Crystallization in homogeneous and phase-separated Pd _41.25Ni_41.25P_17.5 bulk metallic glasses

Earlier, it was shown that molten Pd_41.25Ni _41.25P_17.5 alloys can be cast into BMGs (bulk metallic glasses) of different microstructures, which are: (i) homogeneous BMGs (A-type), (ii) homogeneous BMGs embedded with crystalline precipitates (B-type), and (iii) phase-separated BMGs (C-type). Their crystallization behaviors were studied in this paper. At low annealing temperatures, the crystallization is characterized by spherical precipitates, each of which consists of a nanocrystalline core and a eutectic crust. The cores of the three types of BMGs are not of the same composition. At high annealing temperatures, there are cubic precipitates in addition to the spherical precipitates. For reference purposes, the crystallization of amorphous Pd₄₀Ni₄₀P₂₀, a widely studied BMG, was examined. It was found that spherical precipitates, with a core composition different from those of Pd_41.25Ni _41.25P_17.5 BMGs, appear, but cubic precipitates are absent.