Influence of calcium addition on the thermophysical properties and thermodynamic functions of aluminum alloy AlCu4,5Mg1
I.N. Ganiev1, R.S. Shonazarov2, A. Elmurod3, U.N. Faizulloev4, A.G. Safarov5
1Institute of Chemistry named after V.I. Nikitin NAS of Tajikistan, Dushanbe, Tajikistan
2Bokhtar State University named after Nosir Khusrav, Bokhtar, Tajikistan
3Dangara State University, Dangara, Tajikistan
4National Research Technological University (NUST) “MISiS” in Dushanbe, Dushanbe, Tajikistan
5Physical-Technical Institute named after S.U. Umarov NAS of Tajikistan, Dushanbe, Tajikistan
Keywords: aluminum alloy AlCu4,5Mg1, calcium, “cooling” mode, heat capacity, enthalpy, entropy, Gibbs energy
Abstract
The cooling rates of the studied alloy samples were determined in the "cooling" mode, by constructing thermograms of cooling alloys and their subsequent differentiation. Considering the heat capacity of the standard (Al brand A5N) and the cooling rates of the samples and the standard, the temperature dependence of the heat capacity of the aluminum alloy AlCu4,5Mg1 doped with calcium was calculated. Computer processing of the results served to obtain a polynomial of the temperature dependence of the heat capacity of alloys in the form of a four-term equation with the correlation coefficient R ≤ 0.999. It has been found that the heat capacity, enthalpy, and entropy of the alloys increase with increasing temperature, while the value of the Gibbs energy decreases. Additions of calcium in the range of 0.05 -1.0 wt. % reduce the heat capacity, heat transfer coefficient, enthalpy and entropy of the AlCu4,5Mg1 aluminum alloy, and the Gibbs energy has an inverse relationship.
|
