A thesis submitted to The Universiti Teknologi Brunei (UTB) in partial fulfillment of the requirements for the degree of Master of Science (MSc) in Mechanical Engineering. ABSTRACT Polymer infiltrated zirconia network (PIZN) is a hybrid material containing a sintered ceramic matrix infiltrated with a polymeric material. It is a machinable computer aided design/computer aided manufacturing (CAD/CAM) material that has been recently introduced for applications in engineering and dentistry. During the CAD/CAM fabrication process, the induced damage is inevitable, degrading its mechanical properties and shortening its in-service survival. Therefore, it is very vital to minimize the induced damage during fabrication of PIZN, requiring the understanding and knowledge of its mechanical behavior. For this purpose, the mechanical behaviour of PIZN at different polymer contents and sintering temperatures is investigated. Elastic modulus, fracture toughness and Vickers hardness are extracted by conventional mechanical tests. Advanced mechanical properties are characterized by plastic deformation resistance, elastic and plastic deformation components and brittle index. Increasing the polymer content from 0 to 42% leads to the corresponding decrease in elastic modulus, hardness, and fracture toughness. With the increase in sintering temperature, the elastic modulus and the hardness increase which usefully explain the densification process at higher sintering temperatures. However, the fracture toughness initially increases but decreases at higher temperature. Mechanical properties and polymer content are well related by empirical relations in literature. Plastic deformation resistance and component and brittleness index confirm better plastic properties for PIZN at 26-42% contents and 1100 "C sintering temperature. Therefore, it is recommended to process PIZN with not-lower- than 26% polymer content at 1100 °C in order to utilize its plastic properties during the CAD/CAM process for improved efficiency and quality.
Thesis (Degree) -Universiti Teknologi Brunei, 2022.