Al_2O_3/ZrO_2(3Y)快速凝固共晶复合陶瓷显微结构、裂纹桥接与增韧  

Microstructures,Crack-Bridging and Toughening of Al_2O_3/ZrO_2(3Y) Rapidly-Solidified Eutectic Composite Ceramics

作　　者：张龙[1] 赵忠民[1] 吴江[1] 潘传增[1] 张靖[1] 

机构地区：[1]军械工程学院先进材料研究所,河北石家庄050003

出　　处：《稀有金属材料与工程》2007年第A01期647-650,共4页Rare Metal Materials and Engineering

基　　金：国家自然科学基金项目资助(50672131)

摘　　要：通过在铝热剂中添加适量的ZrO(23Y)粉末,借助燃烧合成及远离平衡态下的快速凝固方式,制备出Al2O3/ZrO2(3Y)共晶复合陶瓷。XRD,SEM与EPMA分析得出,陶瓷基体是由t-ZrO2纳微米纤维镶嵌于其上、长径比为10.0～14.0且呈随机生长的氧化铝棒晶及少量的α-Al2O3片晶构成。结合裂纹扩展路径与棒晶内部结构,可认为因共晶凝固所形成的、存在于蓝宝石棒晶上的高密度异相界面及因共晶两相热膨胀失配所诱发的高残余压应力,蓝宝石棒晶得以强化,因而陶瓷的主要增韧机制来自因蓝宝石棒晶裂纹桥接所产生的内部弹性应变能释放及因高能、大角度晶界解离所诱发的能量消耗,并伴随着因片晶摩擦互锁效应所造成的能量耗散过程。By adding ZrO2 （3Y） powder of suitable content into the thermit, and by means of combustion synthesis and rapid solidification process far away from the equilibrium state, Al2O3/ZrO2 （3Y） eutectic composite ceramics have been prepared. XRD, SEM and EPMA results indicate that the composite ceramics is composed of the randomly-oriented rod-shaped grains in the majority and α-Al2O3 platelet grains, and within the rod-shaped grains t-ZrO2 aligned nano-micron fibers are embedded. Combining crack propagation paths and microstructures of rod-shaped grains, it is concluded that high-density low-energy heterophase interfaces between Al2O3/ZrO2 phases established during eutectic solidification and high compressive residual stresses due to thermal expansion mismatch of Al2O3/ZrO2 phases make the rod-shaped grains reinforced, whereupon this reason the major toughening mechanisms are the release of strain energy stored in the rod-shaped grains, the consumption of fracture energy in creating the debonded interfaces and the dissipation of fracture energy in forming frictionally interlocked α-Al2O3 platelet grains.

关 键 词：燃烧合成 快速凝固 Al2O3/ZrO2(Y2O3)共晶复合陶瓷 纳米晶结构 裂纹桥接 增韧 

分 类 号：TQ174.1[化学工程—陶瓷工业]