Interface-facilitated stable plasticity in ultra-fine layered FeAl/FeAl₂ micro-pillar at high temperature

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.