Evaluation of Mechanical Properties of Σ5(210)/[001] Tilt Grain Boundary with Self-Interstitial Atoms by Molecular Dynamics Simulation

Abstract

Grain boundary (GB) can serve as an efficient sink for radiation-induced defects, and therefore nanocrystalline materials containing a large fraction of grain boundaries have been shown to have improved radiation resistance compared with their polycrystalline counterparts. However, the mechanical properties of grain boundaries containing radiation-induced defects such as interstitials and vacancies are not well understood. In this study, we carried out molecular dynamics simulations with embedded-atom method (EAM) potential to investigate the interaction of Σ5(210)/[001] symmetric tilt GB in Cu with various amounts of self-interstitial atoms. The mechanical properties of the grain boundary were evaluated using a bicrystal model by applying shear deformation and uniaxial tension. Simulation results showed that GB migration and GB sliding were observed under shear deformation depending on the number of interstitial atoms that segregated on the boundary plane. Under uniaxial tension, the grain boundary became a weak place after absorbing self-interstitial atoms where dislocations and cracks were prone to nucleate.

Effect of symmetrical and asymmetrical tilt grain boundaries on radiation-induced defects in zirconium

“…It has already been established by researchers that grain boundary (GB) structures, act as sinks for radiation-induced point defects (i.e. vacancy and interstitials) [10][11][12][13][14][15][16][17][18][19][20][21][22]. The annihilation of point defects by the GB further prevents the clustering of these defects, which in turn prevents unfavourable microstructural changes leading to structural failures.…”

Atomistic investigation of the impact of phosphorus impurities on the tungsten grain boundary decohesion

“…The effects of free surfaces were avoided by using a simulation cell that was periodic in all directions, while maintaining a minimum separation of 75 Å between neighbouring GBs, which ensured that no interaction occurred between them along the 𝑧−direction. With the in-plane dimensions of the setup being ∼45 Å × 45 Å, constrained boundary conditions that corresponded to zero lateral strain [63][64][65][66][67][68][69] were applied in the in-plane directions, i.e. 𝜖 𝑥𝑥 = 𝜖 𝑦𝑦 = 0.…”

“…The adopted uniaxial-strain controlled setup that utilizes periodic lateral boundaries with prescribed zero strain has been extensively used for previous GB mode I tensile modelling, see e.g. [63][64][65][66][67][68][69]. Although the periodic boundaries restrict dislocation nucleation, the prescribed zero lateral strains reflect the multiaxial stress state that is expected to emerge at crack-tips under plane strain loading, or as a result of microstructural constraints imposed by the neighbouring grains, GBs or triple junctions.…”

Structure and Migration Mechanisms of Small Vacancy Clusters in Cu: A Combined EAM and DFT Study

“…However, the vacancy clustering mechanisms are not fully understood [24]. In particular, grain boundaries (GBs) can serve as efficient sinks for point defects in metals [33][34][35]. Reports have suggested how GBs can reduce the formation, binding, and segregation energies of nearby vacancies [36,37].…”