Download presentation
Presentation is loading. Please wait.
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
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.