Abstract
Real-time in situ neutron diffraction was used to characterize the crystal structure evolution in a transformation-induced plasticity (TRIP) sheet steel during annealing up to 1000◦C and then cooling to 60◦C. Based on the results of full-pattern Rietveld refinement, critical temperature regions were determined in which the transformations of retained austenite to ferrite and ferrite to high-temperature austenite during heating and the transformation of austenite to ferrite during cooling occurred, respectively. The phase-specific lattice variation with temperature was further analyzed to comprehensively understand the role of carbon diffusion in accordance with phase transformation, which also shed light on the determination of internal stress in retained austenite. These results prove the technique of real-time in situ neutron diffraction as a powerful tool for heat treatment design of novel metallic materials.
| Original language | English |
|---|---|
| Article number | 360 |
| Journal | Crystals |
| Volume | 8 |
| Issue number | 9 |
| DOIs | |
| State | Published - Sep 2018 |
Funding
Acknowledgments: The neutron scattering experiment was carried out at the Spallation Neutron Source (SNS), which is the U.S. Department of Energy (DOE) user facility at the Oak Ridge National Laboratory, sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences. D.Y. thanks the support of the ORNL-UTK SWC IAP program. The authors thank M.J. Frost from SNS for the technical support. L.H. would like to thank United States Steel Corporation for the permission to publish the data in this paper.
| Funders | Funder number |
|---|---|
| Office of Basic Energy Sciences | |
| Scientific User Facilities Division | |
| U.S. Department of Energy |
Keywords
- Annealing
- Carbon concentration
- In situ neutron diffraction
- Phase transformation
- Thermal expansion
- Trip steel