Next Article in Journal
Elastic and Dielectric Evaluation of the Piezoelectric Response of Ferroelectrics Using Unpoled Ceramics
Previous Article in Journal
In-Situ Kinetic Investigation of Calcium Aluminate Formation
Open AccessArticle

Fracture Toughness Evaluation and Plastic Behavior Law of a Single Crystal Silicon Carbide by Nanoindentation

1
Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06511, USA
2
Department of Chemical Engineering, Yale University, New Haven, CT 06511, USA
3
Ceramic Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
4
Guangdong University of Technology, Guangzhou 510090, China
*
Author to whom correspondence should be addressed.
Ceramics 2018, 1(1), 198-210; https://doi.org/10.3390/ceramics1010017
Received: 10 July 2018 / Revised: 6 September 2018 / Accepted: 6 September 2018 / Published: 18 September 2018
Nanoindentation-based fracture toughness measurements of ceramic materials like silicon carbide (SiC) with pyramidal indenters are of significant interest in materials research. A majority of currently used fracture toughness models have been developed for Vickers indenters and are limited to specific crack geometries. The validity of the indentation-cracking method for the fracture toughness measurement of single crystal SiC, the elastic-plastic anisotropy and orientation dependence around the c-axis when indented in the <0001> direction is examined using nanoindentation with different pyramidal indenters. The residual impressions are analyzed using scanning electron microscopy to measure the crack lengths and the validity of existing fracture toughness measurement methods and equations is analyzed. A combination of nanoindentation with different pyramidal indenters to produce a wide range of effective strains and finite element simulation is used to extract flow properties of single crystal SiC in the <0001> direction. It is observed that there is no orientation dependence around the c-axis when SiC-6H is indented in the <0001> direction with a Berkovich indenter, i.e., it is transversely isotropic. It is also found that for a Berkovich indenter, the Jang and Pharr model, which is based on the Lawn model for cone/halfpenny cracks, gives approximately constant values at low loads (<1 N), while at higher loads (>1 N), the Laugier model gives constant fracture toughness values. Finite element analysis using equivalent cones is used along with measured hardness values to estimate the yield strength, the work hardening exponents and the stress–strain curve for single crystal SiC-6H in the <0001> direction. View Full-Text
Keywords: silicon carbide; nanoindentation; fracture toughness silicon carbide; nanoindentation; fracture toughness
Show Figures

Figure 1

MDPI and ACS Style

Datye, A.; Schwarz, U.D.; Lin, H.-T. Fracture Toughness Evaluation and Plastic Behavior Law of a Single Crystal Silicon Carbide by Nanoindentation. Ceramics 2018, 1, 198-210.

Show more citation formats Show less citations formats

Article Access Map by Country/Region

1
Back to TopTop