During creep, magnesium alloys undergo microstructural changes due to temperature and
stress. These alterations are associated with the evolution of the present phases at a microstructural
level, creating different strain rates during primary and tertiary creep, and with the stability of
the inter-metallic phase Mg17Al12 formed at these temperatures. In this paper, the results of creep
testing of high-pressure die-cast AZ91 magnesium alloys are reported. During creep, continuous and
discontinuous precipitates grow, which influences creep resistance. The creep mechanism that acts at
these intermediate temperatures up to 150 ◦C is termed dislocation climbing. Finally, the influence of
the type of precipitates on the creep behavior of alloys is determined by promoting the formation of
continuous precipitates by a short heat treatment prior to creep testing.
