SHS纳米/微米块体复相陶瓷微观结构与断裂

通过在(CrO3 Al)燃烧体系中添加一定量的ZrO2(2Y)粉末,利用SHS冶金技术直接制备出Al2O3-35vol%ZrO2纳米/微米结构块体复相陶瓷,研究该复相陶瓷的微观结构与断裂行为.研究发现:该复相陶瓷基体主要由纳米/微米相晶内型结构共晶体组织构成;Vickers压痕试验显示引发陶瓷裂纹扩展的压痕压制临界载荷为30 kg;ZrO2相所具有的应力诱发相变增韧机制和微裂纹增韧机制均很微弱;裂纹扩展主要受纳米/微米相晶内型结构共晶体控制,使该复相陶瓷在断裂过程中呈现出强烈的裂纹偏转绕过机制.

Microstructures and fracture of nano-micron bulk multiphase ceramics fabricated by the SHS metallurgical process

By adding ZrO_2(2Y) powder of certain content into (CrO_3+Al) combustion system, bulk nano-micron structured multiphase ceramics of Al_2O_3-35vol%ZrO_2 was obtained in one quick step through the SHS metallurgical process, and mirostructures and fracture behaviors of the multiphase ceramics were also investigated. Experimental results showed that the ceramics was mainly composed of the eutecticums of intro-granular structures with nano-micron ZrO_2 fibers, Vickers indentation tests indicated that the critical value of indentation load which induced crack of the ceramics to extend was 30kg, and XRD quantitative analyses demonstrated stress inducedtransformation toughening mechanism and micro-crack toughening mechanism owned by ZrO_2phases were executed very poorly. SEM observation showed crack extension was mainly controlled by the eutecticums of intro-granular structures with nano-micron ZrO_2 phases, resulting in existence of strong toughening mechanism due to crack deflection during fracture process of the ceramics.