Abstract
The positron lifetime τ1 of Pd77.5Cu6Si16.5, Fe75P16B6Al3, and Ni75P16B6Al3 glass increases from ∼170 ps to a plateau value ∼175 ps immediately following an anneal at 350 K for 30 min. With further annealing above 500 K, τ1 decreases and approaches ∼165 ps. Possible atomic clustering in metallic glasses during structural relaxation will be described.