Surface Reinforced Aluminium Composites Fabricated with Friction Stir Processing

Alumina particle reinforced metal matrix composites were manufactured on the surface of aluminum alloy (AA) 5082 substrates using friction stir processing. Specifically, alumina ceramic particles were filled into a... [ view full abstract ]

Alumina particle reinforced metal matrix composites were manufactured on the surface of aluminum alloy (AA) 5082 substrates using friction stir processing. Specifically, alumina ceramic particles were filled into a discontinuous pattern of holes machined on the surface of 12.5 mm thick AA5082 plates and then incorporated with friction stir processing using linear passes. For all the trials, the surface modification of the processed materials was targeted to be up to 5 mm in depth with an average reinforcement volume fraction of 10 % alumina particles. The process development studies indicated that the homogeneity of the particle distribution along the direction of tool translation and defect formation were related to the processing parameters such as tool rotational rate, translation speed and number of linear passes. For process conditions enabling homogeneously distributed ceramic particles within the composite surface layer, an increase of 15-30% in hardness was achieved as compared to the parent metal. Also, the hardness doubled in some local areas that had high concentrations of ceramic particles.