Nanoscopic fluctuation in quenched Zr–Cu–Ni–Al metallic glasses and their welds examined by ASAXS at Zr–K edge

Anomalous small-angle scattering (ASAXS) measurements at Zr–K absorption edge were carried out to examine precursory structural and/or chemical fluctuation of quenched quaternary ZrCuNiAl bulk metallic glasses and their welds. The measurements were carried out at BL-40B2 of SPring8, Japan. The incident photon energies were about 30 and 100 eV lower than the K-absorption edge. The intensity profiles for the ZrCuNiAl alloys exhibited two characteristic scattering components. One is a monotonically decreasing component at low q, and the other is a shoulder component observed at higher q, suggesting a cluster-like fluctuation with a size of about a nanometer in radius. From the difference of the scattering intensity between the two energies, it is concluded that the scattering contrast between the clusters and the matrix is very low, with less than about one electron/atom, and chemical fluctuations is involved.