Abstract
Nuclear graphite contains defects spanning from nanoscale basal cracks to sub-mm scale voids. This study aims to establish an experimental method to investigate pre-existing defects and 3-D crack growth inside nuclear graphite, NBG-18. Three-point bending tests were performed on single-edge notched beam specimens with and without coupling with micro-CT. The fracture toughness was measured to be 1.17 ± 0.06 MPa m. Cracks were observed to initiate from the pores and thermal cracks on the edge of the notch and then deflect or twist to grow along the pre-existing defects. Crack bridging, deflection, and twisting were the primary toughening mechanisms. The crack resistance curve exhibited a trend of rising-plateau-rising that can be related to the interaction of crack front and the pre-existing defects. The results highlight the capability of laboratory micro-CT-based experimental method for the visualization of multi-scale defect interactions, which remains to be a challenge in the characterization of nuclear graphite. Graphical abstract: [Figure not available: see fulltext.].
Original language | English (US) |
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Pages (from-to) | 1984-1993 |
Number of pages | 10 |
Journal | Journal of Materials Research |
Volume | 38 |
Issue number | 7 |
DOIs | |
State | Published - Apr 14 2023 |
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering