Magnesium Matrix Composites: State-of the-Art and what’s the Future

Abstract

A huge number of different process types are in use to produce magnesium-based composites. Depending on the reinforcement type, all the processes can be subdivided into solid state or powder metallurgical (PM) and liquid phase or ingot metallurgical (IM) processes. In this paper we will focus on ingot metallurgy processes. These liquid state processes result quite often in a very good interface of reinforcement with the magnesium matrix. The liquid processes can be further subdivided into infiltration techniques, casting processes and spray deposition. Those are the most inexpensive processing technologies for discontinuous, reinforced magnesium-based composites. When produced using melting processes, nanoparticle-reinforced magnesium composites are expected to improve in strength, due to the grain refinement described in the Hall-Petch relation. When an isotropic distribution of nanoparticles is achieved, the composites are additionally expected to be Orowan-strengthened. That is why nanosized reinforcements are expected to represent the future for improving the properties of magnesium-based metal matrix composites.