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0.2~2.1 μm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800μ m/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.
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