Tensile behavior of ferrite-martensite dual phase steels with nano-precipitation of vanadium carbides

Naoya Kamikawa, Masahiro Hirohashi, Yu Sato, Elango Chandiran, Goro Miyamoto, Tadashi Furuhara

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


This paper reports the effect of nano-precipitation strengthening of ferrite on the tensile behavior of ferrite-martensite dual phase (DP) steels. Samples of ferrite-martensite DP steel containing a dispersion of nano-sized vanadium carbides (VCs) in the ferrite phase were produced by interphase precipitation and quenching of a V-added low carbon steel, and the mechanical properties are compared with those of conventional ferrite-martensite DP samples without VC particles. Both the yield stress and the ultimate tensile strength are significantly increased by nano-VC precipitates. For ferrite volume fractions of 20-50% a dispersion of VCs results in only a small change in the elongation, whereas for ferrite volume fractions of above 50% both uniform and post-uniform elongations are decreased by a VC dispersion. It is suggested that dispersion of nano-precipitates in ferrite is an effective approach to simultaneously improve the strength and the strength-ductility balance of DP steels. Digital image correlation (DIC) analysis demonstrates that the ferrite phase is more deformed than the martensite phase in both VC-free and VC-dispersed DP samples, but that such strain partitioning is less pronounced in the VC dispersion-hardened samples. It is found that the stress-strain relationship of DP samples can reasonably be explained based on a law of mixtures using partitioned strain and stress values as estimated from the DIC analysis.

Original languageEnglish
Pages (from-to)1781-1790
Number of pages10
JournalIsij International
Issue number8
Publication statusPublished - 2015


  • Digital image correlation (DIC)
  • Dual phase (DP) steel
  • Interphase precipitation
  • Mechanical property
  • Strain and stress partitioning
  • Vanadium carbides (VC)

ASJC Scopus subject areas

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


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