It occurs in some metals, notably certain stainless steel, aluminum, and copper alloys at amblent temperature after solution heat treatment, the process being one of a constituent precipitating from solid solution. Where used, the consequences include increased strength and hardness, decrease ductility.
Age hardening
The aging at moderately elevated temperature expedites the process and is called:
Artificial Aging
A substance with metallic properties, compound of two or more elements of which at least one is metal.
Alloy
In steel are usually considered to be the metailic elements added for the purpose of modifying the properties
Alloying elements
It is the characteristics of exhibiting different properties when tested in different directions (as tensile strength " with grain" or "across the grain").