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Results of a study on microstructural evolution of eutectic Sn-57 wt.% Bi processed with cooling rates of 10 −2 , 1 K s −1 and approximately 10 5  K s −1 are presented. In order to distinguish different mechanisms of microstructure formation, a comparison with microstructures of different hypoeutectic alloys with compositions down to below the maximum solubility of Bi in Sn–Bi is undertaken. It is found that at the cooling rates of 10 −2 and 1 K s −1 , coupled eutectic growth occurs, leading to lamellar structures with different length scales. At the rapid quenching rates of approximately 10 5  K s −1 , structure formation in the eutectic alloy is qualitatively different. Partitionless solidification resulting in a supersaturated solid solution with the initial composition is observed in both eutectic and hypoeutectic alloys. It is shown that the observed microstructure of the rapidly solidified alloys forms by the decomposition of the supersaturated solid solution. This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.

Ultrarapid quenching processes have been extensively studied during the past few years. particularly for glasses. In the case of polycrystalline materials, the problem is slightly different. In this case, the microstructures obtained by this process are very different from those obtained by normal cooling and they induce new physical properties.

, Phone: þ375 29 577 28 00, Fax: þ375 17 209 54 45Grain structure and the temperature dependences of resistivity, magnetoresistance, Hall and Seebeck coefficients measured in the range from 4 to 300 K were investigated for polycrystalline bismuth films obtained by the melt spinning (MS) and electrochemical deposition (ECD) methods. Charge-carrier concentration and mobilities were calculated assuming the carrier scattering on acoustic deformation potential as the dominant scattering mechanism, parabolicity of holes dispersion law, implying the Lax model for L-band electrons and neglecting the influence of L-band holes on conductivity. The experimental results and calculations have demonstrated that the electrical properties of the Bi films studied are strongly affected by the grain-boundary density.