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.