Thermal Conductivity of Double Continuous Disordered Solid Solutions
- PDF / 155,463 Bytes
- 3 Pages / 612 x 792 pts (letter) Page_size
- 76 Downloads / 176 Views
mal Conductivity of Double Continuous Disordered Solid Solutions Yu. P. Zarichnyaka, *, A. E. Ramazanovab, and S. N. Emirovb aNational
Research University of Information Technologies, Mechanics, and Optics, St. Petersburg, 197101 Russia Institute for Geothermal Research, Dagestan Scientific Center, Russian Academy of Sciences, Makhachkala, 367030 Russia *e-mail: [email protected]
b
Received March 19, 2020; revised April 10, 2020; accepted May 27, 2020
Abstract—A way of calculating the thermal conductivity of alloys (double continuous disordered solid solutions) is proposed. The procedure serves to estimate the thermal conductivity of different alloys (continuous solid solutions) as early as the stage of developing new materials with predetermined properties, using the minimum amount of initial information. It also allows the time and cost of creating trial samples and measuring their properties to be reduced considerably. DOI: 10.3103/S1062873820090385
INTRODUCTION Alloys of the group of continuous disordered solid solutions (substitutional solutions) are formed by replacing atoms/compounds of one of the components at the nodes of the crystal lattice with atoms/compounds of other components with the same type of crystal lattice. The difference between the atomic volumes of the components must not exceed 10–15%. Double systems with complete miscibility of the components are characterized by concave conductivity: a concentration curve with one minimum, the depth of which with respect to component conductivities λA and λB depends on the ratio of component conductivities and a solid solution with equiatomic/equi-mole xA = xB = 50 at % concentration of components. In copper–nickel alloy, the minimum value of thermal conductivity λAB of an alloy with an equi-atomic concentration of components is lower than the conductivity of copper by a factor of 20 [1]. The latter can be explained qualitatively: Atoms of impurities in В change the properties of initial component А. Each atom of the impurities in component B can be considered a defect of the microstructure in component А. Due to the change in the mass of an atom replaced with an impurity atom, the elastic forces of interaction with neighboring particles, the electric charge, and the electron density, the carriers of thermal energy are scattered more strongly in the vicinity of the impurity. The intensified distribution of the carriers on the defects reduces the conductivity of the solid solution. The concentration of defects in a volume unit of component А grows in proportion to the concentration
of the impurities, reaching its maximum at equiatomic or equi-mole concentrations. A further increase in the content of component В can be considered a reduction in the concentration of the impurity (component А), which is equivalent to reducing the concentration of defects in a volume unit of component В, accompanied by an increase in the thermal conductivity of the solid solution in the direction from the minimum to component В. APPROXIMATE PROCEDURE FOR CALCULATING DOUBL
Data Loading...
