Aluminum Age-Hardening Kinetics
Time- and temperature-dependent progression of precipitate formation in age-hardenable aluminum alloys to achieve maximum strength values. This process is based on the formation of coherent Guinier-Preston zones.
Age hardening in aluminum alloys happens via finely dispersed precipitates in the structure that really make the material strong. When welding, this is tricky: the heat from welding can destroy the carefully set hardening in the heat-affected zone, making the material softer there. If you need to restore strength after welding, that means: solution annealing, quenching, and then controlled aging. The exact temperatures and times depend on the alloy, so you have to check the data sheet, not guess. If you age too hot or too long, the material gets soft again—overaging is the keyword.