ACCURATE PREDICTIONS FOR PRACTICE STEMMING FROM THE QUANTUM THEORY OF GRANULAR STRUCTURE

This article presents the results of research on practical predictions of a number of important operational and technological properties of materials and their explanation based on the quantum theory of granular structure. The impossibility of explaining the granular structure and related properties of materials based on classical concepts has led many researchers to the idea of the need for a quantum description of these properties and phenomena. The quantum theory of granular structure that we are developing is based on the universal Bogolyubov Hamiltonian for condensed quantum systems or on an ensemble-averaged wave function and an expression for free energy or the Gibbs thermodynamic potential, similar to the Ginsburg-Landau potential in superconductivity theory. The exact solutions of the equations of the theory in the nonstationary case describe the growth of crystals from melts and the formula of the crystal growth rate and the shape of the crystal that follows from the solutions, which previously remained mysteries. The exact solutions of the equations of the theory in the stationary case describe the crystal structure, and from periodic solutions a formula is obtained describing the grain sizes depending on temperature, pressure, material parameter and the quantum number of the stationary quantum state. The analysis of the expression for Gibbs energy shows that the thermodynamic Onsager-Prigogine forces act in the thermodynamic system, transferring the quantum system from one stationary state to another, accompanied by a decrease in Gibbs energy and an increase in grain sizes, to recrystallization processes. Both the formation of a granular structure and grain sizes, as well as its recrystallization, remained a mystery to all materials scientists. The recrystallization formulas made it possible to explain and describe such mysterious phenomena as hot sintering, the process of twinning of boundary grains at a temperature that allows such twinning. Formulas have been obtained for the temperature allowing sintering depending on the fractional particle sizes of the raw material. As the grains grow, thermodynamic forces drop to zero and recrystallization stops, rapid destruction of the material occurs - loss of mechanical stability. This is the mechanism of aging, and the theory provides an accurate formula for longevity, devoid of contradictions and considering the granular structure. Considering the ultimate strength of a material as a load at a given temperature, at which the durability is a time of ten seconds, we obtain a theoretical formula for the dependence of the ultimate strength of a material on temperature. Assuming that the temperature of the beginning of plastic deformation of a previously brittle material is the temperature at which the recrystallization rate begins to grow rapidly, we obtain the theory of plastic deformation and the temperature of refractoriness. All these numerous and different predictions based on the quantum theory of granular structure coincide with the experiment with great accuracy.