Helium implantation effects on the tensile response of nano-twinned copper
J Sun and Q Li and HY Tang and HW Zhang and HF Ye and YG Zheng, JOURNAL OF NUCLEAR MATERIALS, 541, 152426 (2020).
Metallic materials used in fission and fusion reactors will internally accumulate numerous lattice defects and bubbles because of high radiation. An in-depth understanding on the influence of bubbles is significant to the safety and life assessment of relevant engineering equipment. Here, molecular dynamics simulations are performed to investigate the effects of twin boundary (TB) spacing, inner-bubble pressure, temperature and bubble number density on uniaxial tensile deformation behaviors of helium bubbles implanted nano-twinned copper (nt-Cu). Simulation results reveal that the TB can significantly enhance the strength of nt-Cu because of the Hall-Petch effect. The increase of inner-bubble pressure reduces the critical stress of dislocation emission, which in turn reduces the yield stress. High temperature softens the models and increases the inner-bubble pressure. The weaken effect of pressure component is remarkable in the yield strength, while that has little impact on the elastic modulus and the average flow stress. In addition, the larger bubble number density is accompanied by the lower elastic modulus, yield stress and average flow stress. The present findings provide valuable suggestions for upgrading the design and fabrication of high radiation-resistant metallic materials. (C) 2020 Elsevier B.V. All rights reserved.
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