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 Al₂Os 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°C, exhibited the maximum fracture strength and enhanced toughness 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.