Cul'zhenko O. Thermodynamic analysis of phase equilibria and the structure of aluminum alloys doped with magnesium, silicon and germanium

The thesis is dedicated to the investigation of phase equilibria in the Al-Mg-Si, Al-Mg-Ge, Al-Mg-Si-Ge systems. The goal is determination of the compositions of binary (Al) + intermetallide eutectic alloys with high melting point, narrow temperature interval of crystallization, and large volume fraction of intermetallide in the structure of the eutectic. The method of thermodynamic calculation is developed, which allows preliminary assessment of the state diagrams for three- and four-component systems using the data for the two-component boundary state diagrams. The important features of the phase equilibria in the investigated systems of alloys are established. The results of the thermodynamic forecast are confirmed by an experimental research with use of methods of the thermal analysis and metallography. The concentration intervals were proposed for the compositions of alloys, on the basis of which new constructional materials can be developed.