Fe-Al　compounds　possess　a　combination　of　high　strength　and　corrosion　resistance　at　high　temperatures.　However,　increasing　Al　content　to　make　them　lighter　results　in　embrittlement.　Here,　we　investigate　the　high-temperature　behavior　of　a　novel,　lightweight,　ultra-fine-layered　FeAl/FeAl2　material.　We　report　a　transition　from　unstable　to　stable　plasticity　at　450　°C.　Below　450　°C,　deformation　is　dominated　by　localized　shear　deformation　within　the　soft　FeAl　layers,　while　above　450　°C,　it　proceeds　by　co-deformation　between　FeAl　and　the　brittle　FeAl2　layers.　We　show　that　co-deformation　is　associated　with　the　temperature　at　which　the　interface　converts　from　sliding　to　sourcing　dislocations　for　FeAl2.　©　2020