Abstract
Al2O3/TiC nanocomposites containing 5, 25 volume fraction of TiC were fabricated by pressureless sintering (PLS) technique. Al2O3/TiC mixtures consisted of 0.2μm-Al2O3, 0.2μm-TiC and sintering aids, which were mixed by ball-milling with ethanol for 24 hours. Al2O3/TiC-compacts were densified by pressureless sintering at 1500°to 1700°C in Ar atmosphere with hot isostatic pressing (post-HIP) at 1500°C under Ar pressure of 147 MPa. Al2O3/TiC nanocomposites had the microstructures, in which TiC partcles were dispersed mainly within Al2O3 grains, and showed the fracture strength of 1200 MPa and the fracture toughness of 4.3 MPa⋅m1/2. Also, Al2O3/TiC nanocomposites were approximately equal to those of hot pressing (HP). The improvement in high temperature hardness must be due to the pinning of dislocation and to the prohibitation of the grain boundary sliding by the nanosize TiC dispersion within Al2O3 matrix grains.
