Effect of core-shelled nanoparticles of carbon-coated nickel on magnesium

Magnesium alloys have great potential for widespread applications in automotive and aerospace industries. However, tremendous work is still needed to improve their mechanical properties, microstructures and workability. This paper investigates the effect of core-shelled nanoparticles (carbon-coated nickel) on pure magnesium. With about 4.9 wt.% (1 vol.%) of C-coated Ni nanoparticles dispersed by ultrasonic cavitation into pure Mg, the grain size of cast magnesium was refined markedly from more than 450 μm for pure Mg to 25 μm for Mg nanocomposites. The mechanical properties of Mg nanocomposites were also enhanced significantly by the addition of C-coated Ni nanoparticles. The microstructures were examined by Polarized Light Microscopy, SEM, and TEM. Theoretical study suggests that the yield strength enhancement of the nanocomposites is due to both Hall–Petch effect and Orowan strengthening.