Friction surfacing of aluminium alloys

Dissertação para a obtenção do grau de Mestre em Engenharia Mecânica

Friction surfacing is a solid state joining process that has attracted much interest in the past decades. This technology allows joining dissimilar metallic materials while avoiding the brittle intermetallic formations, involving temperatures bellow melting point and producing like forged metal structures. Much research using different steels has been made but the same does not happen with aluminium alloys, specially using different aluminium alloys. Friction surface coatings using consumable rods of AA6082-T6 were produced on AA2024-T3 plates using a wide range of parameters. Coatings were examined to assure the best set of parameters according to the physical properties, such as: bonding width and thickness. Coatings were characterized metallurgical and mechanically. Besides metallurgical techniques, hardness, tensile, bending and wear tests were carried out. From this study, it was shown that high rotation speeds reduce the coating thickness and improve bonding to the substrate, while the applied load is the key parameter to obtain a good bonding width. Travel speed controls the deposition rate and the coating thickness. For the tested parameters a fine grain structure was obtained. The coatings have similar properties to the as-received rods but with higher ultimate tensile strength (UTS), elongation and wear resistance. Finally, an assessment of power and material consumption was performed revealing that Friction Surfacing is quite competitive when compared to other surface coating technologies.