Thermal and radiation-enhanced diffusion in the bulk metallic glass Ni₂₃Zr₆₂Al₁₅

The temperature dependence of tracer diffusion in the three-component system NiZrAl was measured. For the composition Ni₂₃Zr₆₂Al₁₅, it was possible to measure diffusion coefficients below and above the glass transition temperature. Similar to the binary metallic glass NiZr, the diffusion coefficient was strongly dependent on the atomic size of the tracer, varying by two orders of magnitude. The results are suggestive of a collective diffusion mechanism in bulk metallic glasses. Radiation-enhanced diffusion was also measured in this alloy and compared with measurements of radiation-induced viscous flow on similar alloys.