Effects of Cu addition on resistance to hydrogen embrittlement in 1 GPa-grade duplex lightweight steels

Yoo, Jisung; Jo, Min Chul; Kim, Dae Woong; Song, Hyejin; Koo, Minseo; Sohn, Seok Su; Lee, Sunghak

doi:10.1016/j.actamat.2020.06.051

Cited by 44 publications

(9 citation statements)

References 83 publications

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“…However, the fracture strength of 1500HT after hydrogen pre-charging is lower than 1500LT. In literature, the elongation loss is more commonly used to evaluate hydrogen embrittlement of dog-bone samples of ductile steels, rather than strength loss [14,18,[37][38][39]. In addition to dog-bone samples, hydrogen embrittlement of notched samples is studied.…”

Section: Resultsmentioning

confidence: 99%

Improving Hydrogen Embrittlement Resistance of Hot-Stamped 1500 MPa Steel Parts That Have Undergone a Q&P Treatment by the Design of Retained Austenite and Martensite Matrix

Wang

Huang

2020

Metals

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Hydrogen embrittlement is one of the largest obstacles against the commercialisation of ultra-high strength quenching and partitioning (Q&P) steels with ultimate tensile strength over 1500 MPa, including the hot stamped steel parts that have undergone a Q&P treatment. In this work, the influence of partitioning temperature on hydrogen embrittlement of ultra-high strength Q&P steels is studied by pre-charged tensile tests with both dog-bone and notched samples. It is found that hydrogen embrittlement resistance is enhanced by the higher partitioning temperature. Then, the hydrogen embrittlement mechanism is analysed in terms of hydrogen, retained austenite, and martensite matrix. Thermal desorption analysis (TDA) shows that the hydrogen trapping properties are similar in the Q&P steels, which cannot explain the enhancement of hydrogen embrittlement resistance. On the contrary, it is found that the relatively low retained austenite stability after the higher temperature partitioning ensures more sufficient TRIP effect before hydrogen-induced fracture. Additionally, dislocation recovery and solute carbon depletion at the higher partitioning temperature can reduce the flow stress of the martensite matrix, improving its intrinsic toughness and reducing its hydrogen sensitivity, both of which result in the higher hydrogen embrittlement resistance.

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Section: Resultsmentioning

confidence: 99%

Improving Hydrogen Embrittlement Resistance of Hot-Stamped 1500 MPa Steel Parts That Have Undergone a Q&P Treatment by the Design of Retained Austenite and Martensite Matrix

Wang

Huang

2020

Metals

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“…A full transition in plasticity mechanism from TRIP to perfect dislocation glide and shear banding is noted in a duplex microstructure of relatively high-alloyed steels. For example, in the study by Yoo et al [58], the Fe-0.8C-15Mn-7Al alloy for which plastic deformation in austenite is governed by dislocation glide exhibited generally high resistance to H-delayed fracture, comparable to or better than those of fully austenitic TWIP steels. One challenge with the design of an H-resistant duplex or multiphase steel exists in quantifying or predicting the mechanical stability of the austenite in a multiphase microstructure, as the chemical composition of the austenite significantly varies depending on the processing history, phase fraction, and solute partitioning behavior.…”

Section: Alloying and Microstructural Engineering Strategies To Improve H-resistancementioning

confidence: 99%

“…Yoo et al [58] reported that additions of 1-3 wt pct Cu improved the H-resistance of a duplex (ferrite austenite) lightweight steel (Fe-0.8C-15Mn-7Al, in wt pct). In their study, the Cu additions promoted the formation of Cu-rich B2 phase primary along the austenite grain boundaries, which was interpreted to trap H atoms and slow H transport during deformation.…”

Section: Other Alloying Elements and Precipitatesmentioning

confidence: 99%

“…Cu as a solute is also known to increase SFE of austenite; for example, in a study by Choi et al [59], the addition of 1-2 wt pct Cu resulted in a transition from a TRIP to a TWIP deformation mechanism in a high Mn austenitic-based steel. Yoo et al [58] also emphasized the role of Cu in increasing the SFE of austenite and promoting wavy glide of dislocations as low SFE and planar slip are generally thought to be detrimental to H-resistance in austenite. It should be pointed out that the alloy investigated in the study by Yoo et al [58] was relatively highly alloyed, which resulted in a high SFE of the austenite that limited αʹ-or ε-martensitic transformation, in the steel microstructure designed to have a mixture of ferrite and austenite.…”

Section: Other Alloying Elements and Precipitatesmentioning

confidence: 99%

“…Yoo et al [58] also emphasized the role of Cu in increasing the SFE of austenite and promoting wavy glide of dislocations as low SFE and planar slip are generally thought to be detrimental to H-resistance in austenite. It should be pointed out that the alloy investigated in the study by Yoo et al [58] was relatively highly alloyed, which resulted in a high SFE of the austenite that limited αʹ-or ε-martensitic transformation, in the steel microstructure designed to have a mixture of ferrite and austenite. Finally, Cu additions (1-2 wt pct) have been reported to enhance the HE resistance of a fully austenitic, high Mn TWIP steel (Fe-17Mn-0.8C, in wt pct) [60].…”

Section: Other Alloying Elements and Precipitatesmentioning

confidence: 99%

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Hydrogen Embrittlement of Medium Mn Steels

Cho

Kong

Speer

et al. 2021

Metals

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Recent research efforts to develop advanced–/ultrahigh–strength medium-Mn steels have led to the development of a variety of alloying concepts, thermo-mechanical processing routes, and microstructural variants for these steel grades. However, certain grades of advanced–/ultrahigh–strength steels (A/UHSS) are known to be highly susceptible to hydrogen embrittlement, due to their high strength levels. Hydrogen embrittlement characteristics of medium–Mn steels are less understood compared to other classes of A/UHSS, such as high Mn twinning–induced plasticity steel, because of the relatively short history of the development of this steel class and the complex nature of multiphase, fine-grained microstructures that are present in medium–Mn steels. The motivation of this paper is to review the current understanding of the hydrogen embrittlement characteristics of medium or intermediate Mn (4 to 15 wt pct) multiphase steels and to address various alloying and processing strategies that are available to enhance the hydrogen-resistance of these steel grades.

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Hydrogen Embrittlement and Microstructure Characterization of 1500 MPa Martensitic Steel

Tang

et al. 2022

steel research int.

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The application of ultrahigh‐strength martensitic steel in automotive key parts can achieve automotive lightweight. However, the hydrogen embrittlement sensitivity of ultrahigh‐strength martensitic steel is widely concerned by the industry. This article compares the microstructure and the hydrogen brittleness resistance of two 1500 MPa martensitic steels. The grain boundary, the grain size, the martensitic lath, and the precipitate phase in martensitic steel are analyzed by electron backscatter diffraction and transmission electron microscope. The hydrogen desorption curves of the two steels are measured by thermal desorption analysis, and the phenomenon of hydrogen trapping in the materials is analyzed. A U‐bend test is used to compare the hydrogen embrittlement of these two samples. The results demonstrate that the thickness of the martensitic lath and the dislocation are directly related to the diffuse hydrogen concentration in the material. In addition, the Cu‐rich nanoparticles show a better hydrogen trapping effect, which is beneficial in improving the hydrogen embrittlement resistance of the material.

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Effects of Cu addition on resistance to hydrogen embrittlement in 1 GPa-grade duplex lightweight steels

Cited by 44 publications

References 83 publications

Improving Hydrogen Embrittlement Resistance of Hot-Stamped 1500 MPa Steel Parts That Have Undergone a Q&P Treatment by the Design of Retained Austenite and Martensite Matrix

Improving Hydrogen Embrittlement Resistance of Hot-Stamped 1500 MPa Steel Parts That Have Undergone a Q&P Treatment by the Design of Retained Austenite and Martensite Matrix

Hydrogen Embrittlement of Medium Mn Steels

Hydrogen Embrittlement and Microstructure Characterization of 1500 MPa Martensitic Steel

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