Machinability study of aircraft series aluminium alloys 7075-T6 and 7050-T7451

Abstract

The aluminium alloy 7050-T7451 is generally considered as the principal choice in aeronautical applications demanding adequate strength, stress corrosion cracking resistance, and toughness. Surprisingly, despite extensive research works on machining and machinability of aluminium alloys, including aluminium alloy 7075-T6, limited information was found on machining and machinability evaluation of 7050-T7451, which belongs to a similar family as 7075-T6. To remedy the lack of knowledge determined, dry ball-end milling operations were performed with coated end milling tools on both materials. Experimental characterization and cutting force measurements were performed to measure/evaluate the cutting forces, burr formation morphology, insert performance (wear/breakage), and surface quality attributes. According to experimental studies, 7050-T7451 was found more machinable than 7075-T6. Less burr formation and better surface quality were observed on 7075-T6. Machining attributes are influenced by different experimental factors. However, other machinability attributes, including residual stress, vibration modes, as well as particle emission, must be studied under various lubrication modes and machining operations in subsequent studies. This also recalls further studies on simultaneous multiple response optimization.