Microhardness of сompacted thermally expanded graphite

Autor: T. G. Avramenko, V. O. Andruschenko, K. O. Ivanenko, M. M. Melnichenko, S. L. Revo
Rok vydání: 2019
Předmět:
Zdroj: Bulletin of Taras Shevchenko National University of Kyiv. Series: Physics and Mathematics. :170-174
ISSN: 2218-2055
1812-5409
DOI: 10.17721/1812-5409.2019/1.40
Popis: Using the method of continuous microindentation with different loading on the indenter, the microhardness of compacted thermo-expanded graphite (TEG) samples of different dispersion was studied. The analysis of the obtained results showed that, with an increase in the average cross-sectional area of TEG particles from 40 to 120 microns, the microhardness of the samples under investigation also increases. An analysis of the influence of the dispersion and morphology of the TEG particles on the distribution of microhardness on the surface of the compacted samples of TEG was also carried out. The microhardness indicatrix for the samples of the original TEG shows that when the radial displacement from the center of the sample, the microhardness of the material decreases. So in the central part of the discoid sample the values of microhardness lie in the range from 0,04 to 0,025 GPa. In the next concentric region, the microhardness decreases by 30% and gains a value of (0.028 ... 0.014) GPA. When the dispersion of TEG particles changes, the distribution of microhardness also changes. The microhardness indicatrix for a compacted Tg sample with an average particle size of 180 μm shows that the microhardness value at the center of the sample ranges from 0.065 to 0.15 GPa.As you approach the edge of the sample, the microhardness of the material decreases from 0.15 to 0.054 GPa. The study of TEG with an average particle size of 50 μm showed that the indentation in the center and in the middle region of the sample gives an isotropic distribution of microhardness values. The microhardness values coincide in the central and middle regions of the sample and correspond to ≈ 0.1 GPa. The proposed method of research and analysis of microhardness on the surface of compacted specimens of TEG gives an opportunity not only to characterize the micromechanical properties of the investigated material but also to optimize the technological regimes for obtaining samples.
Databáze: OpenAIRE
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