Structure of Melt and Liquid Alloys

摘要: In the study of nucleation and growth crystals from melt, it is mandatory to determine accurately structure liquid phase up atomic level. However, analysis local liquids challenging because are locally ordered but disordered above a few shells neighbors. As consequence, diffraction pattern contains limited amount information on that requires, in principle, many parameters be described, contrast with crystalline materials. Nonetheless, techniques have been developed, among which scattering neutrons X-rays X-ray absorption technique (EXAFS) most widely used. Their output spherically averaged scattered intensity I ( θ ) normalized factor S q gives, by Fourier transformation, pair correlation function g r ), i.e., distribution interatomic distances. The has complemented characterization techniques: measurements various physical parameters, (density, conductivity, thermal properties), neutron inelastic spectra. addition, computer simulation contributed considerably our understanding phases (e.g., Monte Carlo simulation, ab initio molecular dynamics, reverse analysis). We review different approaches for systems scales simplest metallic structures more complex semiconducting alloy structures, under sample environments. emphasize importance large-scale facilities: sources synchrotrons. Some specific examples developed.