A multi-scale algorithm for dislocation creep at elevated temperatures

Dislocation creep at elevated temperatures plays an important role for plastic deformation in crystalline metals. When using traditional discrete dislocation dynamics (DDD) to capture this process, we often need to update the forces on N dislocations involving similar to N-2 interactions. In this letter, we introduce a multi-scale algorithm to speed up the calculations by dividing a sample of interest into sub-domain grids: dislocations within a characteristic area interact following the conventional way, but their interaction with dislocations in other grids are simplified by lumping all dislocations in another grid as a super one. Such a multi-scale algorithm lowers the computational load to similar to N-1.5. We employed this algorithm to model dislocation creep in Al-Mg alloy. The simulation leads to a power-law creep rate in consistent with experimental observations. The stress exponent of the power-law creep is a resultant of dislocations climb for similar to 5 and viscous dislocations glide for similar to 3. (C) 2021 Published by Elsevier Ltd on behalf of The Chinese Society of Theoretical and Applied Mechanics.