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 an d Nb powders. The manufacturing route involved full density consolidat ion of the starting blend followed by reactive hot pressing (RHP). The maximum processing temperature did not exceed 800 degrees C. The phas e composition and microstructure of materials obtained were characteri zed by X-ray diffraction, SEM/EDX and TEM. The kinetics and sequence o f phase formation during synthesis were investigated. No interaction b etween Nb particles and NiAl matrix was observed during processing or during longer anneals at 800 degrees C. Mechanical properties of the m aterial synthesized were evaluated in compression tests at different t emperatures and by microhardness measurements. Nb reinforcement was fo und to significantly increase the room temperature ductility of NiAl. (C) 1998 Elsevier Science S.A. All rights reserved.