Mechanical properties of in-situ toughened Al2O3/Fe3Al

Mechanical properties of in-situ toughened Al2O3/Fe3Al nano-/micro-composites were measured. Effects of Fe3Al content, sintering temperature and holding time on properties and microstructure of the composites were investigated. The addition of Fe3Al nano-particles decreased the aspect ratio and grain size of Al2O3, and changed the fracture mode of composites. The maximum bending strength and fracture toughness were 832 MPa and 7.96 MPa m1/2, which were obtained in Al2O3/5 wt.% Fe3Al sintered at 1530 °C and Al2O3/10 wt.% Fe3Al sintered at 1600 °C, respectively. Compared to monolithic alumina, the strength increased by 132% and the toughness increased by 73%. The improvement in the mechanical properties of the composites was attributed to the change in fracture mode from intergranular fracture to transgranular fracture, the “in-situ reinforced effect” arising from the platelet grains of Al2O3 matrix, refined microstructure by dispersoids, as well as crack deflection and bridging of intergranular and intragranular Fe3Al.