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a b s t r a c tBased on the available experimental information, the Au-Ge binary system has been thermodynamically assessed using the CALPHAD method. The solution phases including liquid, fcc A1, hcp A3, diamond A4, bct A5 and D024, were modeled as substitutional solutions, of which the excess Gibbs energies were expressed by the Redlich-Kister polynomial. The solubility of Ge in Au 5 Sn, AuSn, AuSn 2 and AuSn 4 was not taken into account due to the lack of experimental data. Combined with previous assessments of the Au-Sn and Ge-Sn binary systems, the thermodynamic description of the Au-Ge-Sn ternary system has been performed to reproduce the reported phase equilibria. The liquidus projection and several vertical sections of this ternary system have been calculated, which are in reasonable agreement with the reported experimental data.

It is shown that the neutron small‐angle scattering of pure polycrystalline metals is strongly connected with surface imperfections in the samples (surface irregularities and oxide layers) rather then with the grain boundaries. It is also shown that the asymptotic form of the scattering cross section of the surface imperfections is q−4 like the Porod law.

Short-range order parameters were obtained for a single crystal of 62Ni3Fe quenched from above T c. These are the first absolute measurements of diffuse elastic neutron scattering complete enough to separate the effects of local order and atomic displacements (up to quadratic terms) and indicate that neutrons are ideally suited for such studies. The results are compared to those obtained with X-rays. The short-range order intensity of Ni3Fe is similar in shape to that for Cu3Au but in this alloy it is due to the plate-like nature of ordered domains, not the antiphase domain boundaries which are present in such regions in Cu3Au.