Effects of Re microalloying on glass formation and mechanical properties of Zr–Cu–Al alloys

Abstract

The effect of microalloying with rhenium on a metallic glass-forming alloy (Cu46Zr46Al8)100− x Re x (x = 1, 2) was investigated. Re possesses a positive enthalpy of mixing within the Cu–Re terminal system. Splat quenched foils of ≈40 µm in thickness display an amorphous structure. Their crystallisation temperature increases from T x = 504 to 513°C with addition of Re at nearly constant glass formation temperature T g = 445°C for the amorphous samples. In contrast, injection cast rods consist of B2-CuZr type phase dendrites, minor fractions of a cubic phase CuZrAl, and randomly distributed small particles of a Re-rich phase. This represents a novel concept in microalloying where Re-rich precipitates trigger the B2 phase formation. It leads to a unique combination of mechanical properties for as-cast rods, which display high strength at sizeable plastic deformation up to ε p ≈ 4% and an extended range of work-hardening prior to failure.