A Study on Chemical Short Range Ordering in Pd40Ni40P20 Bulk Metallic Glass by Anomalous X-ray Scattering

A local change in the amorphous structure of bulk Pd40Ni40P20 glass during the thermal relaxation related to the chemical short-range order (CSRO) was examined by anomalous X-ray scattering (AXS) with energies near Ni and Pd K-absorption edges. The reversible CSRO process was confirmed by electrical resistance and density measurements. The environmental structural analysis around Ni and Pd revealed that the coordination number of Ni-Ni and Pd-Pd like-atom pairs increased with the degree of order formed in the CSRO process, while that of Ni-Pd unlike-atom pair decreased. The present analysis clearly indicates that the reversible CSRO process in the Pd40Ni40P20 bulk glass is inferred to be a local structural change such like the micro-phase separation.