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This study aims to develop a magnesium-based hybrid composite via a powder metallurgy(PM)technique by simultaneously reinforcing the matrix(Mg-3Zn-0.7Zr-lCu)alloy with micro-alumina(3.0 wt％)and nano-alu-mina(0.5 wt％and 1.0 wt％)particulates.The extensive processing involved two different sintering temperatures(400 and 450℃)followed by hot extrusion and a heat treatment process.The study aimed to add to our under-standing of the effects of sintering temperature and alumina content on the physical characteristics of Mg-based com-posites.It was revealed that increasing sintering tempera-ture improves the density of composites by increasing their diffusion rates.In addition,significant improvements in the hardness,tensile properties and compressive properties of the composites were observed at higher sintering temper-atures.It was also discovered that composites with higher alumina concentrations experienced agglomeration and were more porous than other composites.A micro-struc-tural examination showed that composites with higher concentrations of nano-alumina had a finer grain structure than other composites and underwent a marginal reduction in grain size.However,the tensile and compressive prop-erties of composites decreased when the nano-alumina content was increased to 1.0 wt％.The magnesium hybrid composite containing 3.0 wt％micro-alumina and 0.5 wt％nano-alumina sintered at 450℃displayed the greatest tensile strength properties in all composites studied.A transformation from brittle to mixed-mode failure,with sufficient evidence of increased plastic deformation,was also noted in the hybrid composites.The present study suggests that adding up to 0.5 wt％nano-alumina and employing a higher sintering temperature enhances the overall characteristics of magnesium/alumina micro-composites.