Effect of fabrication methods on microstructure and mechanical properties of Fe3Al-based alloys

Disordered Fe(Al) solid solution powders with nano-grain size were fabricated by mechanical alloying, and subsequently the milled powders were consolidated by plasma activated sintering (PAS) and hot pressing (HP), respectively. The effect of the two fabrication methods on microstructure and mechanical properties of Fe3Al was investigated. Disordered Fe3Al with submicron-grain size was obtained by PAS, while ordered Fe3Al with micron-grain size was obtained by HP. Compared with ordered Fe3Al with micron-grain size by HP, disordered Fe3Al with submicron-grain size by PAS had higher hardness and toughness. Fe3AlC0.5 was precipitated in all specimens with methanol addition during mechanic alloying. The precipitation of Fe3AlC0.5 improved the hardness of Fe3Al, but was harmful to the toughness of Fe3Al.