激光区熔定向凝固Al_2O_3/Y_3Al_5O_(12)(YAG)共晶的组织与断裂韧性  

Microstructure and fracture toughness of directionally solidified Al_2O_3/Y_3Al_5O_(12)(YAG) eutectic by laser zone melting

作　　者：苏海军[1] 张军[1] 刘林[1] 傅恒志[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《材料科学与工艺》2007年第6期741-745,共5页Materials Science and Technology

基　　金：国家自然科学基金资助项目(50102004);航空基础科学基金资助项目(04G53048);高等学校博士点专项科研基金资助项目(20040699035);西北工业大学基础研究基金资助项目(NPU-FFR-W018101);西北工业大学英才培养计划资助项目

摘　　要：采用激光区熔高温度梯度快速定向凝固技术从熔体中直接制备Al2O3／Y3Al5O12（YAG）共晶自生复合陶瓷，以研究其在超高温度梯度（1．0×10^6K／m）下的快速凝固组织特征及与激光工艺参数的关系，并对其力学性质进行分析．研究结果表明：凝固组织强烈地受激光扫描速度与功率密度的影响，当二者匹配时，Al2O3相和Y3Al5O12（YAG）相呈现均匀一致，连续分布的层状耦合共晶结构，共晶间距细小（1～2μm），且随扫描速度的增大逐渐减小；所制备的Al2O3／Y3Al5O12（YAG）共晶陶瓷硬度高达19．5GPa，断裂韧性达到3．6MPa·m^1/2。Al2O3/Y3Al5O12（YAG） eutectic ceramic was prepared from melt by laser-zone-melting with directional solidification technique to study the relationship between the eutectic microstructure and the processing parameters, and its mechanical property was investigated as well. The analysis results show that the scanning rate and power density strongly affect the eutectic microstructure. With the processing parameters adjusted properly, the binary Al2O3/YAG has a uniform and homogeneous lamella microstructure, in which single-crystal Al2O3 and single-crystal YAG are three-dimensionally and continuously reticularly connected and finely coupled without grain boundaries, colonies and amorphous phases between interfaces. Eutectic spacing is only around 1 - 2 μm and is diminished with the scanning rate＇ s increasing. The maximum hardness reaches 19. 5 GPa and the fracture toughness at room temperature is attained for 3.6 MPa · m^1/2 by Vickers indentation method.

关 键 词：AL2O3 /Y3Al5O12(YAG) 共晶自生复合陶瓷 激光区熔 

分 类 号：TB332[一般工业技术—材料科学与工程] TF125.42[冶金工程—粉末冶金]