Effect of the interfacial reaction of aluminum and yttrium oxide on aging behavior of aluminum-magnesium-silicon alloy reinforced with yttrium oxide modified sub-micron alumina

Age-strengthening behavior of Al-Mg-Si alloy composites reinforced with sub-micron alumina particles modified by yttrium oxide under the temperature of 130 °C, 160 °C and 190 °C was investigated. The mechanical performances of unmodified and modified composites after the aging treatment were evaluated with the tensile test. The results indicate that the hardness level of modified composites is obviously increased compared to unmodified composites at different aging states, and the process of aging precipitation of the matrix alloy in modified composites is accelerated by the interfacial reaction of aluminum and yttrium oxide. The aging microstructures of modified composites have a significant difference compared to non-modified composites, and present a large amount of dislocations and precipitates in the matrix alloy. The modified composites treated by the aging exhibit excellent tensile properties. It is suggested that the interfacial reaction resulted from the surface modification of particles with the rare-earth yttrium oxide is beneficial in promoting the process of aging precipitates and strengthening the aging microstructures and properties of Al alloy matrix in modified composites.