  Intermetallic phases can significantly improve the creep resistance of
magnesium alloys, extending their use to higher temperatures. However, little
is known about the deformation behaviour of these phases at application
temperatures, which are commonly below their macroscopic
brittle-to-ductile-transition temperature. In this study, we therefore
investigate the activation of different slip systems of the CaMg$_2$ phase and
the occurrence of serrated yielding in the temperature range from 50$^\circ$C
to 250$^\circ$C. A decreasing amount of serrated flow with increasing
temperature suggests that solute atoms govern the flow behaviour when the
CaMg$_{2}$ phase is off-stoichiometric.
