PROCESSING AND PROPERTIES OF COPPER DISPERSED ALUMINA MATRIX NANOCOMPOSITES

An optimum route to fabricate Al2O3/Cu composites with sound microstru cture and desired mechanical properties was investigated The Al2O3 mat rix composites with Cu content of 2.5 to 10 vol.% were prepared by red uction and hot-pressing of Al2O3/CuO powder mixtures. Homogeneous micr ostructures with nanosized Cu dispersoids and improved fracture streng th of 820 MPa could be achieved in the composites with Cu content of 2 .5 and 5 vol. %. The influence of the Cu content upon the mechanical p roperties is discussed based on the observed microstructural character istics. The toughness increase is explained by crack bridging. The str engthening is mainly attributed to the refinement of Al2O3 matrix grai ns by the nano-sized Cu dispersion. (C) 1998 Acta Metallurgica Inc.