Characterization of Al2O3 Based CMC Reinforced with ZrO2 Particles Fabricated by Powder Metallurgy Technique

Abstract

This study evaluates the effect of addition of 3 mol% yttria-stabilized zirconia (3Y-TZP) in amounts of 5, 10, 15, and 20 wt.% on microstructure and phase evolution, densification behavior, and mechanical properties of alumina-based ceramic matrix composites. Composite specimens were fabricated using powder metallurgy techniques via uniaxial compaction and sintering at temperatures of 1500°C, 1550°C, 1600°C, and 1650°C for a dwell time of 2-hour. Phase composition and microstructural characteristics were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM), while densification behavior was evaluated through Archimedes’ principle. Mechanical performance was assessed using flexural strength, fracture toughness, and Vickers hardness tests. The results indicated that higher sintering temperatures promoted densification effect through vacancy diffusion and pore elimination. While the addition of zirconia restrained alumina grain coarsening through pinning of grain boundary migration, causing the composite having 20 wt.% zirconia to exhibit the highest relative density of about 97.5% when sintered at 1600°C. Mechanical properties improved progressively with increasing zirconia content up to 15 wt.%, where flexural strength reached about 438 MPa, fracture toughness increased to about 6.6 MPa·m½, and Vickers hardness of about 1770 HV, corresponding to enhancement percentages of about 20.5%, 41%, and 4.5%, respectively.