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

Abstract

An optimum route to fabricate the Al 2O 3 Cu nano-composite with sound microstructure and desired mechanical properties was investigated. Two methods for developing a uniform dispersion of Cu particles in Al 2O 3 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 Al 2O 3 CuO powder mixture showed that the nano-sized Cu particles were well distributed and situated on the grain boundaries of the Al 2O 3 matrix. The composite, hot-pressed at 1450 °C, exhibited the maximum fracture strength and enhanced toughness compared with monolithic Al 2O 3. The strengthening was mainly attributed to the refinement of Al 2O 3 matrix grains. The toughening mechanism in Al 2O 3 Cu composite was discussed by the observed microstructural features and theoretical predictions based on crack bridging model and thermal residual stress effect.