Although the two tempers are different in definition, there is not much difference between the 6063 aluminum, but mainly reflected in the difference in mechanical properties. The 6063T5 aluminum extrusion profile is generally air-cooled and naturally cooled during quenching in production. The 6063T6 aluminum extrusion profile is cooled by water to cool the aluminum material instantaneously so that the aluminum profile can reach higher hardness requirements. T6 temper is apparent with more top mechanical properties in strength, elongation, and hardness, and its process price is also higher than the cost of T5 temper process.
Considering the usage of your final product, if the material requirement on strength and hardness are relatively high, the 6063T6 aluminum extrusion can be selected, and if no particular need on strength and hardness, the 6063T5 aluminum extrusion can be chosen.