| Abstrakt: |
The structural state and phase composition of Fe-B-C alloys containing 2.0-9.0% wt. В, 0.1-0.2% wt. С, Fe--balance cooled at 10-10³ К/s are studied in this work. The methods of microscopy, quantitative metallography, and xray analysis are applied. Microhardness, compressive strength, coefficients of relative abrasive, and gas-abrasive wear resistance are measured. Hypereutectic Fe-B-C alloys exhibit elevated microhardness, which ensures higher resistance to abrasive wear. Hypoeutectic alloys possess enhanced compressive strength, which ascertains their higher gas-abrasive wear resistance at room temperature. The highest resistance to gas-abrasive wear at 473 K show hypereutectic alloys due to higher oxidation resistance of their structural constituents. As cooling rate increases from 10 to 103 K/s, structure of Fe-B-C alloys changes since lines of phase diagram are shifted towards the iron corner. A content of primary austenite increases in the hypoeutectic alloy, and a content of primary Fe2(B,C) phase decreases in the hypereutectic alloys. Meanwhile, microhardness of the alloys increases, but compressive strength increases firstly in the range of cooling rates from 10 to 300 K/s and, then, decreases at higher rates. The hypereutectic Fe-B-C alloys containing 10-20% vol. of Fe-Fe2(B,С) eutectics in the structure cooled at 8.10²-10³ K/s exhibit the best performance properties. These alloys can be applied as filler materials for composite coatings working under abrasive and gas-abrasive wear conditions, even at temperatures up to 473 K. [ABSTRACT FROM AUTHOR] |
