Modeling thermal spike driven reactions at low temperature and application to zirconium carbide radiation damage

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:410

Article

Ulmer, Christopher J.¹  Motta, Arthur T.¹ 

[1] Penn State Univ, Dept Mech & Nucl Engn, University Pk, PA 16802 USA

关键词: Rate theory;    Ion irradiation;    Zirconium carbide;    Thermal spike;    Athermal;   

DOI  :  10.1016/j.nimb.2017.08.015

来源: Elsevier

【 摘 要 】

The development of TEM-visible damage in materials under irradiation at cryogenic temperatures cannot be explained using classical rate theory modeling with thermally activated reactions since at low temperatures thermal reaction rates are too low. Although point defect mobility approaches zero at low temperature, the thermal spikes induced by displacement cascades enable some atom mobility as it cools. In this work a model is developed to calculate athermal reaction rates from the atomic mobility within the irradiation-induced thermal spikes, including both displacement cascades and electronic stopping. The athermal reaction rates are added to a simple rate theory cluster dynamics model to allow for the simulation of microstructure evolution during irradiation at cryogenic temperatures. The rate theory model is applied to in-situ irradiation of ZrC and compares well at cryogenic temperatures. The results show that the addition of the thermal spike model makes it possible to rationalize microstructure evolution in the low temperature regime. (C) 2017 Elsevier B.V. All rights reserved.

【 授权许可】

Free