Fabrication and Mechanical Properties of Al2O3 Reinforced NiAl Composites

Al2O3 reinforced NiAl composites can show better mechanical propertie s than monolithic NiAl. For enhancing the properties of NiAl/Al 2O3 composites NiAl powders were oxidized and/or ball milled to form Al 2O3 into NiAl matrix. The as-received and oxidized/ball milled NiAl powders were studied to determine the effects of oxidation and ball milling . Al2O3 particles are dispersed in the grain boundaries and within the NiAl grains of hot-pressed NiAl/ Al 2O3 composites. As the milling time and the oxidation temperature of NiAl powder incre ased, αAl2O3 contents increase, and fracture mode of the composite transforms from intergranular to transgranular cleavage which accounts for the enhancement of mechanical properties of NiAl/Al 2O3 composites.