Nauka ta progres transportu (Apr 2019)
PREDICTION OF THE PROPERTIES OF SINGLE-CRYSTAL HEAT-RESISTANCE NICKEL ALLOYS
Abstract
Purpose. This work aims to obtain predictive regression models, with which, one can adequately calculate the mechanical properties of single-crystal heat-resistant nickel alloys, without conducting preliminary experiments. Methodology. Industrial alloys for single-crystal casting of domestic and foreign production were selected for the research. Values were processed by the method of least squares with obtaining correlation dependencies with obtaining mathematical equations of regression models. Findings. As a result of processing the experimental data, a ratio of alloying elements has been proposed, which can be used to evaluate mechanical properties, which considers the complex effect of the main alloy components. Since the dimensional mismatch of the lattice parameters is related to the degree of solid-solution concentration hardening of the phases, the efficiency of the dispersion hardening of the alloy, the creep rate and other properties of single crystals, the ratio of alloying elements allows these properties to be associated with multi-component systems. The regression models are given, with the help of which it is possible to calculate the size mismatch, strength, heat resistance, amount of phase and density of alloys with high accuracy. The regularities of the influence of the composition on the properties of single-crystal heat-resistant nickel alloys are established. It is shown that for multicomponent nickel systems it is possible to predict with a high degree of confidence a misfit, which has a significant impact on the strength characteristics of alloys of this class. For single-crystal heat-resistant nickel alloys, an increase in the value of misfit is accompanied by a decrease in the limit of their short-term strength, since considerable stresses form between the crystal lattices of the phases, which contribute to structural and phase instability processes leading to premature destruction of the material. A correlation was established between the specific density and the average atomic mass of the alloys, as well as the limit of their short-term strength. Originality. For the first time, we proposed the ratio Кγ', with the help of which it is possible to adequately predict the properties of single-crystal heat-resistant nickel alloys, as well as regression models for predicting the main characteristics of casting single-crystal alloys. Practical value. A promising and effective direction in solving the problem of predicting the main characteristics affecting the complex service properties of alloys both in the development of new single-crystal heat-resistant nickel alloys and in improving the compositions of well-known industrial grades of this class is shown.
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