Abstract
Oxidation of nuclear graphites produces microstructural changes that affect the elastic moduli of these materials. It is widely accepted that the primary effect of oxidation is to increase porosity, but the related effect on the moduli cannot be explained satisfactorily by simply noting changes to porosity. In this work, models describing the elastic moduli of porous, polycrystalline graphite materials are developed to interpret experimental determinations of Young's modulus and shear modulus in two grades of nuclear graphite – IG-110 and NBG-18 – that were oxidized to produce varying levels of porosity. Experimental measurements were carried out using laser-based ultrasonic methods and were interpreted successfully using models that take into account the effects of preferential oxidation of different elements of the graphite microstructure. The results indicate the importance of the processes that lead to increased porosity since these can heavily influence the nature of the resulting structure-property relationships.
Original language | English |
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Pages (from-to) | 304-315 |
Number of pages | 12 |
Journal | Carbon |
Volume | 141 |
DOIs | |
State | Published - Jan 2019 |
Funding
The authors gratefully acknowledge the support of the U.S. Department of Energy (DOE) through the Nuclear Energy University Program (NEUP) Contract No. 00118687 . Research at ORNL was performed collaboratively with Johns Hopkins University under the DOE Work for Others (WFO) Program. The authors gratefully acknowledge the support of the U.S. Department of Energy (DOE) through the Nuclear Energy University Program (NEUP) Contract No. 00118687. Research at ORNL was performed collaboratively with Johns Hopkins University under the DOE Work for Others (WFO) Program.