Effect of interfacial reaction on tensile and creep behaviors of aluminum-borate-whisker-reinforced AA6061 composite

Aluminum-borate (AlBO) whisker-reinforced AA6061 composite fabricated by squeeze casting was subjected to both tensile and creep investigations. The whisker exhibited a significant reinforcing effect on as-extruded AA6061, but not for T6-treated specimen. The yield strength of the composite decreased slightly after T6 treatment. This was caused by the degradation of the whiskers and the microcrack initiation. The incorporation of the AlBO whisker into the AA6061 improved the creep resistance of the alloy by several orders of magnitude. Moreover, the composite exhibited higher values of apparent stress exponent and apparent activation energy for both the static and cyclic creep. Finally, cyclic creep retardation behavior was observed for both reinforced and unreinforced AA6061.