Effect of alkaline earth metals on the heat capacity and change of thermodynamic function of AK1M2 alloy on the basis of specific aluminum

Abstract

It is known that high purity aluminum with a minimum content of impurities is widely used in electronic technology for the manufacture of conductive paths in integrated circuits. Hence the development of new compositions of alloys based on such a metal is a very urgent task. One of the promising alloys based on such a metal is alloy AK1M2 (Al + 1 % Si + 2 % Cu). This alloy was accepted by us as a model alloy and subjected to modification by alkaline earth metals.Heat capacity is the most important characteristic of substances and by its variation with temperature one can determine the type of phase transformation, the Debye temperature, the energy of formation of vacancies, the coefficient of electronic heat capacity, and other properties. In the present work, the heat capacity of the AK1M2 alloy with alkaline earth metals was determined in the “cooling” mode from the known heat capacity of a reference sample from copper. For which, by processing the curves of the cooling rate of samples from the alloy AK1M2 with alkaline earth metals and the standard, polynomials were obtained which describe their cooling rates. Further, by experimentally found values of the cooling rates of the standard and samples from alloys, knowing their masses, the polynomials of the temperature dependence of the heat capacity of the alloys and the standard were established, which are described by a four-term equation. Using the integrals of the specific heat, the models of temperature dependence of the change in enthalpy, entropy and Gibbs energy were established.The dependences obtained show that with an increase in temperature, the heat capacity, enthalpy, and entropy of alloys increase, and the values of Gibbs energy decrease. At the same time, additives of alkaline earth metals do not significantly reduce the heat capacity, enthalpy and entropy of the original alloy AK1M2 and increase the value of Gibbs energy. During the transition from alloys with calcium with barium, the heat capacity of the alloys decreases, which correlates with the heat capacity of pure alkaline earth metals within the subgroup.