Effects of lamellar structure on tensile properties and resistance to hydrogen embrittlement of pearlitic steel

Sang Hyun Yu, Sang Min Lee, Sukjin Lee, Jae Hoon Nam, Jae Seung Lee, Chul Min Bae, Young Kook Lee

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26 Citations (Scopus)


The hydrogen embrittlement (HE) and H trapping sites of pearlitic steel specimens with various lamellar spacings (λ) were evaluated through slow strain rate tensile testing and thermal desorption analysis. When λ decreases, both tensile strength and resistance to HE were unusually improved. This is because tearing, which is the initiation of H cracking, was delayed in the specimen with fine λ and short cementite (θ) platelets. Undeformed H-charged specimens showed a peak (peak 1), which is separable into two sub-peaks (peak 1-1 and peak 1–2) in their H desorption rate curves, regardless of λ. Peak 1-1 and peak 1–2 were generated by H atoms detrapped from FP/θ interfaces and from dislocations inside FP, respectively. The Ea values of H desorption for peak 1-1 and peak 1–2 were 23.2 kJ/mol, and 26.1 kJ/mol, respectively. Meanwhile, deformed H-charged specimens exhibited the second peak (peak 2) with peak temperature (TP) of ∼600 K, as well as peak 1 with TP of ∼375 K. When tensile strain increased, peak 2 increased at the expense of peak 1. Primary H trapping sites for peak 2 are strained FP/θ interfaces with interfacial dislocations.

Original languageEnglish
Pages (from-to)92-101
Number of pages10
JournalActa Materialia
Publication statusPublished - 2019 Jun 15

Bibliographical note

Funding Information:
The authors gratefully acknowledge the support of the POSCO Technical Research Laboratories, Pohang, Republic of Korea.

Publisher Copyright:
© 2019 Acta Materialia Inc.

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys


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