|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Advanced Characterization Techniques for Quantifying and Modeling Deformation
||Evolution of Sigma Phases in 347H Stainless Steels Subjected to Isothermal Aging at 750 oC
||Qing-Qiang Ren, Yukinori Yamamoto, Michael Brady, Jonathan Poplawsky
|On-Site Speaker (Planned)
Sigma phase is an intermetallic compound commonly found in stainless steels after long-term services at elevated temperatures, which damages both mechanical properties and corrosion resistance. We performed SEM, FIB, and APT characterization to identify the sigma phase composition and size evolution in 347H stainless steels for up to 10,000 h aging at 750 oC. The results show that the sigma phase nucleates after ~336h and continues to grow. The sigma compositions at different aging time show little difference in the major elements (Cr and Fe); however, the C concentration decreases from ~0.14 at.% after 336h aging to ~0.05 at.% after >1008h aging. The compositional evolution also reveals the growth mode of sigma phase, which sheds lights on how it can be avoided. APT was performed at ORNL’s CNMS, a US DOE office of science user facility. Research sponsored by US DOE, Office of Fossil Energy and Carbon Management eXtremeMAT program.
||Characterization, Phase Transformations, Iron and Steel