Formation of delta ferrite in 9 wt.% Cr steel investigated by in-situ X-ray diffraction using synchrotron radiation
- Graz University of Technology
- Lawrence Livermore National Laboratory (LLNL)
- ORNL
- Massachusetts Institute of Technology (MIT)
In situ X-ray diffraction measurements using high energy synchrotron radiation were performed to monitor in real time the formation of delta ferrite in a martensitic 9 wt.% chromium steel under simulated weld thermal cycles. Volume fractions of martensite, austenite and delta ferrite were measured as a function of temperature at a 10 C s-1 heating rate to 1300 C and subsequent cooling to room temperature. At the peak temperature, the delta ferrite concentration rose to a level of 19%, of which 17% transformed back to austenite on subsequent cooling. The final microstructure after this single thermal cycle consisted of newly formed martensite with 4% of retained austenite and 2% of retained delta ferrite.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 992531
- Journal Information:
- Metallurgical and Materials Transactions A, Vol. 41A, Issue 10; ISSN 1073-5623
- Country of Publication:
- United States
- Language:
- English
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