烧结温度对20%ZrO_2(3Y)/Al_2O_3复相陶瓷力学性能和微观结构的影响

20%纳米ZrO2(3Y)粉末加入到高纯亚微米Al2O3粉中,采用高压干压成型方法和恒速升温多阶段短保温烧结方法制备出不同烧结温度下的复相陶瓷。研究烧结温度对复相陶瓷力学性能的影响,通过XRD,EDS和SEM对复相陶瓷进行元素组成和微观结构分析。结果表明:烧结温度在很大程度上影响着复相陶瓷的力学性能和微观结构,常压烧结1600℃保温8h时,相对密度、维氏硬度和断裂韧性达到最大,分别为98.6%,18.54GPa和9.3MPa·m1/2,而基体晶粒尺寸为1.4~8.1μm,ZrO2相变量为34.6%。1600℃下复相陶瓷具有优质的微观结构,断裂方式为沿晶-穿晶混合断裂模式。ZrO2(3Y)粉体的加入,从相变增韧、内晶型颗粒增韧和裂纹偏转等多个方面提高了复相陶瓷的断裂韧性。

Effects of Sintering Temperature on Mechanical Properties and Microstructure of 20%ZrO2 (3Y)/Al2 O3 Composite Ceramics

20% nano ZrO2 (3Y)powders were added to high purity submicron Al2 O3 powders,then composite ceramics were prepared by high-pressure dry pressing and constant heating,multi-stage, short insulation sintering method at different temperatures.The effect of sintering temperature on mechanical properties of composite ceramics was investigated,the phase composition and microstruc-ture of composite ceramics were analyzed by XRD,EDS and SEM.The results show that the sintering temperature affects the mechanical properties and microstructure of composite ceramics greatly.The relative density,vickers hardness and fracture toughness reach the maximum value,respectively 98.6%,18.54GPa and 9.3MPa·m1/2 under atmospheric sintering at 1600℃ and insulation 8h.While the grain size of the matrix is about 1.4-8.1μm and ZrO2 phase transition is 34.6%.Composite ceram-ics have excellent microstructure sintered at 1600℃.The fracture mode of the composite ceramics is intergranular-transgranular mixed fracture mode.The fracture toughness of the composite ceramics is improved by phase transition toughening,intragranular particles toughening,crack deflection and other aspects when adding nano-sized ZrO2 (3Y)powder.