We have recently reported on the measurement of thermal conductivity in a series of ion irradiated materials via time domain thermoreflectance (TDTR), demonstrating TDTR as an effective means for the characterization of radiation induced damage. Due to the relatively high modulation frequencies and time domain experimental data in a TDTR experiment, this measurement technique offers the unique ability to characterize radiation-induced damage of materials at varying depths under the surface via quantification of the thermal conductivity. This work, in which Ramez Cheaito was the first author, was recently published in the Journal of Materials Research (J. Mat. Res. 30 1403 – 1412 (2015)) – Congrats Ramez!!
Abstract
The progressive build up of fission products inside different nuclear reactor components can lead to significant damage of the constituent materials. We demonstrate the use of time-domain thermoreflectance (TDTR), a nondestructive thermal measurement technique, to study the effects of radiation damage on material properties. We use TDTR to report on the thermal conductivity of optimized ZIRLO, a material used as fuel cladding in nuclear reactors. We find that the thermal conductivity of optimized ZIRLO is 10.7 +/- 1.8 W/m/K at room temperature. Furthermore, we find that the thermal conductivities of copper– niobium nanostructured multilayers do not change with helium ion irradiation doses of 1015 cm2 and ion energy of 200 keV, demonstrating the potential of heterogeneous multilayer materials for radiation tolerant coatings. Finally, we compare the effect of ion doses and ion beam energies on the measured thermal conductivity of bulk silicon. Our results demonstrate that TDTR can be used to quantify depth dependent damage.
This work was performed in part at the Center for Atomic, Molecular, and Optical Science (CAMOS) at the University of Virginia. P. E. H. recognizes support from the Naval Research Young Investigator Program (Grant No. N00014-13-4-0528). Authors acknowledge Evans Analytical Group for TEM data. We are appre- ciative of funding through Sandia National Laboratories. Sandia National Laboratories is a multiprogram labora- tory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corpo- ration, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE- AC04-94AL85000.
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