Effect of Mo on microstructure and mechanical properties of bulk nanocrystalline Fe3Al materials prepared by aluminothermic reaction

Bulk nanocrystalline Fe3Al based materials with 5, 10 and 15 wt-% Mo were prepared by aluminothermic reaction. The microstructure and mechanical properties of the materials were investigated. It was shown that the materials consisted of a nanocrystalline matrix phase that was composed of Fe, Al and Mo and a little Al2O3 contamination phase. The nanocrystalline phase had a disordered bcc crystal structure. Average grain sizes of the nanocrystalline phase of the materials with 5, 10 and 15 wt-% Mo were 19, 31 and 24 nm respectively and that of the material with 5 wt-% Mo was the smallest. The materials with 10 and 15 wt-% Mo exhibited brittle behaviour in compression, whereas the material with 5 wt-% Mo had a large plastic deformation. The material with 5 wt-% Mo had the highest bending strength and the lowest compressive yield strength.