Micro/meso-scale computational study of dislocation-stacking-fault tetrahedron interactions in copper
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Enrique Martı´nez Instituto Madrilen~o de Estudios Avanzados en Materiales, 28040 Madrid, Spain
Hyon-Jee Lee and Brian D. Wirth University of California at Berkeley, Berkeley, California 94720 (Received 12 May 2009; accepted 27 July 2009)
In a carbon-free economy, nuclear power will surely play a fundamental role as a clean and cost-competitive energy source. However, new-generation nuclear concepts involve temperature and irradiation conditions for which no experimental facility exists, making it exceedingly difficult to predict structural materials performance and lifetime. Although the gap with real materials is still large, advances in computing power over the last decade have enabled the development of accurate and efficient numerical algorithms materials simulations capable of probing the challenging conditions expected in future nuclear environments. One of the most important issues in metallic structural materials is the degradation of their mechanical properties under irradiation. Mechanical properties are intimately related to the glide resistance of dislocations, which can be increased severalfold due to irradiation-produced defects. Here, we present a combined multiscale study of dislocation-irradiation obstacle interactions in a model system (Cu) using atomistic and dislocation dynamics simulations. Scaling laws generalizing material behavior are extracted from our results, which are then compared with experimental measurements of irradiation hardening in Cu, showing good agreement.
I. INTRODUCTION
Renewed interest in nuclear power systems as a greenhouse-gas-emission-free source of energy has revived research on materials properties under irradiation.1–3 Almost all the concept designs proposed involve neutron dose rates and temperatures for which no experimental facility exists at present. This has again placed computer simulation at the forefront of research in this area, underwritten by more than two decades of experience and the advent of petascale computation capabilities.4 However, although significant progress has been and is being done, the gap between computer simulations and real nuclear materials is still far from being closed. One of the most pressing concerns regarding nuclear materials is the degradation of their mechanical properties after prolonged neutron exposure, which may limit component performance and/or lifetime. The mechanical properties of metallic structural materials are intimately related to the behavior dislocations, specifically the resistance to their free glide. Irradiation-produced defects can increase this a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2009.0424
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http://journals.cambridge.org
J. Mater. Res., Vol. 24, No. 12, Dec 2009 Downloaded: 21 Mar 2015
resistance severalfold, depending on defect type and size, and dislocation character and length. In face-centered cubic (fcc) materials, these effects manifest themselves on engineering stress–strain curves as a yield stress increase (hardening) and ductility los
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