Processing and mechanical properties of Mg-2.8Al-0.8Zn alloy containing bimodal size distribution

Abstract

The effect of bimodal size(nano + micron) distribution on the microstructure and mechanical properties of Mg-2.8Al-0.8Zn(AZ31B) fabricated by ultrasonic dispersion method was discussed. The grain refinement-degrees of composites not only connect with double size distribution, but also with the proportion of double size distribution. Compared to other samples, microstructural characterizations of AZ31B alloy containing (4.0%micron+1.0%nano)SiC revealed presence of uniformly distributed micro-SiC(SiCMP) hybridized with nano-SiC(SiCNP) and reduction in average matrix grain size. At room temperature, tensile tests results showed a superior combination of strength and ductility for Mg-(4.0SiCMP+1.0%SiCNP) composite compared with other composites. The reasons are mainly attributed to the presence of double size distribution, the lowest level of agglomeration of SiCMP hybridized with SiCNP and the better interface wettability between the matrix and the hybridized particles. Keywords: Hybrid composites, Bimodal size distribution, Microstructure, Tensile properties