A comparative review of machinability in AA2XXX and AA7XXX heat-treatable aluminum alloys: Focus on AA7050-T7451 and AA2050-T84

Heat-treated AA7050-T7451 with high fatigue strength and corrosion cracking resistance, which is frequently used in the aerospace industry, and third generation AA2050-T84 with low density, high fracture toughness, and high hardness strength is distorted due to high chip removal volumes during machining. During machining, depending on the cutting parameters, the cutting forces and high heat transfer during machining cause residual stresses to accumulate on the bulk material. Residual stresses are one of the main causes of distortion theory and one of the most important factors that increase the scrap rate in the machining industry. The observation of a higher risk of distortion in high-volume removal processes such as turning, drilling, milling, etc. has led to the optimization of cutting parameters with a view to reduce the residual stress. In AA7050-T7451 and AA2050-T84, high cutting forces and heat transfer movements vary depending on the material microstructure as well as the spindle speed, feed, cutting type, and cutting tool parameters. The aim of this review is to examine the microstructures and the causes of distortion during the milling of Al alloys, especially AA7050-T7451 and AA2050-T84 for using the aerostructures. The distortions during machining are influenced by the microstructure of the materials, the type of cutter due to chemical reactions, and the cutting parameters due to the heat and cutting forces generated. It can be observed and improved by machining variables such as chip morphology, cutting force analysis, and surface roughness. The effect of cutting parameters such as spindle speed, feed rate, and cutting speed on the distortion of AA7050-T7451 and AA2050-T84 are investigated. As a result, cutting parameters have a crucial effect on the residual stresses in AA7050-T7451 and AA2050-T84 materials.