Study On Design And Fabrication Of Al₂O₃Matrix Ceramic Tools Based On Multi-Phase And Multi-scale

Aiming at the lower mechanical properties of alumina-based ceramic composite tool of the problem, based on multi-phase and multi-scale design ideas, according to the design principles of nano-composite ceramic tool materials, select sub-micron and nano-Al2O3SiC based add phase, Ni, Ti, MgO, Y2O3and CeO2added to assist with the application hot pressing process, developed a new multi-phase and multi-scale Al2O3based nano-composite ceramic tool materials. Systematic study of the relationship between group assignment than the sintering process, mechanical properties and microstructure between toughening mechanisms analyzed composite ceramic tool materials.Based on the idea of multi-phase and multi-scale material design and size of the component design, materials and physical analysis, chemical analysis, multivariate analysis of the scale toughening mechanism, grain growth and sintering process analysis and other analyzes eventually established a composite ceramic tool the components of the material composition and the amount of each component and the particle diameter ratio. Studied the dispersion mechanisms and principles of nanoparticle dispersion, analyzes the factors that influence the liquid dispersion effect of polyethylene glycol4000as dispersant selected by experimental methods, and to determine the amount added.Experimental study of the effect of sintering temperature, holding time, nano and sub-micron alumina content of SiC content on multi-phase and multi-scale Al2O3based nano-composite ceramic tool material mechanical properties and microstructure of mechanical properties. Successfully developed a multi-phase and multi-scale Al2O3based nano-composite ceramic tool materials AS15A10(content is10vol%Al2O3nano and submicron SiC content is15vol%) of its optimum sintering process of sintering temperature1600℃, sintering pressure30MPa and holding time30min, flexural strength AS15A10Vickers hardness and fracture toughness averages were763.51MPa,23.87GPa and6.451MPa·m1/2. Microstructure studies show that:composite ceramic tool material fracture mode from intergranular fracture into transgranular fracture, grain refinement effect of adding nano-phase and multi-scale material design to improve the density of the material is the material mechanics improve the performance of the main reasons.Study the diverse multi-scale nano-composite ceramic tool material Toughening mechanisms. Multi-scale particles can suppress the grain growth of the base particle, refine the grain effect, while residual stress, crack deflection and crack pinning toughening mechanism multiscale SiC particles and residual stress cracking mechanisms play a partial conversed toughening effect of nano-particles are formed within the crystal matrix particles in sub-boundaries played a role in inducing transgranular fracture.