Mechanical properties of Al-based metal matrix composites reinforced with Zr-based glassy particles produced by powder metallurgy

Abstract

Al-based metal matrix composites consisting of pure Al reinforced with different amounts of mechanically alloyed Zr₅₇Ti₈Nb_2.5Cu_13.9Ni_11.1 Al_7.5 glassy powder were produced by powder metallurgy, and their mechanical properties were investigated by room temperature compression tests. The samples were consolidated into highly dense bulk specimens at temperatures within the supercooled liquid region in order to take advantage of the viscous flow behavior of the glassy powder. Compression tests show that the addition of the glass reinforcement increases the strength of pure Al from 155 to 250 MPa, while retaining appreciable plastic deformation with a fracture strain ranging between 70% and 40%. The yield strength and the elastoplastic deformation of such composites containing a high volume fraction of glassy particles were accurately modeled using a shear lag model and a self-consistent effective medium approach. Finally, the fracture characteristics of the reinforcing particles were rationalized using a proposed fracture criterion.