Influence of fabrication technique and matrix alloying on the interfacial shear strength of sapphire-NiAl composites

The influence of fabrication technique and alloying on the fiber matrix interfacial shear strength, measured using a fiber push-out technique, has been examined in sapphire fiber-reinforced NiAl matrix composites. The composites were fabricated using the powder-cloth (P-C) process, a casting process, and the zone directional solidification (DS) process. The NiAl matrix was alloyed with Cr, W or Yb. The results showed that, in general, cast and DS composites had higher interfacial shear strengths compared to the P-C composites containing binders. Neither matrix alloying nor casting and DS impaired the interface strength. The study highlights the potential of the DS process in designing dual-phase ductile microstructures in sapphire-reinforced NiAl alloys for improved toughness and strength