About this Abstract |
Meeting |
2023 TMS Annual Meeting & Exhibition
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Symposium
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Local Ordering in Materials and Its Impacts on Mechanical Behaviors, Radiation Damage, and Corrosion
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Presentation Title |
Observation of Fe and Mn Chemical Ordering in High Mn Steels by Neutron Diffraction |
Author(s) |
Lawrence Cho, Pawan Kathayat, Yuran Kong, John G Speer, Kip O. Findley, Donald W. Brown, Bjorn Clausen, Sven C. Vogel, Samantha K. Lawrence |
On-Site Speaker (Planned) |
Lawrence Cho |
Abstract Scope |
While many austenitic alloys exhibit long-range-ordered phases, e.g. L12 and L’12, Fe-Mn alloys have long been known as chemically disordered solid solutions. Recent studies on Fe-Mn-C alloys have suggested the existence of short-range ordering, but the experimental evidence of ordering reactions in high Mn steels is still lacking in literature. In this study, we investigated ordering reactions in three high Mn (30 wt%) austenitic steels through neutron diffraction, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The neutron diffraction measurements detected, in addition to austenite peaks, extra peaks, which are interpreted to be associated with an L12-type superlattice, i.e. chemical ordering of Fe and Mn. The possible superlattice reflections were not detected in the TEM/XRD analyses because X-ray (or electron) scattering factors for Fe and Mn are similar. In contrast, Fe and Mn have significantly different scattering lengths for neutron diffraction, which explains the observation of the potential superlattice reflections. |
Proceedings Inclusion? |
Planned: |