The Mechanical properties and microstructure of Al
2O
3/ W composites have been investigated. These composites were fabricated by hot-pressing a mixture of γ
- or α
- phase alumina (Al
2O
3) and fine tungsten (W) powders. In these composites, fine W particles were located both within the Al
2O
3 matrix grains and at the grain boundaries. The fracture strength of Al
2O
3/5vol%W composites sintered at 1400ºC was 700 MPa, which is approximately 1.6 times higher than that of monolithic-Al
2O
3 prepared by way of the same processing method. But, the strength decreased with an increase in the sintering temperature. Although the interactions between cracks and W dispersion were partly observed, the fracture toughness was not significantly enhanced. It is believed that the presence of nanostructures do not sufficiently act on the mechanical properties of the composites because the grain boundary of the Al
2O
3 matrix where large W particles are located is not significantly strengthened by dispersion.
† This report was originally printed in Journal of the Japan Society of Powder and Powder Metallurgy, 38(3), 326-330 (1991) in Japanese, before being translated into English by KONA Editorial Committee with the permission of the editorial committee of Japan Society of Powder and Powder Metallurgy.
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