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Uncertainty quantification of long-timescale evolution in precipitation-strengthened alloys

Supervisor: Dr Peter Brommer (School of Engineering)

Long-time evolution of microstructures is a formidable simulation challenge covering timescales from femtoseconds up to seconds and beyond. The motion of atoms is mainly characterised by thermal vibrations around their equilibrium positions, with rare events, when the system transitions between two different configurations, driving the evolution. The kinetic Monte Carlo code kART [1] identifies those rare transitions, calculates their relative rates and then evolves the system by selecting a random pathway along states connected by those rare events.
Cu-Ni-Si alloys combine high strengths and high electrical conductivities. They derive their strength from NiSi precipitates forming in a copper matrix, which inhibit dislocation motion [2]. The ageing process that forms the precipitates is inaccessible to classical molecular dynamics simulation.
In this project, the ageing process in precipitation-hardened alloys will be studied using kinetic Monte Carlo based on atomic interaction models fitted to electronic structure calculations [3]. Of particular interest is the robustness of predicted evolution pathways, as small errors in the predicted barriers can have severe impact on rates.

Precipitates in matrix

References
  1. L.K. BĂ©land, P. Brommer, et al., Phys. Rev. E, 84, 046704 (2011) doi:10.1103/PhysRevE.84.046704
  2. S. Hocker, H. Lipp, et al., J. Chem. Phys., 149, 24701 (2018) doi:10.1063/1.5029887
  3. P. Brommer, A. Kiselev, et al., Modell. Simul. Mater. Sci. Eng., 23, 074002 (2015) doi:10.1088/0965-0393/23/7/074002