Grain size dependence of hardness in nanocrystalline silicon carbide

Journal Article · Thu Oct 01 04:00:00 EDT 2020 · Journal of the European Ceramic Society

DOI:https://doi.org/10.1016/j.jeurceramsoc.2020.05.060· OSTI ID:1734868

Pan, Chenlong ^[1]; Zhang, Limin ^[1]; Jiang, Weilin ^[2]; Setyawan, Wahyu ^[2]; Chen, Liang ^[1]; Li, Zhiming ^[1]; Liu, Ning ^[1]; Wang, Tieshan ^[1]

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1. Lanzhou University
2. BATTELLE (PACIFIC NW LAB)

The response of nanocrystalline silicon carbide (nc-SiC) to nanoindentation is investigated using molecular dynamics (MD) simulation. It is found that the hardness of the nc-SiC decreases with decreasing grain size, showing an inverse Hall-Petch relationship. The behavior is primarily attributed to the reduced number of intact covalent bonds with grain refinement. Dislocation nucleation and growth in nc-SiC are strongly suppressed by the grain boundaries (GBs). In addition to the dislocation region in the grains, the indentation-induced amorphization of nanograins proceeds preferentially from the GBs, leading to grain shrinkage until the grains are fully amorphized. The results provide an improved understanding of the mechanical properties in nc-SiC and other nanostructured covalent materials.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1734868
• Report Number(s): PNNL-SA-151492
• Journal Information: Journal of the European Ceramic Society, Journal Name: Journal of the European Ceramic Society Journal Issue: 13 Vol. 40
• Country of Publication: United States
• Language: English

Related Subjects

Hardness
amorphization
molecular dynamics
nanocrystalline ceramics
Silicon Carbide