AbstractA novel high shear dispersion technique (HSDT) was used for the ﬁrst time to effectively distribute AlN/Al nanoparticles (NPs) in Elektron21 (El21) Mg alloys. Different high shearing speeds were adopted to investigate the optimum shearing speed for optimum deagglomeration of NPs and enhancing the creep resistance of AlN/Al NPs reinforced El21 alloy. The results showed that the creep resistance of El21 + 0.5% AlN/Al nanocomposite increased with the increasing speed of HSDT. The individual/synergistic roles of AlN and Al were also systematically identiﬁed by comparing the microstructural evolutions and creep properties of El21, El21 + 0.25% Al, El21 + 0.75% AlN, and El21 + 1% AlN/Al. The creep results showed that the mixture additions of AlN and Al NPs gave a synergistic improvement on the creep resistance of El21 alloy compared to the single addition of Al or AlN NPs.