Influence of Copper Additives on Heat Capacity and Thermodynamic Functions of A7E Brand Aluminum

The economic feasibility of applying aluminum as a conductor is explained by the favorable ratio of its cost (which has remained almost constant for many years) to the cost of copper. When using conducting aluminum alloys to fabricate thin wire, winding wire, etc., some difficulties can appear in connection with their insufficient strength and small number of kinks before fracture. In recent years, aluminum alloys have been developed which possess strength characteristics, making it possible to apply them as conductors even in the soft state. One promising consumer of aluminum is the electrotechnical industry. From here, the development of new compositions of alloys based on this metal is very urgent. The temperature dependence of the heat capacity of A7E aluminum alloys with copper is determined experimentally and the variations in their thermodynamic functions are calculated. Investigations are carried out using computers and the Sigma Plot program. Polynomials of the temperature dependence of the heat capacity and variations in thermodynamic functions (enthalpy, entropy, and Gibbs energy) of these alloys and a reference alloy (Al of the A5N brand), which have the correlation coefficient Rcorr = 0.992–0.998, are established. It is shown that heat capacity of A7E brand aluminum decreases with an increase in the copper content and increases with an increase in temperature. The enthalpy and entropy of alloys of A7 brand aluminum with copper increase with an increase in the copper fraction and decrease with an increase in temperature. The inverse dependence is characteristic of the Gibbs energy.