Influence of calcium on specific heat capacity and changes in thermodynamic functions of aluminum conductor alloy AlTi0.1

Abstract

Aluminum in terms of electrical conductivity among all known metals ranks fourth after silver, copper and gold. The electrical conductivity of annealed aluminum is approximately 62% IACS of the electrical conductivity of annealed standard copper, which at 20 °C. is taken as 100% IACS. However, due to its low specific gravity, aluminum has a conductivity per unit mass 2 times greater than copper. This property of aluminum gives us an idea of the economic viability of using it as a material for conductors. With equal conductivity (the same length), the aluminum conductor has a cross-sectional area 60% larger than copper, and its mass is only 48% of the mass of copper. In most cases, in electrical engineering, the use of aluminum as a conductor is difficult, and often simply impossible due to its low mechanical strength. An increase in the mechanical strength of aluminum is possible due to the introduction of alloying additives, i.e. creating alloys. In such a case, the mechanical strength increases, causing a noticeable decrease in electrical conductivity. The heat capacity of the aluminum conductor alloy AlTi0.1 (Al + 0.1 wt.% Ti) with calcium in the “cooling” mode was determined from the known heat capacity of the standard aluminum sample. Equations are obtained that describe the cooling rates of specimens made from an aluminum conductor alloy AlTi0.1 with calcium and a reference. Based on the calculated values of the cooling rates of the samples, the equations for the temperature dependence of the heat capacities of the alloys and the standard were formed. The temperature dependences of changes in enthalpy, entropy, and Gibbs energy for the aluminum alloy AlTi0.1 with calcium are calculated by integrating the specific heat capacity. The heat capacity, enthalpy, and entropy of the AlTi0.1 alloy decrease with increasing calcium concentration, and increase with increasing temperature, while the value of the Gibbs energy has an inverse relationship.