Influence of Structure and Dispersivity of Copper on its Melting Features

Abstract

The melting parameters (melting point, specific heat of fusion) of copper samples with different volume structure (fine-grained, submicrocrystalline) and dispersivity (fine powder) were explored using differential thermal analysis. It was found that change in the metal structure from bulk coarse-grained to submicrocrystalline, and to submicron powders led to depression of melting point by ~18 °C and of specific heat of fusion by ~45 % relative to the standard values. It was shown that the high-energy impact on the starting coarse-grained metal used to obtain the samples with modified structure and dispersivity (severe plastic deformation, electric explosion of thin wires) caused changes in the composition of the material. An explanation for the observed influence of structure and dispersion factors on the melting parameters has been proposed on the basis of X-ray diffraction data, electron microscopy, and model calculations.