摘要
通过在燃烧合成过程中引入超重力,可以制备出大尺寸、低缺陷的Al2O3/ZrO2(4Y)共晶复合陶瓷板。XRD表明,超重力并不改变陶瓷的物相组成,其基体均由α-Al2O3、t-ZrO2与m-ZrO2组成;SEM分析显示,随着超重力的增大,镶嵌有t-ZrO2纤维的共晶团发生胞状组织向棒状组织的转化,且共晶团体积分数与长径比逐渐增大;力学性能测试表明,复合陶瓷相对密度、硬度与断裂韧度随超重力增大而增大,至225g(重力加速度)时均达到最高值,分别为97.8%、18.7GPa与15.6MPa.m1/2;并且,陶瓷的高断裂韧度是因棒状共晶团的裂纹偏转与桥接增韧及处于共晶团边界上的t-ZrO2微米球晶的相变增韧与微裂纹增韧机制所致。
By introducing high gravity into combustion synthesis,the Al2O3/ZrO2 (4Y) eutectic composite ceramic large bulk plates were prepared. The XRD analysis shows that the ceramic plates are composed of α-Al2O3,t-Al2O3 and m-ZrO2 phase under high gravity. SEM observation reveals that with increasing in high gravity,eutectic colony embedded by t-Al2O3 fiber is transformed from cellular structure into rod-like one,in which volumetric fraction and length-diameter ratio of eutectic colony are increased gradually. Relative density,the Vickers hardness and fracture toughness of the composite ceramics are increased with increasing in high gravity,and maximum values reach 97.8%,18.7GPa and 15.6MPa·m1/2,respectively,at 225g. High fracture toughness of the ceramics is attributed to the coupled effects of crack-deflection and crack-bridging toughening by rod-like eutectic colony with transformation toughening and micro-crack toughening by the fine spherically-shaped tetragonal ZrO2 crystals at inter-colony regions.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2009年第9期841-844,共4页
Special Casting & Nonferrous Alloys
基金
国家自然科学基金资助项目(50672131)
