Heat Treated Alloys achieve optimal mechanical properties through a process of heat treatment (most commonly solution heat treatment and artificial aging). The solution heat treatment process involves heating an alloy to a relatively high temperature (approximately 990 degrees Fahrenheit) to dissolve the alloying elements or compounds into solution. Subsequently, it is usually quenched in water, producing a supersaturated solution at room temperature.
Solution heat treatment is usually followed by aging. Aging is the precipitation of a portion of an element or compound from a supersaturated solution to obtain desired properties.
The aging process is divided into two types: aging at room temperature, which is "natural aging", and aging at high temperature, which is "artificial aging". Artificial aging temperatures are typically around 320 degrees Fahrenheit. Many heat-treatable aluminum alloys are used in welding fabrication in their solution, heat treatment, and artificial aging conditions.
Non-heat treatable alloys obtain optimal mechanical properties through strain hardening. Strain hardening is a method of increasing strength through the application of cold working.
