TY - JOUR

T1 - Hydrogen trapping and desorption affected by ferrite grain boundary types in shielded metal and flux-cored arc weldments with Ni addition

AU - Moshtaghi, Masoud

AU - Loder, Bernd

AU - Safyari, Mahdieh

AU - Willidal, Thomas

AU - Hojo, Tomohiko

AU - Mori, Gregor Karl

N1 - Publisher Copyright: © 2022 Hydrogen Energy Publications LLC

PY - 2022/5/18

Y1 - 2022/5/18

N2 - Hydrogen trapping behavior and diffusion induced by the microstructure of shielded metal and flux-cored arc weldments (SMAW and FCAW) were characterized using a combination of high-resolution microstructural characterization methods, hydrogen trap site studies, and a modeling technique. H trapping by HAGBs that was found by TDS was confirmed by NanoSIMS with a cryogenic stage. Cellular automaton modeling results showed that in grain sizes smaller than a critical grain size, the hydrogen diffusion coefficient decreases with decreasing grain size, indicating that H trapping dominates short-circuit diffusion mechanism along high-angle grain boundaries (HAGBs). These results firstly show that smaller grain size and high HAGB density in the FCAW specimen results in a lower H diffusion coefficient and higher density of relatively strong HAGB traps, and a lower total desorbed hydrogen content in the FCAW specimen. Also, it was suggested that the fraction of acicular ferrite grains can define the HAGB content in the alloy, and can be a determinant factor in the behavior of weldments in H-containing media.

AB - Hydrogen trapping behavior and diffusion induced by the microstructure of shielded metal and flux-cored arc weldments (SMAW and FCAW) were characterized using a combination of high-resolution microstructural characterization methods, hydrogen trap site studies, and a modeling technique. H trapping by HAGBs that was found by TDS was confirmed by NanoSIMS with a cryogenic stage. Cellular automaton modeling results showed that in grain sizes smaller than a critical grain size, the hydrogen diffusion coefficient decreases with decreasing grain size, indicating that H trapping dominates short-circuit diffusion mechanism along high-angle grain boundaries (HAGBs). These results firstly show that smaller grain size and high HAGB density in the FCAW specimen results in a lower H diffusion coefficient and higher density of relatively strong HAGB traps, and a lower total desorbed hydrogen content in the FCAW specimen. Also, it was suggested that the fraction of acicular ferrite grains can define the HAGB content in the alloy, and can be a determinant factor in the behavior of weldments in H-containing media.

UR - http://www.scopus.com/inward/record.url?scp=85130431744&partnerID=8YFLogxK

U2 - 10.1016/j.ijhydene.2022.04.260

DO - 10.1016/j.ijhydene.2022.04.260

M3 - Article

VL - 47

SP - 20676

EP - 20683

JO - International Journal of Hydrogen Energy

JF - International Journal of Hydrogen Energy

SN - 0360-3199

IS - 47

ER -