Role of Microstructural Features in Toughness Improvement of Zirconia Toughened Alumina  

作　　者：Olaniyi Fakolujo Ali Merati Mariusz Bielawski Manon Bolduc Michel Nganbe Olaniyi Fakolujo;Ali Merati;Mariusz Bielawski;Manon Bolduc;Michel Nganbe(University of Ottawa, Ottawa, Canada;National Research Council Canada, NRC Aerospace, Ottawa, Canada;Defence R&D Canada (DRDC Valcartier), Quebec, Canada)

机构地区：[1]University of Ottawa, Ottawa, Canada [2]National Research Council Canada, NRC Aerospace, Ottawa, Canada [3]Defence R&D Canada (DRDC Valcartier), Quebec, Canada

出　　处：《Journal of Minerals and Materials Characterization and Engineering》2016年第1期87-102,共16页矿物质和材料特性和工程（英文）

摘　　要：Ceramics constitute an integral part of highly efficient armours due to their low density, high hardness, strength and stiffness. However, they lack toughness and multi-hit capability. Therefore, zirconia toughened alumina is investigated. The hardness is evaluated using Vickers, Knoop and instrumented indentations, while the fracture toughness is evaluated using the indentation technique and Charpy tests. The strength is evaluated using ring-on-ring, four point bend and drop weight tests. The Young’s modulus is evaluated using the unloading instrumented indentation curves. Microstructure, porosity and density are characterised using ultrasonic scanning, Archimedes principle, optical and scanning electron microscopy. Results show an indentation size effect on all mechanical properties. A substantial improvement in toughness is achieved through retardation of crack initiation by tetragonal-to-monoclinic phase transformation in zirconia particles, crack deviation thanks to appropriate grain structure, as well as energy absorption by densification due to remaining porosity. This improved toughness is expected to promote multi-hit capability.Ceramics constitute an integral part of highly efficient armours due to their low density, high hardness, strength and stiffness. However, they lack toughness and multi-hit capability. Therefore, zirconia toughened alumina is investigated. The hardness is evaluated using Vickers, Knoop and instrumented indentations, while the fracture toughness is evaluated using the indentation technique and Charpy tests. The strength is evaluated using ring-on-ring, four point bend and drop weight tests. The Young’s modulus is evaluated using the unloading instrumented indentation curves. Microstructure, porosity and density are characterised using ultrasonic scanning, Archimedes principle, optical and scanning electron microscopy. Results show an indentation size effect on all mechanical properties. A substantial improvement in toughness is achieved through retardation of crack initiation by tetragonal-to-monoclinic phase transformation in zirconia particles, crack deviation thanks to appropriate grain structure, as well as energy absorption by densification due to remaining porosity. This improved toughness is expected to promote multi-hit capability.

关 键 词：Zirconia Toughened Alumina Toughening Mechanisms Fracture Toughness Ballistic Performance and Multi-Hit Capability 

分 类 号：TG1[金属学及工艺—金属学]