Magnesium alloys are used predominantly for high-pressure die-cast applications in which the use of a deliberate heat treatment is uncommon. This article provides information on the heat treatment designations for magnesium alloys. It describes the effects of grain size on magnesium alloys and the relationship between hardness and mechanical properties of the alloys. The article discusses the effects of elements such as aluminum, zinc, manganese, rare earths, and yttrium, on precipitation hardening. It describes the types of heat treatment for magnesium alloys, including annealing, stress relieving, solution treating and aging, and reheat treating. The article also discusses the preventive...