A neutron diffraction study of Al-rich glasses

Abstract

Incoherent, multiple, inelastic and transmission corrections in Al 8.5Y x Ni 15− x glasses are negligible, making them very well-suited for quantitative structural studies by neutron scattering. Differential scanning calorimetry has shown that there is an abrupt change in the mode of crystallization when the Y/Ni ratio equals to one. For x⩽7.5 crystallization proceeds by a pure growth process, while for x>7.5, nucleation as well as growth are involved in the crystallization process. This suggests a distinct change in the configurational short-range order of these glasses. Neutron diffraction results indicate that Y-rich glasses show exceptionally long short-range order (12–15 Å for x = 10) and homogeneous glass nearest-neighbor distances. Y-poor glasses show a decreased short-range order (about 8 Å for x=5) with nearest-neighbor distances indicative of compositional inhomogeneity.