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Title: Dynamics of Helium-Loaded Grain Boundaries under Shear Deformation in α-Fe

The defects produced in collision cascades will interact with microstructural features in materials, such as GBs and dislocations. The coupled motion of GBs under stress has been widely observed in simulations and experiments. Two symmetric tilt GBs with a common <110> tilt axis (Σ3 and Σ11) in bcc iron are used to investigate the coupled motion of GBs under shear deformation. Also, we have explored the effect of self-interstitial atoms (SIAs) loading on the GB motion, with different concentrations of interstitials randomly inserted around the GB plane. The simulation results show that the interstitial loading reduces the critical stress of the GB coupled motion for the Σ3 GB. Furthermore, the interstitials and vacancies are inserted randomly at the GB plane and at a distance of 1 nm away from the GB plane, respectively, to understand the self-healing mechanism of GBs under stress. The behavior of the defect-loaded GBs depends on the GB structure. The loaded interstitials in the Σ3 GB easily form <111> interstitial clusters that do not move along with the GB. The vacancies in the Σ3 GB impede the GB motion. However, the interstitials move along with the Σ11 GB and annihilate with vacancies when the GB movesmore » into the vacancy-rich region, leading to the self-healing and damage recovery of the Σ11 GB.« less
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Related Information: Fusion Materials Semiannual Progress Report for the Period Ending December 31, 2013, 55; DOE/ER-0313/55:112-118
Oak Ridge National Lab, Oak Ridge , TN, United States(US).
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Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
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United States