Effect of Hydrogen Content on the Microstructure, Mechanical Properties, and Fracture Mechanism of Low-Carbon Lath Martensite Steel
Boris Yanachkov,
Yana Mourdjeva,
Kateryna Valuiska,
Vanya Dyakova,
Krasimir Kolev,
Julieta Kaleicheva,
Rumyana Lazarova,
Ivaylo Katzarov
Affiliations
Boris Yanachkov
Institute of Metal Science, Equipment, and Technologies with Center of Hydro- and Aerodynamics “Acad. A. Balevski” at the Bulgarian Academy of Sciences, 67 “Shipchenski prohod”, 1574 Sofia, Bulgaria
Yana Mourdjeva
Institute of Metal Science, Equipment, and Technologies with Center of Hydro- and Aerodynamics “Acad. A. Balevski” at the Bulgarian Academy of Sciences, 67 “Shipchenski prohod”, 1574 Sofia, Bulgaria
Kateryna Valuiska
Institute of Metal Science, Equipment, and Technologies with Center of Hydro- and Aerodynamics “Acad. A. Balevski” at the Bulgarian Academy of Sciences, 67 “Shipchenski prohod”, 1574 Sofia, Bulgaria
Vanya Dyakova
Institute of Metal Science, Equipment, and Technologies with Center of Hydro- and Aerodynamics “Acad. A. Balevski” at the Bulgarian Academy of Sciences, 67 “Shipchenski prohod”, 1574 Sofia, Bulgaria
Krasimir Kolev
Institute of Metal Science, Equipment, and Technologies with Center of Hydro- and Aerodynamics “Acad. A. Balevski” at the Bulgarian Academy of Sciences, 67 “Shipchenski prohod”, 1574 Sofia, Bulgaria
Julieta Kaleicheva
Institute of Metal Science, Equipment, and Technologies with Center of Hydro- and Aerodynamics “Acad. A. Balevski” at the Bulgarian Academy of Sciences, 67 “Shipchenski prohod”, 1574 Sofia, Bulgaria
Rumyana Lazarova
Institute of Metal Science, Equipment, and Technologies with Center of Hydro- and Aerodynamics “Acad. A. Balevski” at the Bulgarian Academy of Sciences, 67 “Shipchenski prohod”, 1574 Sofia, Bulgaria
Ivaylo Katzarov
Institute of Metal Science, Equipment, and Technologies with Center of Hydro- and Aerodynamics “Acad. A. Balevski” at the Bulgarian Academy of Sciences, 67 “Shipchenski prohod”, 1574 Sofia, Bulgaria
The effect of hydrogen content on the microstructure, mechanical properties, and fracture mechanisms of low-carbon lath martensitic steel was investigated using both experimental methods and atomistic modeling. Tensile testing revealed a transition in the fracture behavior with increases in hydrogen concentration. Specifically, at a hydrogen content of 0.44 wppm, a shift from transgranular to intergranular fractures was observed. The most probable cause of hydrogen embrittlement was identified to be HELP-mediated HEDE. As the hydrogen concentration increased, the dislocation density in close-packed planes, such as (111) and (100), was found to rise. The key differences between the hydrogen-free and hydrogen-charged specimens were the localization and density of dislocations, as well as the change in the distribution of slip bands. Atomistic modeling supported these experimental findings, showing that “quasi-cleavage” cracks predominantly initiate at block boundaries with higher local hydrogen accumulation. These results underscore the significant role of hydrogen in modifying both the microstructural characteristics and fracture behavior of low-carbon martensitic steel, with important implications for its performance in hydrogen-rich environments.
