TY - JOUR

T1 - Combined thermal desorption spectroscopy, hydrogen visualization, HRTEM and EBSD investigation of a Ni–Fe–Cr alloy

T2 - The role of hydrogen trapping behavior in hydrogen-assisted fracture

AU - Moshtaghi, Masoud

AU - Safyari, Mahdieh

AU - Mori, Gregor Karl

N1 - Publisher Copyright: © 2022 The Authors

PY - 2022/7/19

Y1 - 2022/7/19

N2 - The role of hydrogen trapping behavior in hydrogen-assisted cracking in a Ni–Fe–Cr alloy has been investigated using thermal desorption spectroscopy (TDS), hydrogen visualization, and high-resolution microstructural characterization methods. The results indicate that hydrogen resides at interstitial lattice sites, dislocations, and vacancies with the ascending order of the desorption activation energies. This study firstly shows that hydrogen is trapped reversibly at dislocations including misfit dislocations at the austenite/δ phase interface, and deformation-induced dislocations. The hydrogen trapping behavior is proved by TDS and hydrogen visualization technique. The weakly trapped hydrogen at dislocations provides sufficient hydrogen to build up a required critical hydrogen concentration at potential flaws for crack nucleation and to activate hydrogen enhanced decohesion mechanism. Further, it was found that δ phase precipitation exacerbates the hydrogen embrittlement sensitivity. For the first time, evidence for hydrogen transport by dislocations in a Ni-based alloy is observed by the hydrogen visualization technique.

AB - The role of hydrogen trapping behavior in hydrogen-assisted cracking in a Ni–Fe–Cr alloy has been investigated using thermal desorption spectroscopy (TDS), hydrogen visualization, and high-resolution microstructural characterization methods. The results indicate that hydrogen resides at interstitial lattice sites, dislocations, and vacancies with the ascending order of the desorption activation energies. This study firstly shows that hydrogen is trapped reversibly at dislocations including misfit dislocations at the austenite/δ phase interface, and deformation-induced dislocations. The hydrogen trapping behavior is proved by TDS and hydrogen visualization technique. The weakly trapped hydrogen at dislocations provides sufficient hydrogen to build up a required critical hydrogen concentration at potential flaws for crack nucleation and to activate hydrogen enhanced decohesion mechanism. Further, it was found that δ phase precipitation exacerbates the hydrogen embrittlement sensitivity. For the first time, evidence for hydrogen transport by dislocations in a Ni-based alloy is observed by the hydrogen visualization technique.

UR - http://www.scopus.com/inward/record.url?scp=85132695740&partnerID=8YFLogxK

U2 - 10.1016/j.msea.2022.143428

DO - 10.1016/j.msea.2022.143428

M3 - Article

VL - 848.2022

JO - Materials Science and Engineering A

JF - Materials Science and Engineering A

SN - 0921-5093

IS - 19 July

M1 - 143428

ER -