Jan Vollhüter, M. Göken, Steffen Neumeier
A hierarchical precipitate structure enhances the strength of ferritic BCC superalloys. This concept is extended to Cr-based systems, aiming to realize superior mechanical strength in chromium alloys for challenging environments. The addition of Ti to the Cr-NiAl system leads to the formation of a nanostructured intermetallic compound consisting of B2 and L21 phases, which surround the dendritically solidified Crss. TEM and APT investigations reveal a network of B2 and L21 Heusler phases arranged in lamellar or rod-like morphologies. Compression creep tests show three orders of magnitude improvement in the Ti-containing α/α′/α″ Cr alloy over the α/α′ Cr alloy.