Graphite creep negation during flash spark plasma sintering under temperatures close to 2000 °C

Charles Manière (1) , Geuntak Lee (1) , Joanna Mckittrick (2) , Andrey Maximenko (1) , Eugene A. Olevsky (1)

1 SDSU - San Diego State University
2 MAE - UC San Diego - Department of Mechanical and Aerospace Engineering [Univ California San Diego]

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.

Keywords: Graphite Creep; High Temperatures; Flash Spark Plasma Sintering; Simulation; Silicon Carbide; Sintering

Domains: Chemical Sciences; Material chemistry; Engineering Sciences [physics]; Mechanics [physics.med-ph]; Mechanics of materials [physics.class-ph]; Engineering Sciences [physics]; Chemical and Process Engineering

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, 2020, 162, pp.106-113. ⟨10.1016/j.carbon.2020.02.027⟩. ⟨hal-02616747⟩