Neutron diffraction investigation of vacuum sintering in a binary Fe/Mn powder mixture.

Abstract This study investigated the sublimation of Mn and microstructural evolution of binary Fe/Mn compacts sintered at various temperatures in a vacuum. A high sintering temperature or a lengthy holding time promotes powder densification. Due to sublimation of Mn, the weight loss of the compacts mainly occurs during the isothermal holding stage of the sintering process; it increases significantly from 1.5 wt.% for sintering at 1000 °C to 8.6 wt.% at 1200 °C. For the first time, the phase evolution in the binary elemental compacts was clarified using in situ neutron diffraction. The γ-austenite phase emerges during temperature ramping to 536 °C, while β-Mn and α-Fe disappear at 774 °C and 881 °C. The neutron diffraction also revealed that single phase γ-austenite forms in the Fe-Mn compacts if the temperature is ≥ 881 °C. Highlights • In situ and real-time neutron diffraction was used to identify phase transition. • Sublimation behavior of Mn in Fe/Mn powder mixtures was investigated. • The sintered microstructure is related to sublimation of Mn. [ABSTRACT FROM AUTHOR]