L21-ordered Fe–Al–Ti alloys

Fe–Al–Ti alloys with the ordered L21-structure (Heusler phase) belong to the few Fe–Al-based alloys which show comparably high-strength at high temperatures, e.g. at 800 °C. However, like many other high-temperature materials based on intermetallics they show limited ductility even at high temperatures. In order to further explore the possibilities in increasing their strength and ductility, alloys with four different microstructures, i.e. single-phase L21, L21 with incoherent precipitates of TiB2 or Laves phase, and coherent L21 + A2, were produced. Also, the influence of alloying with Cr and B has been investigated. The Young's modulus of Fe–25Al–20Ti–4Cr (at.%) in dependence of temperature up to 900 °C has been determined and results of the compressive flow stress, creep strength and brittle-to-ductile transition temperatures (BDTT) are summarised and compared to those of binary Fe3Al (D03), Fe–Al–Ti-based alloys, and some commercial alloys.