High Velocity Oxy-Fuel Spray Formed Bulk Aluminium Matrix Composites-Development and Characterization

Abstract

In the present study, bulk Aluminium matrix composites (AMCs) reinforced by alumina (Al2O3) particulates (Al/Al2O3) are developed by High Velocity Oxy-fuel (HVOF) thermal spray technique. The HVOF spray technique has been used by many researchers to deposit composite coatings, but there is less available literature discussing the development of bulk metal matrix composites by this technique. The composite powders, as a feed stock of HVOF spraying, was prepared by ball milling of pure Al powders with 15 wt.%, 20 wt.% and 25 wt.% Al2O3 particles. The feedstock was deposited on to a die steel metallic substrate. The deposited composite material was then separated from the die steel. Microstructures of the composite powders and the newly developed composite materials were analyzed by Optical Microscopy (OM), Scanning Electron Microscopy (SEM)/Energy Dispersive Spectroscopy (SEM/EDS) and EDS elemental mapping techniques. X-ray Diffraction (XRD) analysis was done to reveal the phases present in the as-sprayed specimens. Porosity and hardness value of the composites was also measured. The study showed the possibility of preparing bulk aluminum metal matrix composites of larger size by HVOF spray technique.