Hydrogen-enhanced deformation in pearlite
Journal
Acta Materialia
Journal Volume
281
Start Page
120327
ISSN
1359-6454
Date Issued
2024-12-01
Author(s)
Ranming Niu
Hanyu Li
Pang-Yu Liu
Patrick Burr
Yi Feng
Chao Huang
Yi-Hsuan Sun
Mingtu Ma
Aimin Guo
Hongzhou Lu
Yi-Sheng Chen
Julie M. Cairney
DOI
10.1016/j.actamat.2024.120327
Abstract
Hydrogen-induced degradation of pipeline steels is a serious safety challenge for the transport of hydrogen. Steel pipes contain a large proportion of the pearlite phase, which consists of lamellar cementite in ferrite. How hydrogen interacts with pearlite and degrades the mechanical properties remains unclear. Here we have studied the deformation behavior of pearlite in the presence of hydrogen. In-situ micromechanical results revealed that H softens the pearlite. Uncharged samples deform by slip at the ferrite–cementite interface, while deformation in H-charged pearlitic samples occurs predominantly via slip within the ferrite phase, with some shearing of the cementite. Cryo atom probe tomography confirms that hydrogen is associated with defects in the ferrite, away from the interface, and is trapped within the cementite, which is thought to be the result of a high concentration of C vacancies. Hydrogen is not observed at the ferrite–cementite interface. First principal simulations show that the expected influence of lattice strain and cementite vacancies on hydrogen trapping is consistent with the experimental results. The softening is attributed to a reduction in the energy required for dislocation motion in both the ferrite and the cementite.
Subjects
Cryogenic atom probe tomography
Hydrogen embrittlement
Micromechanics
Pearlite
Plasticity
SDGs
Publisher
Elsevier BV
Type
journal article