Solid state synthesis of NiAl–Nb composites from fine elemental powders

Dense NiAl matrix composites reinforced with ductile Nb particles were synthesized in solid state from the blend of fine elemental Ni, Al and Nb powders. The manufacturing route involved full density consolidation of the starting blend followed by reactive hot pressing (RHP). The maximum processing temperature did not exceed 800°C. The phase composition and microstructure of materials obtained were characterized by X-ray diffraction, SEM/EDX and TEM. The kinetics and sequence of phase formation during synthesis were investigated. No interaction between Nb particles and NiAl matrix was observed during processing or during longer anneals at 800°C. Mechanical properties of the material synthesized were evaluated in compression tests at different temperatures and by microhardness measurements. Nb reinforcement was found to significantly increase the room temperature ductility of NiAl.