Obtaining mechanically fused modifying ligatures with a high content of alloying component for the production of chrome bronzes

The paper presents the results of a study of the regularities of the formation of granulometric composition, structure and properties of modifying ligatures with a high content of alloying component for the production of chrome bronzes. The kinetics of changes in the physico‑mechanical properties of granular compositions depending on the temperature in the grinding chamber and the ratio of the volume of working bodies to the volume of the charge has been studied. The results of the topography of granules and their structure are presented, showing that the granules obtained according to the optimal mode of mechanical fusion are dense bodies with microinclusions of chromium, the maximum size of which does not exceed 15–20 microns.

Based on the results of thermodynamic modeling, thermodynamically justified refractory compounds synthesized in the process of obtaining a ligature have been established, which should effectively perform the role of modifiers of the first kind, ensuring the production of bronzes with a sub‑/microcrystalline type of base structure.

The processes of compacting mechanically fused compositions were optimized and the influence of the main technological factors – the heating temperature of cold‑pressed briquettes and the extraction coefficient during hot pressing on the physical and mechanical properties of compact materials was investigated. The results of studying the structure and properties of the most promising Cu – 20 %Cr composition are presented, which make it possible to identify its microcrystalline type, which persists after prolonged high‑temperature exposure during the processing of the granular composition into a semi‑finished product, and to conclude about the dispersed nature of its hardening, which additionally confi ms the data of thermodynamic modeling on the possibility of mechanical synthesis of nanocrystals of refractory compounds to perform the role of modifiers.

According to the results of the research, a comparative analysis of the properties of the developed ligature and beryllium bronze was performed, establishing the possibility of its use as an independent material for electrical purposes.

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