Properties of Mg-based Metal Matrix Nanocomposites Processed by High Shear Dispersion Technique (HSDT) - A Review

Metal Matrix Nanocomposites (MMNCs) often show excellent properties as compared to their non-reinforced alloys due to either the achieved grain refinement or Orowan strengthening. Especially in light metals such as aluminium and magnesium as the matrix has the potential to be significantly improved in relation to mechanical properties. Functionalisation can also be achieved in some cases. However, the challenge lies in the homogeneous distribution of the ceramic nanoparticles in the melt if MMNCs have been processed via melt metallurgical processes. The large surface area of the nanoparticles generates large van der Waals forces, which need to be overcome. Furthermore, the wettability of the particles with molten metal is difficult. Additional forces can be applied by ultrasound, electromagnetic stirring, or even high-shearing. In this paper, properties of MMNCs with a light metal matrix, which have been produced with the High-Shearing Dispersion Technique are discussed. First, the process with its different characteristics and the underlying theory is presented, and then property improvements are discussed by comparing MMNCs to their matrix materials.