Strengthening of Mg-Al-Zn-Mn alloy using SiC/Al nanocomposite extrusion

Abstract

The use of lightweight alloys such as magnesium (Mg) is critical for achieving improved fuel efficiency and reduced emissions for automobiles, as well as increased range for electric vehicles. To promote their use in industry, in replacing iron-based alloys, their mechanical properties must be improved. This can be achieved through the addition of fine ceramic particles, producing metal matrix composites. One of the most promising alloys of Mg is Mg-Al-Zn-Mn alloy. The current work examined the influence of SiC nanoparticles on the microstructure and mechanical properties of Mg-Al-Zn-Mn alloy composites. The additives were prepared via the extrusion of aluminum powder combined with 60 nm SiC particles. The resultant grain refinement was indeed significant, with a 54 % reduction for the 0.02 wt% SiC addition level. In addition, a more uniform dispersion of the β-Mg17Al12 phase and fine spherical clusters of Mg2Si were observed using scanning electron microscopy. The favorable morphology of the Mg2Si intermetallics and the fine grain size resulted in an improvement in tensile strength of approximately 32 %. The enhancements in mechanical properties were attributed to the Hall-Petch mechanism. Thus, the SiC-containing composite materials may be effectively used for light-alloy strengthening, leading to increased use of Mg alloys in industry.