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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
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Magnetostructural Transition Kinetics in Shocked Iron
Michael P Surh1, Lorin X Benedict1, Babak Sadigh1
1Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
Physical Review Letters
|September 3, 2016
Summary
Thermal magnetic disorder impacts iron phase transitions. While bulk displacement barriers remain high, the [001] boundary shows instability, suggesting magnetic and structural order are linked.
Area of Science:
- Condensed matter physics
- Materials science
- Computational physics
Background:
- The iron α-ε phase transition is crucial for understanding material behavior under extreme conditions.
- Thermal magnetic disorder is a known factor influencing material properties, but its specific role in phase transitions requires further investigation.
Purpose of the Study:
- To investigate the influence of thermal magnetic disorder on the kinetics of the iron (Fe) alpha (α) to epsilon (ε) phase transition.
- To analyze the energy barriers for martensitic displacement in α-Fe under shock conditions.
Main Methods:
- Implementation of a generalized Heisenberg model to simulate the Fe α-ε transition.
- Analysis of the effects of shock compression and magnetic disorder on structural kinetics.
Main Results:
- A significant barrier to bulk martensitic displacement was observed in α-Fe shocked past the phase line.
- The energy barrier was substantially reduced at the [001] α-ε boundary.
- These findings align with observations of overdriving to metastable α and suggest structural instability at the [001] boundary.
Conclusions:
- The study highlights the complex interplay between magnetic and structural order during the Fe α-ε transition under shock.
- Concurrent treatment of magnetic and structural order is likely necessary to fully reconcile observed phenomena.
- The findings provide insights into the mechanisms governing shock-induced phase transformations in iron.
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