen from the wear morphology of the rake and flank surfaces of the tool that homogeneous cermet tools are more severely worn than laminated cermet tools.The residual compressive stress formed on the surface of laminated cermet tools is conducive to the cutting performance.Compared with homogeneous cermet tools,the cutting distance of laminated cermet tools is significantly improved.