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Lecture

WEB Dislocation-solute interaction in alloys: phase-field and atomistic modeling compared with experiments

Wednesday (23.09.2020)
15:15 - 15:30 M: Modelling and Simulation 2
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In many engineering alloys, material chemistry interacts strongly with defects processes governing their material behavior. On the one hand, the presence of defects can result in spatial variations in chemical composition and so heterogeneous material properties. On the other hand, spatial variation in material properties can have a strong effect on defect processes, e.g., dislocation glide. This strong two-way coupling and its effect on material behavior is modeled in the current work with the help of a general phase-field-based methodology [1] for the chemomechanics of multiphase, multicomponent systems. This methodology has been applied to formulate models for interaction of chemistry and defects in a number of alloy systems, e.g., Ni-Al-Co in [2], or Pt-Au in the current work. The corresponding energy models are calibrated employing information from DFT, atomistics and / or CALPHAD In particular, this facilitates quantitatively accurate modeling of dislocation core size and dislocation transformation pathways. The resulting atomistic phase-field chemomechanical models are capable for example of predicting solute segregation to defect structures (e.g., dislocations, grain boundaries) and general solute-defect interaction. Furthermore, diffusive molecular dynamics (DMD) [3] is also employed to model solute diffusion and its interaction with defects at atomistic scales. In the current work, phase-field simulation results for the binary system Pt-Au are compared with analogous DMD and experimental results obtained with the help of atom probe tomography and precession electron diffraction. A number of example comparisons will be presented and discussed.


REFERENCES


[1] Mianroodi, J.R., Shanthraj, P., Kontis, P., Cormier, J., Gault B., Svendsen, B., Raabe, D. Atomistic phase field chemomechanical modeling of solute segregation and dislocation-precipitate interaction in Ni-Al-Co. Acta Materialia, (2019) 175:1–30.

[2] Svendsen, B., Shanthraj, P., Raabe, D. Finite-deformation phase-field chemomechanics for multi-phase, multicomponent solids. Journal of the Mechanics and Physics of Solilds (2018) 112: 619–636.

[3] Mendez, J., Ponga, M. MXE: A package for simulating long-term diffusive mass transport phenomena in nanoscale systems. arXiv:1910.01235v1 (2019).

 

Speaker:
Dr. Jaber Rezaei Mianroodi
RWTH Aachen University
Additional Authors:
  • Dr. Pratheek Shanthraj
    The University of Manchester
  • Dr. Xuyang Zhou
    Max-Planck-Institut für Eisenforschung GmbH
  • Prof. Gregory B. Thompson
    The University of Alabama
  • Prof. Bob Svendsen
    RWTH Aachen University