Stress-state dependence of dynamic strain aging: Thermal hardening and blue brittleness

Wen qi Liu, Jun he Lian*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

1 Citation (Scopus)
10 Downloads (Pure)

Abstract

This study aims to discover the stress-state dependence of the dynamic strain aging (DSA) effect on the deformation and fracture behavior of high-strength dual-phase (DP) steel at different deformation temperatures (25–400°C) and reveal the damage mechanisms under these various configurations. To achieve different stress states, predesigned specimens with different geometric features were used. Scanning electron microscopy was applied to analyze the fracture modes (e.g., dimple or shear mode) and underlying damage mechanism of the investigated material. DSA is present in this DP steel, showing the Portevin-Le Chatelier (PLC) effect with serrated flow behavior, thermal hardening, and blue brittleness phenomena. Results show that the stress state contributes distinctly to the DSA effect in terms of the magnitude of thermal hardening and the pattern of blue brittleness. Either low stress triaxiality or Lode angle parameter promotes DSA-induced blue brittleness. Accordingly, the damage mechanisms also show dependence on the stress states in conjunction with the DSA effect.

Original languageEnglish
Pages (from-to)854-866
Number of pages13
JournalInternational Journal of Minerals, Metallurgy and Materials
Volume28
Issue number5
DOIs
Publication statusPublished - 6 May 2021
MoE publication typeA1 Journal article-refereed

Keywords

  • damage mechanism
  • dimple fracture
  • dual-phase steel
  • dynamic strain aging effect
  • Portevin-Le Chatelier effect
  • shear fracture

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