The Use of Computational Methods for Creating New Alloying Complexes of High-Temperature Alloys for GTE Parts

Processy litʹâ, 2019, Tom 134, №2, p.79-87

Abstract

Received 20.02.2019

UDK 669.245:513.71

The issue of the creation of new heat-resistant corrosion-resistant alloys for blades of stationary and transport turbines and the technology of their obtaining concern the actual problems of the field of domestic machine building. The article presents the results of the conducted studies related to the optimization of the alloying complex on the basis of a series heat-resistant corrosionresistant alloy of the type ХН60КВТЮМ. The authors add refractory elements of tantalum and rhenium to the main ingredients of a multi-component Ni–Co–Cr alloy on an austenitic base with carbide and intermetal type hardening due to the formation of disperse particles of the so-called γ′-phase. According to experimental studies, they are elements that, due to their physic-chemical characteristics, have the properties of both effective austenitic solid solution (rhenium) and active carbide and γ′-phase (tantalum) forming agents. The application of calculation methods to obtain linear regression equations and computer programs to optimize the ratio of the quantitative composition of elements along with the classic metal-physical selection of samples by conducting experimental melts, has made it possible to predict the level of performance characteristics and evaluate the phase-structural stability of the material in the process of long-term operation of turbine blades. In order to minimize the number of experiments, the method of the factor experiment was used and the linear complete models were obtained. Thus, the linear regression analysis showed the qualitative influence of the elements that are considered and confirmed the data of the literary review. Along with using the method of calculations by linear regression analysis, optimization of the system of doping according to the method of forecasting structural stability using computer programs using the method PHACOMP and computer program SPACE. In applying this program, data on the kinetics of the allocation of brittle phases, depending on the time and temperature of the operation of cast blades, and the peculiarities of structural transformations in the process of their long-term exploitation, were taken into account. The technique, which was tested earlier on the industrial brands of the ЧС70-ВI, ЧС88У-ВІ, ЧС-104, allowed to significantly reduce as a period of development of a new experimental alloy on the basis of mark SM-88Y, additionally doped with tantalum and rhenium, also significantly limit the experimental research.