Alloys based on Fe3Al or FeAl with strengthening Mo3Al precipitates

Single-phase and two-phase ternary Fe–Al–Mo alloys with Al contents of about 30 or 40 at.% and Mo contents up to 23 at% have been studied with respect to hardness at room temperature, yield stress and fracture strain at room temperature and higher temperatures up to 1000 °C and oxidation at temperatures of 400–1000 °C. The alloys with atomic D03 or B2 order are strengthened by precipitation of the metastable τ2 phase and/or the stable Mo3Al phase, both hard and brittle intermetallic phases, depending on composition and heat treatment. The yield stress as well as the brittle-to-ductile transition temperature increases with increasing Mo content to reach yield stresses up to 1600 MPa with, however, fracture strains below 1% at low temperatures. The observed short-term oxidation is similar to that of other binary and ternary Fe–Al alloys.