Research On Integrated Manufacturing Technology And Cutting Performance Of Indexable SiAlON Ceramic End Mill Inserts

Superalloy is a necessary metal material in modern aerospace,nuclear industry and chemical industry.However,superalloy is a typical difficult-to-machine material.When using traditional tools to process superalloy,the tool wear is serious and the cutting force is large.Due to the high processing efficiency and good processing quality of ceramic tools,more cutting-edge research focuses on ceramic tools for cutting high-temperature alloys.Based on microwave sintering technology,this paper studies theβ-Sialon ceramic material component system with appropriate Z value,designs the edge shape of the end milling insert suitable for high-speed milling of high-temperature alloys,and finally prepares theβ-Sialon ceramic end mill with good cutting performance.blade.The density and mechanical properties of β-Sialon ceramic materials were improved by orthogonal experiment and the combination of different sintering aids,and the optimal sintering aid system was determined,5wt%Y₂O₃+0.5wt%Yb₂O₃.At this time,β-Sialon ceramic tool material had the best mechanical properties.Its density was 3.23 g/cm³,Vickers hardness was 14.30±0.23GPa,and fracture toughness was 7.28±0.73 MPa·m^1/2.Based on the optimized sintering aids,the performance changes of β-Sialon ceramic materials with different Z values were studied.Its density and mechanical properties both got the maximum when Z=1.5,and got the minimum when Z=2.1.The change of the Z value changed the ratio of Si₃N₄and Al₂O₃in the original composition,and also changed the ease ofβ-Sialon densification in microwave sintering.At the same time,the oxide raw material Al₂O₃and the sintering aid generated a large amount of liquid phase,and reduced the viscosity of the phase.It promoted the solubility of Si₃N₄during the sintering process,so that the densification was completely carried out.The crystal grains were mostly prismatic,with an aspect ratio of 2.1-4.5.The high aspect ratio grains could effectively prevent the pulling out of the grains,thus greatly improved the fracture toughness ofβ-Sialon.The simulation study the influence of tool structure parameters（rake angle,relief angle,tool nose arc radius）and milling quantity（milling speed,feed per tooth and back-cutting）on??milling force and milling temperature.Research showed that when the rake angle of the tool is-5°,the tool temperature was the smallest and the cutting force was smaller.At the same time,as the tool clearance angle increases,the clearance angle fluctuated at 1000°C,the Fy direction milling force and the Fz direction milling force were gradually decreasing,and the milling force in the Fx direction showed a trend of first increasing and then decreasing,so the tool clearance angle is 9°.Although the milling force in the three directions of the 0.4mm tool nose arc radius was the smallest,the arc radius of the tool tip was too small and the strength of the cutting edge was weakened,so the selected arc radius was 0.8mm.Under the optimized tool structure parameters,through orthogonal experiment and comprehensive balance method,Smaller feed per tooth is beneficial to the temperature,larger milling speed results in a higher milling temperature,and larger back-grabbing will result in a larger milling force.The milling experiment researched the cutting performance and failure mechanism ofβ-Sialon ceramic tool end milling insert and round insert milling nickel-based superalloy.Using orthogonal experiments,it was found thatβ-Sialon ceramic end milling inserts were suitable for low-speed and small depth of cut（v_c=50m/min,f_z=0.1mm/z,a_p=0.1mm）for milling nickel-based superalloys,and the most important milling parameter that affects cutting performance was cutting speed.The main forms of wear were tool tip wear,surface spalling,abrasive wear and chipping.The best milling parameters for high-speed milling of nickel-based superalloys withβ-Sialon ceramic round inserts were=v_c800m/min,f_z=0.05mm/z,a_p=1mm.The main forms of wear were abrasive wear,bond wear,oxidative wear,Diffusion wear,accompanied by chipping and chipping of the cutter body.And compared with the performance of commercial coated carbide tools at the same milling efficiency,the study showed that the metal removal ofβ-Sialon ceramic tools was 5 times that of coated carbide tools.