A Critical Review on Heat Treatment of Aluminium Alloys

In the modern world, smart materials play a vital role. There are many methods to improve the mechanical and material properties, one among them is by reinforcing different materials into aluminium. Without reinforcing the material, properties can be altered by heat treatment. Age hardening is done for the aluminum and its alloys. Only 2XXX, 6XXX, and 7XXX are heat treatable. The Al2024 alloy is solution heat-treated (T3&T6) with different temperatures and aging exhibits optimum strength and hardness due to the presence of coherent Guinier Preston (GP) zones and ultrafine grains of Nano-sized S-phase (Al2CuMg) precipitates. Hardness can be improved by coating technique later persisting with artificial aging, restricting the cooling rate and heat transfer. The Al6061 is solution heat-treated (T4&T6) and artificially aged; here Al6061 alloy is treated with T4 results in higher formability but lower yield strength whereas T6 treated results in lower formability but higher yield strength. The tensile strength and yield strength of the Al 6XXX series vary accordingly 6005 > 6106 > 6063 > 6061. The 7XXX series alloys are treated with precipitation hardening which improves stress corrosion cracking, hardness, reduces ductility, and ultimate tensile strength. To overcome SCC retrogression and re-aging, which has similar microstructure precipitates of T6 and over-aged T7 condition, Double aging > RR > T6 condition methodology. The current work has the collective details of the effects of heat treatment on aluminum alloy and its composite material.