Skeleton castings macrostructure can be shaped in many ways, by choosing an appropriate material of cores and manufacturing technologies. Important factor, which puts foundry techniques over the other technologies of periodic cellular materials, is ability to adjust mechanical properties by changing the microstructure of an alloy from which the casting is made. The influence on the microstructure of the skeleton casting can be implemented by choosing the thermal properties, mainly thermal conductivity factor, of mould and core materials. Macro- and microstructure of skeleton castings with octahedron elementary cells was presented in this paper. The analysis concerns the differences in morphology of eutectic silicone depending on the location of measurements cross sections areas. The use of thermo-insulating material with appropriate properties assures correct fill of mould cavity and homogeneous microstructure on whole volume of skeleton casting. The selection of technological parameters of the casting process if very important as well.
The aim of the current study was to examine the structure of an alloy treated at various temperatures up to 2,000–2,100 °C. Among research techniques for studying alloy structure there were the electron and optical microstructure, X-ray structure, and spectral analysis, and for studying the developed furnace geometric parameters the authors employed mathematical modeling method. The research was performed using aluminum smelting gas-fired furnaces and electric arc furnaces. The objects of the study were aluminum alloys of the brand AK7p and AK6, as well as hydrogen and aluminum oxide in the melt. For determining the hydrogen content in the aluminum alloy, the vacuum extraction method was selected. Authors have established that treatment of molten aluminum alloy in contact with carbon melt at high temperatures of 2,000–2,100 °C has resulted in facilitating reduction of hydrogen and aluminum oxide content in the melt by 40-43% and 50-58%, respectively, which is important because hydrogen and aluminum oxide adversely affect the structure and properties of the alloy. Such treatment contributes to the formation of the extremely fine-grained microstructure of aluminum alloy.