Fabrication and mechanical properties of 5 vol% copper dispersed alumina nanocomposite

An optimum route to fabricate the Al2O3/Cu nanocomposite with sound microstructure and desired mechanical properties was investigated. Two methods for developing a uniform dispersion of Cu particles in Al2O3 were compared on the basis of the resulting microstructures and mechanical properties. SEM and TEM analyses for the composites fabricated by reduction and sintering process using Al2O3/CuO powder mixture showed that the nanosized Cu particles were well distributed and situated on the grain boundaries of the Al2O3 matrix. The composite, hot-pressed at 1450 degrees C, exhibited the maximum fracture strength and enhanced roughness compared with monolithic Al2O3. The strengthening was mainly attributed to the refinement of Al2O3 matrix grains. The toughening mechanism in Al2O3/Cu composite was discussed by the observed microstructural features and theoretical predictions based on crack bridging model and thermal residual stress effect. Published by Elsevier Science Limited.