Study and Analysis of Al2O3-SiC Nanocomposite Ceramics’ Fracture Toughness using Vickers Indenter

Abstract

The basic trait in the ceramics is their high brittle or low fracture toughness, and the main criteria in the design and application is specifying the fracture toughness in ceramics. In this paper, a new method is proposed to determine the fracture toughness of ceramics, which is enhanced in lowering the cost of fracture toughness determination relative to the previous methods. Hence due to the low cost and case of access of alumina (Al2O3) which is extensively used in ceramics industry, it is applied as the most important source for achieving the objectives. Pure alumina has excellent properties such as refractory and high hardness on one hand, and has disadvantages such as low fracture toughness on the other hand. In order to improve its mechanical properties, various additives such as nano scale silicon carbide (SiC) powder are used. In this paper, alumina micro powder having 5% nano magnesium oxide by weight were mixed separately with silicon carbide nano particles of 2.5%, 5%, 7.5%, 10% and 15% to construct various types of ceramics, with different physical and mechanical properties. Semi experimental equation for their fracture toughness determination was presented and used for other brittle materials. This equation has minimal cost of experiments for determining fracture toughness of different brittle materials.