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Princeton Materials Institute (PMI)

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Presentation on theme: "Princeton Materials Institute (PMI)"— Presentation transcript:

1 Princeton Materials Institute (PMI)
Temperature Dependence of Grain Boundary Migration in 3-D Hao Zhang David J. Srolovitz Princeton University Princeton Materials Institute (PMI) Acknowledgements Moneesh Upmanyu ORNL Lasar Shvindlerman Russian Academy of Sciences/RWTH Gunther Gottstein RWTH Aachen S. Srinivasan LANL

2 Outline Atomic Simulation Model
Modeling Approach Driving Force Dependence of Migration Recent 3-D Results (Temperature Dependence) Reduced Mobility Grain Boundary Energy Mobility Activation Energy Conclusions

3 Grain Boundary Migration
Absolute reaction rate theory (Turnbull, 1951) Grain growth (capillarity-induced migration)

4 Modeling Approach U-shaped half loop geometry Local velocity
FCC Aluminium <111> Tilt Grain Boundary EAM – Al Periodic along X, Y and Z v(y) Local velocity Steady-state velocity Boundary energy

5 Driving Force Dependence of Migration
Grain Boundary Energy (J/m2) Driving Force k=p/w (nm-1) Migration rate v (ro/t) Reduced Mobility Mgbggb (ao/t) For sufficiently low driving forces : Reduced mobility is independent of driving force (2-D) Migration rate is proportional to driving force (2-D) Grain Boundary Energy is large (3-D)

6 Grain Boundary Migration
S7 Grain Boundary at T=427K

7 M* vs. Misorientation S13 S7 (m4/Js) (deg)

8 Mobility and γ vs. Misorientation
(J/m2) (m4/Js) (deg) (deg)

9 Mobility vs. Misorientation
(m4/Js) (deg)

10 Temperature Dependence of Mobility
Simulation Experiments

11 Activation Energy vs. Misorientation
Simulation S13 S7 experiment Misorientation q (deg) S7 Q (eV) (eV) (deg)

12 Conclusions Reduced mobility shows local maxima at low S7
Mobility shows maxima at low S misorientations Boundary energy exhibits minima at low S misorientations Magnitude of activation energy in simulation << than in experiment Possible reasons: simulations do not represent the true physics impurities


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