Effect of milling time on microstructural and mechanical properties of nano-Al2O3P/6061Al composites prepared by transient liquid-phase sintering

Abstract

In this study, 5 vol% Al2O3 nanoparticles reinforced 6061 Al matrix nanocomposite was prepared by mechanical alloying the corresponding powders followed by hot-pressing. The effect of the milling time on the morphology of powder as well as the microstructure and mechanical properties of resulting nanocomposites was studied. The result shows that the effect of the milling time on the mechanical properties of nanocomposites comes from its effect on the distribution of Al2O3 nanoparticles in Al matrix. The long milling time is required to uniformly disperse Al2O3 nanoparticles within Al grains, in order to obtain good mechanical properties. The nanocomposite made from the powder milled for 50 h exhibits a tensile strength of 602 MPa and an elongation to failure of 8.8%, which are higher than those ever reported for the similar materials. The higher mechanical properties are mainly attributed to Orowan strengthening, grain boundary strengthening, and high dislocation density.