TY - JOUR
T1 - Delamination toughening assisted by phosphorus in medium-carbon low-alloy steels with ultrafine elongated grain structures
AU - Min, Xiaohua
AU - Kimura, Yuuji
AU - Kimura, Takashi
AU - Tsuzaki, Kaneaki
N1 - Funding Information:
The authors thank Mr. Kuroda and Mr. Taniuchi for the caliber-rolling processing of the materials, and Ms. Hirota and Mr. Nishio for their assistance with the SEM and EPMA observations. This study was financially supported by Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST) .
Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - The effect of phosphorus (P) on delamination toughening was examined for 0.4%C-1%Cr-0.7%Mn-0.2%Mo steels (mass%) comprised of ultrafine elongated grain (UFEG) structures with strong <110>//rolling direction (RD) fiber textures. The UFEG structures evolved through the plastic deformation of tempered martensitic structures by multi-pass caliber rolling at a temperature of 773. K (warm tempforming, WTF). The addition of P, up to 0.093% (mass%), had little influence on the evolution of the UFEG structure and the strength of the steels. Although the tensile ductility and upper-shelf energy showed a slight tendency to decrease as the P concentration increased from 0.001% to 0.093%, the delamination perpendicular to the notch orientation of the impact specimens was pronounced over a wider temperature range. As a result of delamination, the 0.093% P-doped steel exhibited a significant inverse temperature dependence of toughness at temperatures from 250. K to 350. K. The delamination toughening was dominated by the UFEG structure, and further assisted by the phosphorus segregation. It was considered that the formation of distinct P segregation bands, which presented a structure consisting of brittle and ductile layers, may be especially effective in accelerating delamination and improving toughness in the P-doped steel with an UFEG structure.
AB - The effect of phosphorus (P) on delamination toughening was examined for 0.4%C-1%Cr-0.7%Mn-0.2%Mo steels (mass%) comprised of ultrafine elongated grain (UFEG) structures with strong <110>//rolling direction (RD) fiber textures. The UFEG structures evolved through the plastic deformation of tempered martensitic structures by multi-pass caliber rolling at a temperature of 773. K (warm tempforming, WTF). The addition of P, up to 0.093% (mass%), had little influence on the evolution of the UFEG structure and the strength of the steels. Although the tensile ductility and upper-shelf energy showed a slight tendency to decrease as the P concentration increased from 0.001% to 0.093%, the delamination perpendicular to the notch orientation of the impact specimens was pronounced over a wider temperature range. As a result of delamination, the 0.093% P-doped steel exhibited a significant inverse temperature dependence of toughness at temperatures from 250. K to 350. K. The delamination toughening was dominated by the UFEG structure, and further assisted by the phosphorus segregation. It was considered that the formation of distinct P segregation bands, which presented a structure consisting of brittle and ductile layers, may be especially effective in accelerating delamination and improving toughness in the P-doped steel with an UFEG structure.
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U2 - 10.1016/j.msea.2015.09.102
DO - 10.1016/j.msea.2015.09.102
M3 - Article
AN - SCOPUS:84943613554
VL - 649
SP - 135
EP - 145
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
SN - 0921-5093
ER -