6xxx series is Aluminum alloy which components Al-Si-Mg-Cu. After Solution heat treatment and Quenching, α phase in the matrix alloy change to α+θ . But θ phase do not mix with α phase (Not homogeneous). Artificial Aging is a homogeneous process that equilibium mixture between θ phase and matrix α phase. When matrix is homogeneous, the hardness increases in this alloy. Applications of artificial aging include Fuselage of a civil aircraft, Transport, Truck frames etc. Solution Heat treatment heat work pieces to 540˚C keep temperature for 1 hr. Then take work pieces to quench in water. Natural Aging leave work piece in freeze for one week. Artificial aging heat to 170˚C at 10 min, 1 hour, 2 hours, and 4 hours. After that, the measurement of hardness and plot the Brinell hardness graph for considering about hardness of Al alloys 6xxx series. From the graph show you about relation between hardness and aging time.
● T4 - solution heat-treated and naturally aged
● T6 - solution heat treated then artificially aged in the T6 has higher strength but lower ductility than the same alloy in the T4 temper
● T7 - solution heat-treated and then overaged / stabilized