Rudenko M. Monotektic type copper-based alloys with improved indicators of mechanical, physical and special features.

The object of study - the process of dissolving components dispersed phase in copper-based alloys Cu - (Fe - Cr - C) at temperatures up to 850 ° C. The aim is to develop a process to obtain castings of improved (with improved operational performance stability, hardness and conductivity at elevated temperatures) monotektyс Cu - (Fe - Cr - C) alloy. Methods: microrengenospectral methods and chemical analysis - for determination of reinforcing additives and alloys in general; optical metallography methods - to study the structure of alloys; method of thermodynamic analysis - to determine the thermodynamic parameters of the phases and the likely equilibrium state of the system as a whole. The hardness of the samples was collected and measured for deter-Brinelya method. The electrical resistance of the samples was determined by the voltmeter-ammeter for chotyryzondovoyu wiring. Number of phases that formed in the structure of the investigated alloy by reducing the ro-zchynnosti elements during cooling solid solution based on copper, eye-solicitation for the change in indicators of hardness and resistivity after artificial aging (at 500 C) prezaharto emyh (with temperature 850 C) samples. Changes in the degree of solubility of components dispersed inclusions at the base when heated assessed by temperature dependences of resistivity alloys. The scientific novelty of the results. Based on the results-max analysis phase thermodynamic parameters revealed that the system Cu - Fe system can be considered monotektychnoho type. Melts of the system, depending on the iron content may be in the form of two liquid phases, which differ in structure: phase of copper and iron-based phase. However, due to lack of the interaction parameters as in the liquid phase of copper and liquid phase based on iron concentration length field of two-phase state melts extremely small. It is confirmed that the introduction of additional carbon concentration leads to extension length field of two-phase melt state system Cu - Fe. The use of Cu - (Fe - Cr - C) to create alloys, media-tsnenyh inclusions formed in the melt, is warranted. Established that the existence of melt system Cu - (Fe - Cr - C) in the two-phase state is possible with carbon content in (Fe - Cr - C) addition of not less than 0.5 wt. %. As a result of the dissolution of the components of additives in the liquid phase of copper in the structure of alloys of Cu - (Fe - Cr - C) in addition to inclusions that form lis liquid-based (Fe - Cr - C) additives may be present and blotches which formed on cooling due to reduced solution-ness elements in the basis (phase based alloys). It was established that the greatest stability for dissolution in liquid copper, with components (Fe - Cr - C) pre-bavok, whose structure in the range of crystallization consists of gamma solid solution of iron-based liquid phase. The increase in the number of carbon in these supplements leads to reduction of their components in the liquid phase of copper. At the same time, in the solid state stability of the largest components of dispersed phases on the basis of dissolution is achieved when injected into the melt (Fe - Cr - C) additives, phase composition range in which the crystal-mentation represented delta solid solution (iron-based) and liquid phase. Increasing the chromium content of 27.6 to 32.2 wt. % And reducing the carbon content of 1.5 to 1 wt. % Of additives leads to increased stability of inclusions. Found that in Cu - (Fe - Cr - C) alloys, (Fe - Cr - C) supplements contain 1.4 - 1.6 wt. % Carbon and 15 - 17 wt. % Chromium (base - iron), optimally combined with the characteristics of the technological properties of hardness and conductivity at temperatures above 650 0C. The practical significance of the results is to develop the alloy system Cu - (Fe - Cr - C), with enhanced performance ex-pluatatsiynoyi stability and conductive properties at elevated temperatures, and production technologies of casting it. The said alloy has passed industrial tests at JSC "Ventilation systems". Tests show that the operational stability of the welding electrodes developed alloy exceeds the stability of such sys-ktrodiv bronze BrH 1 half.