Atom probe studies of metallic glasses

Abstract Atom probe tomography was used to characterize the distribution of atoms in bulk amorphous Pd 40 Ni 40 P 20 , Pd 40 Ni 40− x Fe x P 20 (0 x 50 Cu 50 ) 100− x P x ( x =16.5, 17.5, 19) alloys. The analyses were performed on samples cut from 7-mm diameter rods, which were prepared by quenching the melt at cooling rates of approximately 200 K/s. All the alloys were examined in the as-quenched condition. In the Pd 40 Ni 40− x Fe x P 20 glasses, the increase in Fe concentration causes a systematic increase in the clustering of palladium and ordering of phosphorus. The 20% Fe alloy exhibited a two-phase microstructure. The (Pd 50 Cu 50 ) 100− x P x glasses exhibited fine-scale phase separation into copper-enriched/phosphorus-depleted and copper-depleted/phosphorus-enriched regions. These observations follow from statistical analysis of the concentration frequency distributions, the composition enrichments of shells around each atom, and composition maps.