Faculdade de Engenharia Química de Lorena – FAENQUIL, Departamento de Engenharia de Materiais – DEMAR, Polo Urbo-Industrial Gleba AI-6, Mondesir, Caixa Postal 116, 12600-000, Lorena, São Paulo, Brazil
Abstract:
Ni–Nb alloys have been used as master-alloy in the production of Ni-based superalloys containing niobium. In the case of INCONEL 718, the most used superalloy, the niobium content is in the range 5.0–5.5 wt%. The aim of this work is to present results related to the production of Ni-65wt%Nb alloy by aluminothermic reduction process. Two different reactant mixtures were used: Nb2O5 + Ni + Al and Nb2O5 + NiO + Al. For each type of mixture the Al excess was varied from 0% to 15% over the stoichiometric amount. All the alloys were produced in a bulk form with Nb and Ni composition according to specifications. The best results came from the experiments involving mixtures of Nb2O5 + NiO + Al, where an overall metallic yield of 86% was obtained. The alloys produced from Nb2O5 + Ni + Al mixtures showed low metallic yields and high oxygen contents associated to the presence of a niobium oxide-phase in the microstructure.