Processing of Magnesium-Based Metal Matrix Nanocomposites by Ultrasound-Assisted Particle Dispersion: A Review

Magnesium-based metal matrix nanocomposites (MMNCs) are an important topic in the development of lightweight structural materials, because their optimized properties are of great interest to the automotive and aerospace industries. Moreover, components with functional properties will also be manufactured from Mg-MMNCs in the future. With a large surface to volume ratio, nanoparticles in the magnesium matrix have an immense effect on mechanical properties, even at low concentrations. The mechanical properties of these materials can be tailored using ceramic nanoparticles, which have been available at a very low cost for a number of years. However, the particle concentration, chemical composition, particle size, and process parameters must be attuned to the respective alloy, in order to influence the resulting properties. When using very small particles, a major problem is to homogeneously distribute the particles in the melt. Due to their large surface area, strong van der Waals forces act to hold the particles together in clusters. At the same time, wettability of the particles with a magnesium melt is very poor. Ultrasonic stirring processes have proven their effectiveness in the de-agglomeration and dispersion of nanoparticles. This review presents ultrasound-assisted processes for the production of these materials and describes some properties of the resulting Mg-MMNCs