Crystallization behavior and consolidation of gas-atomized Al84Gd6Ni7Co3 glassy powder

Gas-atomized Al84Gd6Ni7Co3 glassy powder displays a double-step devitrification behavior characterized by the precipitation of fcc Al in the first stage of the crystallization process, followed by the formation of intermetallic phases in the following crystallization event. Investigation of the crystallization kinetics reveal that the initial part of the glass-to-fcc Al transformation occurs by diffusion controlled growth with an increasing nucleation rate whereas the later stage of the transformation is dominated by the growth of the formed nuclei rather than by the generation of new nuclei. Highly dense bulk samples were produced by hot extrusion through the combined devitrification and consolidation of the glassy precursor. The consolidated samples exhibit remarkable high strength of about 1130 MPa combined with 3% fracture strain.