EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Ceramic particulate reinforced aluminium metal matrix nanocomposites (MMNCs) have been extensively developed for automotive and aerospace applications, due to their high-specific-strength. The ductility and toughness of the aluminium matrix combined with the strength and stiffness of the reinforcements manifests superior properties over the matrix. Both the ductility and toughness of the alloy can be potentially improved by the addition of nanoparticles. However, particle agglomerations, high porosity content, and weak particle/matrix interface bond are prone to occur in the casting process, arising from the introduction of the reinforcement, mould filling, and solidification process, especially when the particle sizes are approaching the nanoscale. This can lead to reduction in the mechanical properties achieved. High Pressure Die Casting (HPDC) is a cost-effective manufacturing technique for the mass production of aluminium castings exhibiting complex near-net-shape geometries. By applying high pressure and high cooling rates a better distribution of the reinforcing particles compared to other casting methods can be attained. This occurs because the high pressure improves the filling capacity of the composite melt, in which the fluidity is generally decreased by the added particles. The fine grain structure obtained under the high cooling rate is also beneficial for the distribution of the reinforcing nanoparticles during solidification. In this study, an AlSi9Cu3.5-1wt%SiC HPDC MMNC was produced by employing nano-masterbatches, stir mixing, ultrasonic processing and HPDC technology. This study will investigate the distribution and effects of the SiC nanoparticles on the resultant microstructure and mechanical properties.