Inverse Temperature Dependence of Toughness in an Ultrafine Grain-Structure Steel
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- Yuuji Kimura
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
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- Tadanobu Inoue
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
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- Fuxing Yin
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
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- Kaneaki Tsuzaki
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
書誌事項
- 公開日
- 2008-05-23
- DOI
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- 10.1126/science.1156084
- 公開者
- American Association for the Advancement of Science (AAAS)
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説明
<jats:p>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.</jats:p>
収録刊行物
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- Science
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Science 320 (5879), 1057-1060, 2008-05-23
American Association for the Advancement of Science (AAAS)
