Preparation and characterization of Al2O3–Ti3SiC2 composites and its functionally graded materials

Alumina/titanium silicon carbide (Al2O3–Ti3SiC2) composites and its functionally graded materials (FGMs) were fabricated by a powder metallurgy processes and their microstructure and properties were investigated, respectively. The experimental results showed that the Vickers hardness of composites decreased with increasing Ti3SiC2 content while the fracture toughness and strength exhibited the opposite trend. Minimum Vickers hardness (4 GPa), maximum strength (598 MPa) and maximum toughness (11.24 MPa m1/2) were reached in the pure Ti3SiC2 material. Strength and hardness of FGMs were evaluated. Observation using an scanning electron microscope (SEM) indicated that the presence of Ti3SiC2 of FGMs inhibited the growth of alumina grains through a pinning mechanism. The study shows that the combination of the layered Ti3SiC2 structure and the fine alumina grains can result in a Al2O3–Ti3SiC2 composites possessing a high toughness and low Vickers hardness without a sacrifice in the strength.