Effect of annealing treatment on microstructure and tensile strength of alumina borate whisker-reinforced Al-Mg composite

The microstructures of alumina borate whisker reinforced Al-Mg composite, subjected to different annealing treatment, was studied using transmission electron microscopy. The characteristics of interfacial phases and the dislocation states in the matrix were investigated. The results indicated that the interfacial reaction between the whisker and the matrix in the composite cannot occur at 320 °C. The amount of interfacial phases reduces with the increase in annealing treatment time. The precipitation of Al₈Mg₅ at the whisker/matrix interface can dissolve into the matrix aluminum during annealing treatment. The dislocation states and the interfacial precipitation affect the tensile strength of the composite obviously, and the suitable annealing treatment process can be found for the ultimate tensile strength.