Research On Microwave Sintering And Cutting Performance Of Multi-scale Particle Composite Al₂O₃ Based Ceramic Tools

In this paper,the production process and performance characterization of multi-scale alumina-based composite ceramic tool material were studied.A new type of alumina-based ceramic tool material,Al2O3?-TiC?-TiCn-Co-Ni-Mo,was developed and the thermal shock resistance of the material was studied by thermal shock test.The cutting performance of the material was studied by cutting experiments.Through the study of the process of traditional subsiding experiment,a new experimental scheme was designed,and the best acid-base degree was 9.5 while the content of PEG was 0.5wt%of the nanoscale titanium carbide powder.In view of the shortcomings of traditional ball milling process,a new powder mixing experimental scheme with ultrasonic and seal agitation is designed,which shorten the production cycle remarkably.Through the analysis of the principle of the heat keeping device used in microwave sintering,a new type is designed,which improves the thermal insulation performance of the device greatly and prolongs the service life of heat insulating material greatly.The best sintering process is determined by stacking experiments.By studying the distribution of the surface properties of ceramic sample,a more reasonable material performance characterization plan has been determined.By studying the mechanical properties and microstructure of the ceramic tool material samples,the optimum metal phase content,composition and the addition amount of nanoscale titanium carbide were determined in turn.Then a kind of ATT ceramic tool materials with the relative density of 97.75%,the Vicker's hardness of 17.664GPa and the fracture toughness of 6.610MPa· m1/2 was obtained.Through a single thermal shock experiment,the critical thermal shock temperature difference of ATT ceramic tool material was determined to be about 150?.Through cyclic thermal shock experiment,the indentation crack forms of the material was determined as crack deflection,intergranular fracture,transgranular fracture,grain bridging,grain extraction and fracture bifurcation.The cutting performance of ATT ceramic tool material was studied by continuous dry cutting of 40Cr steel.It has better cutting quality and longer tool life when the cutting speed is 180m/min,the feed rate is 0.10mm/r and the depth of cut is 0.1mm,the wear mechanism was abrasive wear and cohesive wear.By comparing with the CVD coated carbide tool YBC251,the conclusion that ceramic tool ATT is more suitable for high speed continuous turning stainless steels 40Cr is obtained.