摘要
通过在铝热剂中引入ZrO2与Y2O3混合粉末,借助燃烧合成及远离平衡态下的共晶生长,制备出以t-ZrO2纳微米纤维成排镶嵌于其上、长径比为12.0-15.0且具有不同生长取向的Al2O3棒晶为基体的Al2O3/YSZ共晶复合陶瓷。相比于定向凝固Al2O3/YSZ共晶复合陶瓷,因本试验具有的高共晶生长速率,导致Al2O3棒晶上的ZrO2正方相纳微米纤维平均尺寸及相间距均下降至150nm,使棒晶基体上的残余压应力高于定向凝固Al2O3/YSZ共晶复合陶瓷,从而在棒晶内高密度低能异相界面的支持下,复合陶瓷得以强化;同时,也正因高强度棒晶及高密度、大角度晶界的存在,在裂纹扩展中诱发棒晶裂纹桥接、拔出及α-Al2O3片晶摩擦互锁增韧机制,材料又得以明显韧化,其断裂韧度高出定向凝固共晶复合陶瓷172%-240%。
By introducing ZrO2 and Y2O3 mixed powder into the thermit and making use of combustion synthesis and eutectic growth faraway from the equilibrium state,Al2O3/YSZ eutectic composite ceramics composed of randomly-oriented rod-shaped Al2O3 grains were prepared,and within the rod-shaped grain aligned tZrO2 nano-micron fibers were embedded.Comparing with high-performance directionally solidified Al2O3/YSZ composite eutectics,the higher eutectic growth results in both the average size of tetragonal ZrO2 nanomicron fibers and inter-phase spacing decreasing to 150nm,making compressive residual stresses higher than directionally solidified Al2O3/YSZ composite eutectics,so the composite ceramics are reinforced by the supports of high-density low-energy hetero-phase interfaces in rod-shaped grains;meanwhile,crack-bridging and pull-out of rod-shaped grains as well as friction interlock effect of αAl2O3 platelet grains are initiated just from high-strength rod-shaped Al2O3 grains,high-density and high-angle boundaries between the rod-shaped grains,so the ceramics are also enhanced greatly in fracture toughness,higher 172%～240% than that of directionally solidified Al2O3/YSZ composite eutectics.
出处
《粉末冶金技术》
EI
CAS
CSCD
北大核心
2007年第5期323-328,共6页
Powder Metallurgy Technology
基金
国家自然科学基金资助项目(50672131)
军械工程学院科研基金项目(YJJXM05001)资助
关键词
Al2O3/YSZ复合陶瓷
燃烧合成
快速凝固
纳米晶结构
强韧化
Al2O3/YSZ composite ceramics
combustion synthesis
rapid solidification
nanocrystalline microstructure
strengthening and toughening
作者简介
赵忠民（1968-），男，副教授。E—mail：zhao_zhongmin@163．net
