Microstructure and mechanical properties of Fe-Al-Ti-B alloys with additions of Mo and W

Four quinary Fe-Al-Mo-Ti-B and Fe-Al-W-Ti-B alloys based on Fe3Al produced by vacuum induction melting were investigated regarding their microstructure and mechanical properties. The microstructures consist of a Fe3Al matrix with complex borides along grain boundaries. Compared to other Fe3Al-based alloys the present alloys show favourably low ductile-to-brittle transition temperatures (BDTT) and a markedly high creep strength at 650 °C. The latter is most pronounced for an alloy whose strength, besides strengthening by solid solution hardening through Mo and by the boride precipitates, is further enhanced by stabilising the D03-ordered structure up to higher temperatures.