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Concentration and temperature dependence of decomposition in supercooled liquid alloys
Author(s) -
Löffler J.F.,
Thiyagarajan P.,
Johnson W.L.
Publication year - 2000
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889899014867
Subject(s) - spinodal decomposition , supercooling , annealing (glass) , materials science , glass transition , amorphous solid , scattering , neutron scattering , analytical chemistry (journal) , condensed matter physics , relaxation (psychology) , alloy , small angle scattering , thermodynamics , crystallography , chemistry , optics , phase (matter) , metallurgy , physics , psychology , social psychology , organic chemistry , chromatography , composite material , polymer
Small‐angle neutron scattering experiments were performed on the bulk amorphous alloy Zr 41.2 Ti 13.8 Cu 12.5 Ni 10 Be 22.5 (Vit1®, subscripts indicate at.%) and on other alloys, where the (Zr,Ti) and (Cu,Be) contents were varied by following the line in composition space connecting Vit1 and Zr 46.8 Ti 8.2 Cu 7.5 Ni 10 Be 27.5 (Vit4®). The small‐angle neutron scattering data of the samples, annealed at temperatures between 603 K and 663 K, show interference peaks, giving evidence for spatially correlated arrangements of inhomogeneities. The Q values of the interference peaks, Q max , decrease with increasing annealing temperature T a and, at a given annealing temperature, with composition following the connecting line from Vit1 to Vit4. Down to the glass transition temperature T g , the data follow a relation 1/ L 2 ∝ ( T s − T a ) as predicted by the linearized Cahn theory, with L = 2π/ Q max the characteristic wavelength of the decomposition and T s the apparent spinodal temperature. Below T g , a different behavior is observed, which may be either due to a change in atomic diffusion or due to an insufficient relaxation of the samples.