Design precaution limitation
Creates high tensile strength and hardness
Improves wear resistance
Allows for easy machinability in soft state prior to age hardening
Performed at low temperatures
Allows for little to no distortion of the part or component
Precipitation hardening, also called age or particle hardening, is a heat treatment process that produces uniformly dispersed particles within a metal’s grain structure. These particles hinder dislocation motion and thereby strengthen the metal, particularly those that are malleable.
The formation of these precipitates is accomplished by using a solution treatment at high temperatures prior to a rapid cooling process. The solution heat treatment results in a single-phase solution while the rapid cooling results in a stable material by preventing the creation and propagation of lattice defects. This greatly strengthens the metal matrix. Precipitation hardening is typically performed in a vacuum, inert atmosphere at temperatures ranging from between 900º and 1150° F. The process ranges in time from one to four hours, depending on the exact material and the characteristics specified. As with tempering, a balance must be struck when precipitation hardening between the resulting increase in strength and the loss of ductility and toughness. Additionally, it is possible to over-age the material by tempering for too long, resulting in large, spread-out and thus ineffective precipitates.
Process of precipitation hardening