Colloquium: Yang Su (ASM)

30 mei 2022 09:00 - Locatie: LECTURE ROOM D, FACULTY OF AEROSPACE ENGINEERING, KLUYVERWEG 1, DELFT | Zet in mijn agenda

Self-Healing Behavior in 12Cr Steels

Self-healing of creep-induced damage in the newly designed 12Cr self-healing ferritic steels is studied. Two kinds of W-induced self-healing steel with different precipitation driving forces of W-rich Laves phase designed by a computational model are investigated, namely fast self-healing steel (FSHS) and slow self-healing steel (SSHS). FSHS is expected to show the self-healing phenomenon under the testing condition of this study, while SSHS not. Creep tests were performed on bone-shaped samples with constant stresses ranging from 100 to 260 MPa at 550 °C. The creep data were analyzed, and microstructural investigations were conducted on fracture surfaces, the stress-affected region, and the stress-free region. The result shows that although the creep-resistant properties are comparable with traditional 12Cr steels, expected healing phenomena are not found in FSHS under current conditions due to the absence of creep damage. The behavior of Laves phase does not correspond to the design objectives' expectations.

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