Journal of Materials Research and Technology (Nov 2024)

Rate-dependent serration behavior of twinning-induced plasticity steel at ultra-low temperature

  • Taeho Lee,
  • Chetan Singh,
  • You Sub Kim,
  • Dong-Hyun Lee,
  • Jun Hyun Han,
  • Jun-Yun Kang,
  • Soo Yeol Lee

Journal volume & issue
Vol. 33
pp. 2580 – 2592

Abstract

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This study investigates the strain rate-dependent deformation behavior of cost-effective twinning-induced plasticity (TWIP) steel, Fe–26Mn-0.4C, at 15 K and reveals intriguing insights into its mechanical properties. The serration type changes from type A to type C with decreasing strain rate, resulting in a quasi-cleavage fracture at the crack initiation site. Microstructural analysis unveils a correlation between strain rate and the evolution of bundle twins, nano-twins, and ε-martensites. These denser networks of deformation twins (DTs) and ε-martensites contribute to impacting the mechanical properties. The mechanism behind the formation of serrations involves a rate-dependent thermal instability effect and the intricate interactions between dislocations and dislocations/Mn–C couples. The distinct findings enhance our understanding of the complex deformation behavior of high-Mn steel at cryogenic temperatures and provide valuable insights into the broader field of high-Mn steel applications in dynamic environments.

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