Microstructure and Mechanical Properties of Al2O3/NiAl In Situ Composites by Hot-Press-Aided Reaction Synthesis

Abstract

Al2O3/NiAl composites were successfully fabricated by hot-press-assisted exothermic dispersion method with elemental powder mixtures of Ni, Al, NiO. The content of Al2O3 on the microstructures and mechanical properties of Al2O3/NiAl composites has been characterized. The results show that the Vickers hardness, flexural strength and fracture toughness of the composites increase with increasing Al2O3 content. When the Al2O3 content is 15 wt %, the flexural strength and the fracture toughness peaked at 765 MPa and 9.67 MPa•m 1/2, respectively. The improvement of mechanical properties is associated with a more homogeneous and finer microstructure developed by addition of Al2O3.