Composition and structure of the diamond/low carbon steel transition zone obtained by contact heating in vacuum at Fe–C eutectic temperature
| Autor: | S. N. Makharova, P. P. Sharin, S. P. Yakovleva, M. P. Akimova, V. I. Popov |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Carbon steel Cementite Materials Science (miscellaneous) Metals and Alloys Diamond 02 engineering and technology engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Surfaces Coatings and Films Vacuum furnace chemistry.chemical_compound chemistry Ferrite (iron) Ceramics and Composites engineering Lamellar structure Cast iron Composite material 0210 nano-technology Eutectic system |
| Zdroj: | Izvestiya vuzov Poroshkovaya metallurgiya i funktsional’nye pokrytiya. :47-59 |
| ISSN: | 2412-8767 1997-308X |
| DOI: | 10.17073/1997-308x-2021-1-47-59 |
| Popis: | The study covers the structure, elemental and phase composition of products formed in the contact interaction between diamond and low-carbon steel in vacuum at the Fe–C eutectic melting temperature. Cylindrical tablets made of low carbon steel with a maximum carbon content of 0.1 wt.% and natural diamond crystals in the form of a pyramid (or truncated pyramid) were used as contact pairs. The flat bases of diamond crystals were mounted on the horizontal surface of steel tablets with the load applied to the top of diamond crystals. Contact samples were sintered in a vacuum furnace at a maximum heating temperature of ~1165 °C. After holding at this temperature for 5 minutes, the furnace was turned off and the temperature in its chamber decreased in free cooling mode. Sintered diamond/steel tablet samples were studied by optical and scanning electron microscopy, X-ray diffraction analysis and Raman spectroscopy. It was found that the Fe–C eutectic melt forms in the diamond/steel tablet contact zone, a thin layer of which, when solidified, welds a diamond crystal to the steel tablet under the temperature-time heating mode specified in the experiment. Their bonding strength is such that welded samples without separation can withstand intense cyclic loads during grinding and polishing when making longitudinal sections of samples necessary for metallographic studies. It was shown that the Fe–C eutectic alloy is a gray cast iron with a ferrite-perlite metal base and lamellar graphite inclusions. The microhardness of the solidified Fe–C eutectic was ~1714 MPa. The initial steel tablet with a ferrite-perlite structure was subjected to cementation during sintering in contact with diamond. The most intensive cementation occurred in the ~110 μm thick unmelted upper layer of the steel tablet, which adjoined the Fe–C eutectic during sintering. The microhardness of this layer was ~4945 MPa. As it deepens into the steel tablet there is a gradual transition of the perlite-cementite structure to a perlite one and further to the initial ferrite-perlite microstructure inwards the steel tablet. At the same time, the microhardness changes from ~ 4945 to 1570 MPa. |
| Databáze: | OpenAIRE |
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