Effect of high pressure during the fabrication on the thermal and mechanical properties of amorphous Ni₆₀Nb₄₀ particle-reinforced Al-based metal matrix composites

Ni₆₀Nb₄₀ metallic glass particles, prepared by mechanical alloying, were used to fabricate Al–30 wt% Ni₆₀Nb₄₀ metal matrix composites (MMCs) at 823 K by sintering, hot pressing, and hot extrusion. The Ni₆₀Nb₄₀ reinforcements remained amorphous in all the MMCs fabricated by the different methods. Compression tests revealed that the Young’s modulus and yield strength of the MMCs produced by hot-pressing and hot-extrusion are higher than those for the sintered specimens. Differential scanning calorimeter (DSC) annealing of the as-produced MMCs at 913 K revealed there are severe interfacial reactions between the Al matrix and the Ni₆₀Nb₄₀ reinforcements. The DSC isotherms indicate that the Al matrix reacts faster with Ni₆₀Nb₄₀ in the hot-pressed and hot-extruded MMCs than it does in the sintered material.