Embrittlement and local structures for the Cu-, Ni- and Zr-based bulk metallic glasses

To study the microscopic reasons for the embrittlement of the bulk metallic glasses, the local structures around main constituent atoms, i.e. Zr, Ni and Cu in the Zr60Al15Ni25, Ni60Nb20Ti15Zr5 and Cu60Zr30Ti10 glasses (numbers indicate at.%) were investigated by X-ray absorption fine structure measurements. The fluctuations in the interatomic distance (σ2) of the main constituent atoms in the three metallic glasses are deduced from the results. The σ2 value for Zr in the Zr60Al15Ni25 was highest in terms of temperature variation as well as in the absolute value among the three metallic glasses even though Zr has the largest atomic size among the constituent atoms. A peak in the Fourier transform of the Zr K-edge for Zr60Al15Ni25 at a short distance may be associated with oxygen around Zr atoms.