Effect of Mn content on the microstructure and mechanical properties of Mo2FeB2 based cermets

Five series of Mo2FeB2 based cermets with Mn addition between 0 and 10 wt% in 2.5 wt% increments were prepared by reaction sintering process. The effect of Mn content on the microstructure and crystalline phases was investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD). Hardness (HRA) and transverse rupture strength (TRS) were also measured. Mn addition improved the wettability of the Fe binder phase on the Mo2FeB2 hard phase, which resulted in a decrease in porosity and Mo2FeB2 grain size and an increase in phase uniformity. No Fe–Mn intermetallic compounds or other intermetallic compounds were detected with increasing Mn content. The TRS increased with increasing Mn content until it reached the maximum value at 10.0 wt% Mn addition. The hardness slightly increased with increasing Mn content firstly and then turned to decrease with increasing Mn content. The highest hardness was obtained for cermets with 5.0 wt% Mn addition.