Inverse temperature dependence of toughness in an ultrafine grain-structure steel

Yuuji Kimura, Tadanobu Inoue, Fuxing Yin, Kaneaki Tsuzaki

Research output: Contribution to journalArticlepeer-review

323 Citations (Scopus)


Materials are typically ductile at higher temperatures and become brittle at lower temperatures. In contrast to the typical ductile-to-brittle transition behavior of body-centered cubic (bcc) steels, we observed an inverse temperature dependence of toughness in an ultrahigh-strength bcc steel with an ultrafine elongated ferrite grain structure that was processed by a thermomechanical treatment without the addition of a large amount of an alloying element. The enhanced toughness is attributed to a delamination that was a result of crack branching on the aligned {100} cleavage planes in the bundles of the ultrafine elongated ferrite grains strengthened by nanometer-sized carbides. In the temperature range from 60° to -60°C, the yield strength was greater, leading to the enhancement of the toughness.

Original languageEnglish
Pages (from-to)1057-1060
Number of pages4
Issue number5879
Publication statusPublished - May 23 2008
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General


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