Understanding of adiabatic shear band evolution during high-strain-rate deformation in high-strength armor steel

Min Cheol Jo, Selim Kim, Dae Woong Kim, Hyung Keun Park, Sung Suk Hong, Hong Kyu Kim, Hyoung Seop Kim, Seok Su Sohn, Sunghak Lee

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

The microstructural evolution and formation mechanism of adiabatic shear band (ASB) in a high-strength armor steel were investigated using a laboratory-scale split Hopkinson pressure bar, and the results were correlated with the actual ballistic impact behavior. The interrupted dynamic compressive test results reveal that a deformed ASB (dASB) starts to form right after the stress collapse and it develops into a transformed ASB (tASB). In the ballistic impact, wide tASBs form mostly at the perforated surface, and narrower tASBs are branched from the tASB. Very fine equiaxed grains of ∼190 nm in the tASB developed during the dynamic compression indicates that the dynamic recrystallization occurs even in 86.5 μs, and then the grains grow up to 260 nm in 9.5 μs. Rotational dynamic recrystallization mechanism and grain-growth rate model were proposed based on the calculation of temperature rise from a thermo-elasto-plastic finite element method, which provide a reasonable explanation for the formation and growth of fine equiaxed grains during both the dynamic compression and ballistic impact. A linkage of equiaxed subgrains and elongated parent subgrains demonstrates that the equiaxed subgrains did not evolve from nucleation and growth processes but from the sub-boundary rotation. Based on the underlying formation mechanisms and kinetics of ASBs, this study would suggest a reliable method to interpret the ASB formation and associated fracture mechanism during the ballistic impact.

Original languageEnglish
Article number155540
JournalJournal of Alloys and Compounds
Volume845
DOIs
Publication statusPublished - 2020 Dec 10

Keywords

  • Adiabatic shear band
  • Ballistic impact
  • Dynamic recrystallization
  • High-strength armor steel
  • Split hopkinson pressure bar

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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