Influence of oxide based reinforcements in oxide-oxide ceramic matrix composites (CMCs)

Abstract

In comparison to other processes, powder metallurgy processing of alumina-based ceramic matrix composites (CMC) is considered a viable option. In this study, Alumina ceramic composites are developed by adding MgO, TiO2, and Fe2O3 as reinforcement particles. Reinforcement particles were added to the Alumina matrix at 0.25%, 0.5%, and 1.0% by weight. Each reinforcement is added individually to the matrix by varying percentages. Alumina with reinforcement is mixed properly using hand grinding. Blended powders were compacted using a hydraulic press to form the green compact. Green compacted samples were preheated and sintered in a box furnace at a temperature at 1600 °C for 5 h. Mechanical properties of the sintered samples taken into consideration such as density, Vickers hardness, fracture toughness and porosity level have been measured. SEM images of the samples were carried out to understand the reinforcement presence in the matrix. It is observed that the highest bulk density (3.881 g/cm3) was obtained for alumina samples when reinforced with 0.5% TiO2. The minimum porosity level was found to be 0.199% when alumina was reinforced with 1% Fe2O3. The highest Vickers microhardness value was obtained to be 41.96GPa for 0.25% of the Fe2O3 reinforced alumina sample. Alumina with 0.5% MgO reinforcement has the highest fracture toughness of 8.98 MPa/m1/2.