Mechanical synthesis and rapid consolidation of nanocrystalline TiCo-Al2O3 composites by high frequency induction heated sintering

Abstract

Despite of many attractive properties of TiCo, TiCo in industry has been limited due to low fracture toughness and a low hardness. The mechanical properties can be improved significantly by reinforcing TiCo with hard ceramic particles such as Al2O3 and by fabrication of nanostructured composite. Nanomaterials have received a good deal of attention recently as they possess high strength, high hardness, excellent ductility and toughness. In recent days, nanocrystalline powders have been developed by the thermochemical and thermomechanical process named as the spray conversion process (SCP), co-precipitation and high energy milling. Nano-powders of TiCo and Al2O3 were synthesized from CoTiO3 and 2Al powders by high energy ball milling. Nanocrystalline Al2O3 reinforced composite was consolidated by high frequency induction heated sintering within one minute from mechanochemically synthesized powders of Al2O3 and TiCo. The relative density of the composite was 98%. The average hardness and fracture toughness values obtained were 1180 kg/mm(2) and 8.5MPa.m(1/2), respectively.