The strength and hardness of some metal alloys may be enhanced by the formation of extremely small
uniformly dispersed particles of a second phase within the original phase matrix; this must be accomplished
by appropriate heat treatment.

The process is called Precipitation Hardening or Age Hardening which involves three distinct steps:
    Solution Treatment to minimize segregation in the alloy,
    Quenching to create a supersaturated solid solution and
    Aging to facilitate the formation of coherent precipitates which strengthen the alloy by interfering with dislocation movement.

Both the Natural Aging and Artificial Aging processes will be investigated by measuring the hardness of 2024 aluminum specimens at various time intervals into the aging process following the quench. Phenomena related to precipitation hardening, such as Guinier-Preston zones, overaging, coherent participates, etc., will be discussed.

Return back to experimental course: Materials of Engineering Laboratory
http://imechanica.org/node/1061