Study on preparation and mechanical properties of Fe3Al–20 wt.%Al2O3 composites

Fe3Al–20 wt.%Al2O3 ultrafine grained composites were prepared by mechanical alloying (MA) with subsequent plasma activated sintering (PAS). Microstructures of the Fe3Al–20 wt.%Al2O3 composites and Fe3Al alloys were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrum (EDS) and transmission electron microscope (TEM). Then the relative density, room temperature hardness and compression property at 25–800 °C of the sintered samples were tested and analyzed. The results showed that Fe3Al–20 wt.%Al2O3 composites sintered at 1100 °C had fine grain size, high relative density, high hardness and excellent microstructure. The sharp drop in strength of Fe3Al alloys above 600 °C was improved via introducing 20 wt.%Al2O3 although the plastic toughness and strength at 25–400 °C of the composites was lower than Fe3Al.

► Fe3Al–20 wt.%Al2O3 were prepared by mechanical alloying inducing in situ Al2O3 grains. ► The phase of Fe3Al–20 wt.%Al2O3 were disordered Fe(Al) solid solution and α-Al2O3. ► Fe3Al–20 wt.%Al2O3 at 1100 °C sintering temperature had good comprehensive performance. ► 20 wt.%Al2O3 can improve high temperature strength (⩾600 °C) of Fe3Al alloys.