摘要
采用激光区熔快速定向凝固技术制备出Al2O3/Er3Al5O12(EAG)共晶自生复合陶瓷,研究了不同激光扫描速率下材料的凝固组织特征及其演变规律,并对其力学性能和增韧机制进行了分析.结果表明:激光区熔Al2O3/EAG由连续的Al2O3和EAG两相组成,两相相互交错分布,形成均匀的三维网状结构;共晶间距细小,在0.2～2.1μm之间,并随着扫描速率的增加规律性地减小.在低的扫描速率下,微观组织呈现典型的层片状非规则共晶组织;当扫描速率增至800μm/s时,出现了胞状及EAG树枝晶.共晶陶瓷的硬度和断裂韧性分别为18.7GPa和2.45MPa.m1/2.微观组织高度细化以及裂纹扩展过程中沿两相界面偏转、分叉等机制提高了材料的韧性.
Directionally solidified Al2O3/Er3Al5O12（EAG） eutectic ceramic was prepared by laser zone remelting technique.The eutectic morphology and microstructure evolution investigated as a function of laser scanning rate.Moreover,the mechanical properties and toughening mechanisms were studied.The Al2O3/EAG eutectic ceramic consists of only two continuous phases of Al2O3 and EAG which interpenetrates with each other to form well-distributed three-dimensional network.The eutectic spacing is only around 0.2-2.1μm and reduces with the increase of scanning rate.At low scanning rate,the typical lamellar irregular eutectic structure is obtained.When the scanning rate reaches 800μm/s,the cellular or dendrite microstructure appears.The hardness and the fracture toughness at room temperature are measured to be 18.7GPa and 2.45MPa·m^1/2,respectively.The refined micro-structure,crack deflection at phase interface and crack branching contribute to the improved toughness.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2011年第8期841-846,共6页
Journal of Inorganic Materials
基金
国家自然科学基金(51002122,50772090)
陕西省自然科学基金(2010JQ6005)
航空科学基金(2010ZF53064)
西北工业大学基础研究基金(G9KY1016)
西北工业大学材料学院“新人新方向”(09XE0104-5)
凝固技术国家重点实验室自主课题(76-QP-2011)~~
关键词
氧化物共晶陶瓷
激光区熔
微观组织
断裂韧性
oxide eutectic ceramic
laser zone remelting
microstructure
fracture toughness
作者简介
邓杨芳（1986-），女，硕士研究生．E—mail：fang_nwpu@163．com
通讯作者：张军，教授．E-mail：zhjscott@nwpu．edu．cn
