Effects of Ti alloying on resistance to hydrogen embrittlement in (Nb+Mo)-alloyed ultra-high-strength hot-stamping steels

Jisung Yoo; Min Chul Jo; Min Cheol Jo; Seongwoo Kim; Jinkeun Oh; Jian Bian; Seok Su Sohn; Sunghak Lee

doi:10.1016/j.msea.2020.139763

Effects of Ti alloying on resistance to hydrogen embrittlement in (Nb+Mo)-alloyed ultra-high-strength hot-stamping steels

Jisung Yoo, Min Chul Jo, Min Cheol Jo, Seongwoo Kim, Jinkeun Oh, Jian Bian, Seok Su Sohn, Sunghak Lee

Research output: Contribution to journal › Article › peer-review

50 Citations (Scopus)

Abstract

A boron-containing 1.8–2.0-GPa-grade hot-stamping steel, which has been attracting great attentions as reinforcing automotive parts, often leads to the deteriorated resistance to hydrogen embrittlement due to its high strength level. The micro-alloying elements such as Nb and Mo have been known to improve the resistance to hydrogen embrittlement by refining grains and providing interfaces of precipitates. Ti is also utilized for the mentioned purposes; however, the effect of Ti on hydrogen embrittlement, particularly in (Nb + Mo) multi-alloyed system, has not been revealed clearly yet. In this study, therefore, the alloying effects of Ti on resistance to hydrogen embrittlement were investigated via controlling Ti content and conducting slow-strain-rate tensile (SSRT) tests and thermal desorption analyses (TDA) after the hydrogen charging. The complex addition of Nb, Mo, and Ti promotes the formation of nanoscale (Nb,Ti)C and (Nb,Mo,Ti)C complex precipitates along with coarse Ti(C,N) particles. The increased Ti content to 0.03 wt% increases the volume fraction of nanoscale precipitates, which effectively refines the prior austenite grain size and interfacial incoherency, thereby providing stable hydrogen trapping sites with the higher activation energy for hydrogen desorption. Although the increased Ti also promotes the formation of brittle coarse Ti(C,N) particles, this negative effect of the particles can be minimized or prevented by the decrease in particle size due to the interaction with Nb and Mo.

Original language	English
Article number	139763
Journal	Materials Science and Engineering A
Volume	791
DOIs	https://doi.org/10.1016/j.msea.2020.139763
Publication status	Published - 2020 Jul 22

Bibliographical note

Funding Information:
This work was supported by CBMM , POSCO Technical Research Laboratories , the Korea University Grant for first corresponding author, and Brain Korea 21 PLUS Project for Center for Creative Industrial Materials.

Funding Information:
This work was supported by CBMM, POSCO Technical Research Laboratories, the Korea University Grant for first corresponding author, and Brain Korea 21 PLUS Project for Center for Creative Industrial Materials.

Publisher Copyright:
© 2020 Elsevier B.V.

Keywords

32MnB5 steel
Complex carbide
Grain refinement
Hot-stamping steel
Resistance to hydrogen embrittlement

ASJC Scopus subject areas

General Materials Science
Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

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@article{704be8c342904656946b2babe5790799,

title = "Effects of Ti alloying on resistance to hydrogen embrittlement in (Nb+Mo)-alloyed ultra-high-strength hot-stamping steels",

abstract = "A boron-containing 1.8–2.0-GPa-grade hot-stamping steel, which has been attracting great attentions as reinforcing automotive parts, often leads to the deteriorated resistance to hydrogen embrittlement due to its high strength level. The micro-alloying elements such as Nb and Mo have been known to improve the resistance to hydrogen embrittlement by refining grains and providing interfaces of precipitates. Ti is also utilized for the mentioned purposes; however, the effect of Ti on hydrogen embrittlement, particularly in (Nb + Mo) multi-alloyed system, has not been revealed clearly yet. In this study, therefore, the alloying effects of Ti on resistance to hydrogen embrittlement were investigated via controlling Ti content and conducting slow-strain-rate tensile (SSRT) tests and thermal desorption analyses (TDA) after the hydrogen charging. The complex addition of Nb, Mo, and Ti promotes the formation of nanoscale (Nb,Ti)C and (Nb,Mo,Ti)C complex precipitates along with coarse Ti(C,N) particles. The increased Ti content to 0.03 wt% increases the volume fraction of nanoscale precipitates, which effectively refines the prior austenite grain size and interfacial incoherency, thereby providing stable hydrogen trapping sites with the higher activation energy for hydrogen desorption. Although the increased Ti also promotes the formation of brittle coarse Ti(C,N) particles, this negative effect of the particles can be minimized or prevented by the decrease in particle size due to the interaction with Nb and Mo.",

keywords = "32MnB5 steel, Complex carbide, Grain refinement, Hot-stamping steel, Resistance to hydrogen embrittlement",

author = "Jisung Yoo and Jo, {Min Chul} and Jo, {Min Cheol} and Seongwoo Kim and Jinkeun Oh and Jian Bian and Sohn, {Seok Su} and Sunghak Lee",

note = "Funding Information: This work was supported by CBMM , POSCO Technical Research Laboratories , the Korea University Grant for first corresponding author, and Brain Korea 21 PLUS Project for Center for Creative Industrial Materials. Funding Information: This work was supported by CBMM, POSCO Technical Research Laboratories, the Korea University Grant for first corresponding author, and Brain Korea 21 PLUS Project for Center for Creative Industrial Materials. Publisher Copyright: {\textcopyright} 2020 Elsevier B.V.",

year = "2020",

month = jul,

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doi = "10.1016/j.msea.2020.139763",

language = "English",

volume = "791",

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T1 - Effects of Ti alloying on resistance to hydrogen embrittlement in (Nb+Mo)-alloyed ultra-high-strength hot-stamping steels

AU - Yoo, Jisung

AU - Jo, Min Chul

AU - Jo, Min Cheol

AU - Kim, Seongwoo

AU - Oh, Jinkeun

AU - Bian, Jian

AU - Sohn, Seok Su

AU - Lee, Sunghak

N1 - Funding Information: This work was supported by CBMM , POSCO Technical Research Laboratories , the Korea University Grant for first corresponding author, and Brain Korea 21 PLUS Project for Center for Creative Industrial Materials. Funding Information: This work was supported by CBMM, POSCO Technical Research Laboratories, the Korea University Grant for first corresponding author, and Brain Korea 21 PLUS Project for Center for Creative Industrial Materials. Publisher Copyright: © 2020 Elsevier B.V.

PY - 2020/7/22

Y1 - 2020/7/22

N2 - A boron-containing 1.8–2.0-GPa-grade hot-stamping steel, which has been attracting great attentions as reinforcing automotive parts, often leads to the deteriorated resistance to hydrogen embrittlement due to its high strength level. The micro-alloying elements such as Nb and Mo have been known to improve the resistance to hydrogen embrittlement by refining grains and providing interfaces of precipitates. Ti is also utilized for the mentioned purposes; however, the effect of Ti on hydrogen embrittlement, particularly in (Nb + Mo) multi-alloyed system, has not been revealed clearly yet. In this study, therefore, the alloying effects of Ti on resistance to hydrogen embrittlement were investigated via controlling Ti content and conducting slow-strain-rate tensile (SSRT) tests and thermal desorption analyses (TDA) after the hydrogen charging. The complex addition of Nb, Mo, and Ti promotes the formation of nanoscale (Nb,Ti)C and (Nb,Mo,Ti)C complex precipitates along with coarse Ti(C,N) particles. The increased Ti content to 0.03 wt% increases the volume fraction of nanoscale precipitates, which effectively refines the prior austenite grain size and interfacial incoherency, thereby providing stable hydrogen trapping sites with the higher activation energy for hydrogen desorption. Although the increased Ti also promotes the formation of brittle coarse Ti(C,N) particles, this negative effect of the particles can be minimized or prevented by the decrease in particle size due to the interaction with Nb and Mo.

AB - A boron-containing 1.8–2.0-GPa-grade hot-stamping steel, which has been attracting great attentions as reinforcing automotive parts, often leads to the deteriorated resistance to hydrogen embrittlement due to its high strength level. The micro-alloying elements such as Nb and Mo have been known to improve the resistance to hydrogen embrittlement by refining grains and providing interfaces of precipitates. Ti is also utilized for the mentioned purposes; however, the effect of Ti on hydrogen embrittlement, particularly in (Nb + Mo) multi-alloyed system, has not been revealed clearly yet. In this study, therefore, the alloying effects of Ti on resistance to hydrogen embrittlement were investigated via controlling Ti content and conducting slow-strain-rate tensile (SSRT) tests and thermal desorption analyses (TDA) after the hydrogen charging. The complex addition of Nb, Mo, and Ti promotes the formation of nanoscale (Nb,Ti)C and (Nb,Mo,Ti)C complex precipitates along with coarse Ti(C,N) particles. The increased Ti content to 0.03 wt% increases the volume fraction of nanoscale precipitates, which effectively refines the prior austenite grain size and interfacial incoherency, thereby providing stable hydrogen trapping sites with the higher activation energy for hydrogen desorption. Although the increased Ti also promotes the formation of brittle coarse Ti(C,N) particles, this negative effect of the particles can be minimized or prevented by the decrease in particle size due to the interaction with Nb and Mo.

KW - 32MnB5 steel

KW - Complex carbide

KW - Grain refinement

KW - Hot-stamping steel

KW - Resistance to hydrogen embrittlement

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DO - 10.1016/j.msea.2020.139763

M3 - Article

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SN - 0921-5093

VL - 791

JO - Materials Science and Engineering A

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ER -

Effects of Ti alloying on resistance to hydrogen embrittlement in (Nb+Mo)-alloyed ultra-high-strength hot-stamping steels

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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