Beryllium self-diffusion in the deeply supercooled state of a Zr46.7Ti8.3Cu
7.5Ni10Be27.5 alloy has been studied by a radiotracer technique by employin
g the isotope Be-7 in combination with ion-beam sectioning. The temperature
dependence of the diffusivity D is Arrhenius like with D(T)=10(2.6) m(2) s
(-1) exp(-2.6 eV/k(B)T). The tracer diffusivities consistently extend the s
ize dependence of the diffusion observed in the supercooled liquid state of
this alloy to the smallest constituent, but are at variance with previousl
y published results of chemical Be diffusion. (C) 2001 American Institute o
f Physics.