原位生长纳微米纤维自增韧复相陶瓷显微结构与不同尺度多级增韧  

Microstructures and Different-scale Multistage Toughening of Self-toughening Composite Ceramics with In-situ Growing Nano-micron Fibers

作　　者：赵忠民[1] 张龙[1] 白鸿柏[2] 许宝才[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 [2]军械工程学院振动与冲击防护研究所,河北石家庄050003

出　　处：《稀有金属材料与工程》2006年第A02期91-95,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金项目(59972043);军械工程学院科研基金项目(YJJXM05001)

摘　　要：通过将ZrO2微米粉末引入铝热剂中,借助铝热燃烧、陶瓷／金属液相分离及共晶反应中的晶体原位生长,制备出原位生长纳微米纤维自增韧Al2O3／ZrO2陶瓷复合材料。研究表明,陶瓷基体主要由以单晶t-ZrO2纳微米纤维为第二相、单晶α-Al2O3为基体且长径比为8．0～16的棒晶构成,并且在棒晶边界上还分布着α-Al2O3片晶、ZrO2微米粒子及Cr金属颗粒。力学性能测试得出,陶瓷的弯曲强度、弹性模量及断裂韧性分别达到1168MPa、410GPa与12．6 MPa·m0.5;裂纹扩展路径观察发现,陶瓷增韧是通过裂纹偏转增韧、纳微米纤维增韧、α-Al2O3片晶的裂纹桥接增韧、延性相增韧及应力诱发相变增韧不同尺度四级增韧机制的协同作用予以实现。By introducing ZrO2 micron powder into the thermit and through thermit combustion, liquid-liquid separation of metal/ceramics and crystal in-situ growth ofeutectic reaction, self-toughening composite ceramics with in-situ growing nano-micron fibers were fabricated. It is found that the ceramics were mainly composed of rod-shaped crystals with aspect ratio of 8.0-16, which monocrystalline t-ZrO2 nano-micron fibers were embedded in monocrystalline α-Al2O3 matrix; in addition, platelet like α-Al2O3 crystal, ZrO2 micron particles and Cr metallic particles were also found at the boundaries of rod-shaped crystals. Meanwhile, Flexural strength, elastic modulus and fracture toughness of the ceramics reached 1168 MPa, 410GPa and 12.6 MPa·m^0.5, respectively. It is further found from the observation of crack extension paths that this procedure for toughening ceramics is dependent on coordinated action of different-scale four-stage toughening mechanisms involving deflection-induced toughening, nano-micron fibers toughening, crack-bridging toughening by platelet like α-Al2O3 crystals, toughening ceramic matrix by ductile phases and stress-induced transformation toughening.

关 键 词：Al2O3/ZrO2陶瓷复合材料 纳微米纤维 原位生长 增韧 

分 类 号：TB383.1[一般工业技术—材料科学与工程]