超重力下燃烧合成大体积凝固态Al2O3/ZrO2（4Y）研究

通过在铝热剂中引入ZrO2(4Y)混合粉末,以超重力下燃烧合成方式,制备出Al2O3/ZrO2(4Y)自生复合陶瓷板材,并研究了复合陶瓷微观结构、生长机理与力学性能.XRD、SEM与EDS结果显示,Al2O3/32%ZrO2(4Y)复合陶瓷基体为亚微米t-ZrO2纤维成三角对称分布其上、取向各异的棒状共晶团,而Al2O3/37%ZrO2(4Y)复合陶瓷则以分布均匀的微米级t-ZrO2球晶为基体.Al2O3/32%ZrO2(4Y)复合陶瓷的强化归因于小尺寸共晶团边界及残余压应力增韧、相变增韧机制引发的高断裂韧性所致;同时,细小t-ZrO2球晶所具有的小尺寸缺陷及相变增韧与微裂纹增韧机制所引发的高断裂韧性也使Al2O3/37%ZrO2(4Y)复合陶瓷得以强化.

Large bulk solidified Al_2O_3/ZrO_2(4Y) prepared by combustion synthesis under high gravity

By introducing ZrO2(4Y)powder into the thermit,Al2O3/ZrO2(4Y)self-growing composite ceramic plates were prepared through combustion synthesis under high gravity. Microstructures and growth mechanism were characterized by XRD,SEM and EDS,and mechanical properties of the composite ceramics were investigated. The results show that Al2O3/32%ZrO2(4Y)composite ceramics contain rod-shaped α-Al2O3 colonies,and within the colony,fiber-like t-ZrO2 with submicron-meter size is orderly aligned in the triangular symmetry; Al2O3/37%ZrO2(4Y)composite ceramics are mainly made up of fine t-ZrO2 spherical grains with micrometer size. Al2O3/32%ZrO2(4Y)composite ceramics are reinforced due to thin inter-colony regions and high fracture toughness induced by compressive residual stress toughening and transformation toughening mechanisms. meanwhile,Al2O3/37%ZrO2(4Y)composite ceramics are reinforced due to small-size critical defect induced by fine t-ZrO2 spherical grains and high fracture toughness caused by the intensive coupled toughening mechanisms involving transformation toughening and micro-crack toughening.