Microstructure and mechanical properties of Fe–Mn based alloys after sub-rapid solidification

Highlights: • Mechanical properties were improved with a low fraction of epsilon martensite. • Sub-rapid solidification can evidently refine the structure size of Fe-Mn based alloy. • Sub-rapid solidification can directly produce Fe-Mn sample with high properties. - Abstract: The purpose of this paper was to investigate the microstructure and the mechanical properties of Fe–(11, 13 and 17) wt.% Mn alloys prepared by using sub-rapid solidification technique. X-ray diffraction showed that α′-martensite with body-centered cubic structure was the major phase formed in the Fe–11 wt.% Mn sample, while ε-martensite with hexagonal close-packed structure apparently appeared when Mn content reached to 13 wt.% and its volume percentage increased with the Mn content. The ε-martensite has needle shape and band structure in the Fe–Mn alloy. Mechanical property tests showed that the yield strength decreased while elongation increased as Mn content increased from 11 wt.% to 17 wt.%. The tensile strength of Fe–13 wt.% Mn sample was found to be the highest among all samples. Addition of 0.14 wt.% carbon could increase tensile strength and elongation of Fe–11 wt.% Mn alloy while decrease its yield strength