Co-authors: Chaitanya Deo^1, Remi Dingreville^2
1 = Georgia Institute of Technology, Department of Nuclear and Radiological Engineering, Atlanta, GA
2 = Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM
Reduced-order Atomistic Method for Simulating High Dose Irradiation in Metal
Atomistic modeling of irradiation damages through displacement cascades is deceptively nontrivial. Due to the high energy, high velocity nature of the atom collisions, individual cascade simulations can become very computational expensive and ill-suited for size and dose upscaling. In order to examine microstructural evolutions, and mechanical property changes due to defect accumulation, alternative methods of modeling radiation defect accumulation are needed. Originally developed for application in ceramic materials, the Frenkel Pair Accumulation (FPA) method1 generates point defect pairs by directly displacing atoms from its initial lattice site. The applicability of method is somewhat limited to metallic/dense materials, as it does not capture the important cascade process known as the thermal spike2. The presence of the thermal spikes has shown to be influence both point defect clustering3 and sequential cascade overlaps4. Instead, using FPA as the basis and incorporating a reduced-order approximation for thermal spike, a new method of modeling radiation damage is developed. By adopting the athermal recovery corrected (arc) formalisms2, the new arc Damage Insertion (arc-DI) method is able to predict and replicate radiation events across a wide range of recoil energy. Using Cu and Nb as the case studies, arc-DI is verified against standard displacement cascades. Example applications for simulating high energy cascade fragmentation and large dose ion-bombardment are also provided for demonstration. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy National Nuclear Security Administration under contract DENA0003525.
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2 Nordlund, Kai, et al. "Improving atomic displacement and replacement calculations with physically realistic damage models." Nature communications 9.1 (2018): 1084.
3 Calder, A. F., et al. "On the origin of large interstitial clusters in displacement cascades." Philosophical Magazine 90.7-8 (2010): 863-884.
4 Sand, A. E., et al. "Defect structures and statistics in overlapping cascade damage in fusion-relevant bcc metals." Journal of Nuclear Materials 511 (2018): 64-74.