Abstract
Mechanical properties and microstructure of Al2O3/W composites have been investigated. These composites were fabricated by hot-pressing the mixture of γ - or α-types of alumina(Al2O3) and fine tungsten(W) powders. In these composites, the fine W particles were located both within Al2O3 matrix grains and at grain boundaries. The fracture strength of Al2O3/5vol%W composites sintered at 1400°C was 700MPa, which is approximately 1.6 times higher than that of the monolithic Al2O3 that prepared under the same conditions. But the strength decreased with increasing sintering temperature. Although the interactions between clacks and W dispersions were partly observed, the fracture toughness was not significantly enhanced. It is supposed that the effects of nano-structure did not sufficiently act on the mechanical properties of the composites because the grain boundary of Al2O3, where large W particles are located, was not strengthened by the dispersions.
