Abstract : Graphite creep has high importance for applications using high pressures (100 MPa) and temperatures close to 2000 °C. In particular, the new flash spark plasma sintering process (FSPS) is highly sensitive to graphite creep when applied to ultra-high temperature materials such as silicon carbide. In this flash process taking only a few seconds, the graphite tooling reaches temperatures higher than 2000 °C resulting in its irreversible deformation. The graphite tooling creep prevents the flash spark plasma sintering process from progressing further. In this study, a finite element model is used to determine FSPS tooling temperatures. In this context, we explore the graphite creep onset for temperatures above 2000 °C and for high pressures. Knowing the graphite high temperature limit, we modify the FSPS process so that the sintering occurs outside the graphite creep range of temperatures/pressures. 95 % dense silicon carbide compacts are obtained in about 30 s using the optimized FSPS.
https://hal-normandie-univ.archives-ouvertes.fr/hal-02616747 Contributor : Charles ManièreConnect in order to contact the contributor Submitted on : Friday, November 20, 2020 - 8:34:32 PM Last modification on : Thursday, January 13, 2022 - 4:14:02 PM
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Charles Manière, Geuntak Lee, Joanna Mckittrick, Andrey Maximenko, Eugene A. Olevsky. Graphite creep negation during flash spark plasma sintering under temperatures close to 2000 °C. Carbon, Elsevier, 2020, 162, pp.106-113. ⟨10.1016/j.carbon.2020.02.027⟩. ⟨hal-02616747⟩