Rapid solidification and fracture behavior of ternary metastable eutectic Al2O3/YAG/YSZ in situ composite ceramic
Rapid solidification and fracture behavior of ternary metastable eutectic Al2O3/YAG/YSZ in situ composite ceramic
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DOI：
10.1016/j.msea.2010.11.046
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发表时间：
2011-02
期刊：
影响因子：
6.4
通讯作者：
H. Su;Jun Zhang;Jianzheng Yu;Lin Liu;H. Fu
中科院分区：
文献类型：
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作者：
H. Su;Jun Zhang;Jianzheng Yu;Lin Liu;H. Fu
定向固化氧化物陶瓷共晶原位复合材料是一种很有前途的氧化环境高温结构材料。研究了激光区域重熔法制备的Al2O3/YAG/YSZ原位复合陶瓷三元亚稳共晶组分的快速凝固特性。采用维氏压痕技术研究了复合材料的断裂韧性和裂纹扩展行为。亚稳共晶Al2O3/YAG/YSZ陶瓷由Al2O3、YAG和YSZ相组成，呈现出典型的超细不规则层状微观结构，共晶间距可达0.5μm。此外，在非共晶成分处还形成了具有耦合生长特征的三元共晶组织，有效地扩大了共晶生长范围。亚稳共晶Al2O3/YAG/YSZ陶瓷的平均断裂韧性为3.9±1.0 mpam /2。zro2的加入削弱了YAG与al2o3相之间的界面结合，裂纹偏转、分支和微裂纹增韧是主要的增韧机制。
Directionally solidified oxide ceramic eutectic in situ composites are promising candidate materials for high-temperature structural applications in oxidizing environments. The rapid solidification characteristics of ternary metastable eutectic composition of Al2O3/YAG/YSZ in situ composite ceramics grown by laser zone-remelting technique are investigated. The fracture toughness and crack propagation behavior of the as-solidified composites are examined by the Vickers indentation technique. The metastable eutectic Al2O3/YAG/YSZ ceramic consists of Al2O3, YAG and YSZ phases, showing a typical ultra-fine irregular lamellar microstructure morphology with eutectic spacing as fine as 0.5μm. Moreover, the ternary eutectic microstructures with coupled growth characteristics are also formed at the off-eutectic composition, effectively enlarging the eutectic growth range. The mean fracture toughness of the metastable eutectic Al2O3/YAG/YSZ ceramic is 3.9±1.0MPam1/2. The addition of ZrO2which weakens the interface bonding between YAG and Al2O3phases, crack deflection, branching and microcrack toughening are the predominant toughening mechanisms.