FUNCTIONALLY GRADED TANTALUM/NIOBIUM CARBIDE

Hard materials resist wear, but are prone to fracture. Tough materials resist fracture, but are susceptible to wear. Ideally, a material should possess a combination of high hardness and high fracture toughness, but designing such a material has proven difficult. A novel tantalum or niobium carbide (TaC or NbC) results in a composite with superior strength and fracture toughness. The material consists of two-phases, a hard carbide on the outside and a tough carbide in the interior. The carbide substrate can be produced using conventional powder processing methods to fabricate complex shapes and surface-treatment. The proposed material outperforms tungsten carbide in applications that require hardness, fracture toughness, and corrosion resistance.