Molecular Dynamic Dimulation of Energy and Structural Stability on Twist Grain Boundary in Bicrystal Copper

Abstract

The energies and microstructures of <001> and <111> twist grain boundary (GB) planes in bicrystal copper with different twist angles were simulated by molecular dynamic (MD). The simulation results indicated that Σ5 and Σ3 twist GBs were stable GB structures of (001) and (111) planes respectively. Compared energies of both kinds of boundaries, <111> twist GBs were more stable. Furthermore, Σ3 GB had the lowest GB energy of all <111> twist GBs. Therefore, Σ3 <111> twist GB had the priority to form on (111) plane and was the most stable GB structure in this simulation that partly explained the reason why Σ3 GBs had high probability to appear in polycrystalline materials. The two more stable GB structures of <001> and <111> twist GBs are both low Σ value coincidence site lattice (CSL) special GBs, which directly proved that lower energy and more stable GBs could provide more GB failure resistance.