Effects of rhenium on glass formation and mechanical properties of metastable ZrCuAl alloys

The effect of small additives of Re on a metallic glass forming alloy (Cu46Zr46Al8)100-xRex (x = 1, 2) was investigated for samples of different sizes. Re possess a positive enthalpy of mixing within the Cu-Re terminal system. Splat quenched foils of ∼40 μm thickness display amorphous structure. Their crystallization temperature increases from Tx = 500 to 510 C with increasing Re fraction at nearly constant glass formation temperature Tg = 440 C. By contrast, injection cast rods consist of B2 - CuZr type metastable phase dendrites, a cubic CuZrAl type phase and randomly distributed small particles of a Re-rich phase. The presence of metastable phases leads to a unique combination of mechanical properties of as-cast rods which display high strength at sizeable plastic deformation up to εp ∼4% and an extended range of work hardening prior to failure.