SKM 2023 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 9: Topical Session: Fundamentals of Fracture – Interface Fracture
MM 9.7: Vortrag
Montag, 27. März 2023, 17:45–18:00, SCH A 216
Abnormal internal oxidation of grain boundary and its cracking behavior under mechanical stress in an FeCr alloy — •Kuan Ding1, Xiao Shen2, Siyuan Zhang3, Jiejie Li4, Enrico Bruder1, Jianjun Li4, Wenwen Song2, Karsten Durst1, James P. Best3, and Xufei Fang1 — 1Department of Materials and Earth Sciences, TU Darmstadt, 64287 Darmstadt, Germany — 2Steel Institute (IEHK), RWTH Aachen University, 52072 Aachen, Germany — 3Max-Planck-Institut für Eisenforschung GmbH, 40237 Düsseldorf, Germany — 4School of Mechanical and Electrical Engineering, Central South University, 410083 Changsha, China
FeCr-based Ferritic stainless steels display great potential for applications as interconnects of solid oxide fuel cells at temperatures below 800 °C. Cr provides good oxidation resistance by forming a protective oxide layer to prevent the substrate from exposing to corrosive environment. However, grain boundaries (GBs) act as fast diffusion paths, and internal oxidation along the GB can form brittle oxide, which is prone to cracking under mechanical stresses. In this work, we investigated the abnormal growth of GB oxide at 600 °C in air and its impact on GB cracking in Fe-15wt.%Cr alloy. The microstructure and chemical characterization of the abnormal GB oxide revealed a layer of chromium oxide forming with a large penetration depth. To study the mechanical response, we conducted both ex-situ and in-situ micromechanical tests and simulation and observed the cracking behavior of the abnormal GB oxide. Our finding provides insights into improving the oxidation and fracture resistance through material design.