Structural and phase transformations in alloy hypereutectic AL-18,5 % SI, processed liquid state periodic pulse electric shock

Raising of problem. Potential of traditional methods of management by quality of metal productions in the hard state practically outspent heat treatment. Perspective direction of improvement of the cast structure and operating descriptions of founding from silumins is treatment of fusion an electric current. For the increase of durability and plasticity of hypereutectic aluminium-silicon alloys, there are large crystals of primary silicon in the structure of that, they are modified by a phosphorous copper that is toxic and unfavorably influences on the state of environment. For development of purposeful methods of improvement structural properties of silumins affecting liquid phase an electric current is need all-round mutually complementary researches. It will allow not only to promote management efficiency quality of the cast wares by the method of out-of-furnace treatment of fusions an electric current but also will give an opportunity to extend the spheres of his use, in particular. Purpose. Expansion of ideas about the mechanism of retrofitting of hypereutectic silumins by periodic (cyclic) pulse electric current treatment of fusions, establishment of intercommunication of changes of microstructure and phase composition of alloy with the temperature and thermodynamics parameters of his melting and crystallization. Methodology. Complex researches by metallography, X-ray diffraction and thermal analysis (DTA) methods. Results. At the modes and methods of serve of electric signal worked out in-process the structure of fusion, near order of atoms, changes in Si-containing clusters, their size and by volume stake diminish. It assists reduction of specific heat of crystallization of primary crystals of silicon (Si1) more, than on 50 % and eutectic on to 2 - 4 %, increases of temperature liquidus on 20 - 25 K and decline of temperature solidus on 6 - 14 K comparatively with descriptions of initial alloy. Depending on the modes of treatment an electric current in the liquid state, during crystallization new modifications of silicon appear with the metallic type of inter-atomic interaction, a size and amount of Si1 diminish, even to their complete absence in a microstructure at researches by the method of optical microscopy. The thinly-differentiated of a-Al+P-Si eutectic is formed with the globular-like crystals of eutectic silicon in morphology with homogeneous distribution. Scientific novelty. Microstructure and phase changes, thermodynamics parameters of process of crystallization of phases, are first set in hypereutectic silumins treatment in the liquid state a periodic (cyclic) pulse electric current on the specially worked out modes. Practical meaningfulness. New knowledge about the process of retrofitting hypereutectic silumins by pulse electric current treatment is assist the purposeful search of ways of creation of new materials with fundamentally different properties.