Synthesis and viscoelasticity of Zr-based bulk glassy alloy containing ZrC particles

Cylindrical composite Zr₅₅Al₁₀Ni₅Cu₃₀ bulk glassy alloys containing up to 17.5 vol.% ZrC particles were prepared with using an in-situ reaction forming ZrC between graphite particles with diameters of ∼10 μm and Zr metal in molten alloy during arc-melting followed by copper mold casting. Because the in-situ reaction suppresses an agglomeration and segregation among dispersoids in the glassy matrix, mechanical properties of the composite materials at room temperature, especially toughness and plastic elongation, were significantly improved from the Zr₅₅Al₁₀Ni₅Cu₃₀ single glassy phase. In order to demonstrate the influence of the dispersed ZrC particles on workability of the supercooled liquid of the alloy, viscous flow behaviors under constant strain-rates were investigated. Although the Newtonian viscosity becomes larger, the composite material has the same viscoelastic properties, i.e., "shear thinning", and excellent workability as the single glassy phase in spite of the dispersed particles.