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Chapter
Microstructural Crack Tip Plasticity Controlling Small Fatigue Crack Growth
In this chapter, we present a metallurgical–mechanical mechanism-based strategy for the design of fatigue-resistant metals. Specifically, we elucidate the importance of the metallurgical microstructure in a me...
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Chapter
Potential Effects of Short-Range Order on Hydrogen Embrittlement of Stable Austenitic Steels—A Review
Here, we present a review of the hydrogen embrittlement behavior of face-centered cubic (FCC) alloys with short-range order (SRO) of solute atoms. In this paper, three types of FCC alloys are introduced: Fe–Mn...
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Article
Effects of Mn Content and Grain Size on Hydrogen Embrittlement Susceptibility of Face-Centered Cubic High-Entropy Alloys
The effects of Mn content and grain size on the hydrogen embrittlement resistance of face-centered cubic (FCC) CrCoFeMnNi high-entropy alloys were examined using tensile testing at an initial strain rate of 10−4 ...
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Article
Hydrogen Enhances Shape Memory Effect of a Ferrous Face-Centered Cubic Alloy
This paper marks the first report on the fact that interstitial hydrogen improves the shape recovery property of an Fe-based face-centered cubic alloy, regardless of pre-strain level. The maximum shape recover...
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Article
Open AccessIn-Situ Electron Channeling Contrast Imaging under Tensile Loading: Residual Stress, Dislocation Motion, and Slip Line Formation
Elastoplastic phenomena, such as plastic deformation and failure, are multi-scale, deformation-path-dependent, and mechanical-field-sensitive problems associated with metals. Accordingly, visualization of the ...
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Article
Effect of Hydrogen on the Substructure of Lenticular Martensite in Fe-31Ni Alloy
This study investigated the effect of hydrogen on the substructure of martensite in Fe-31Ni alloy. In both the hydrogen-charged and uncharged specimens, typical lenticular martensite plates formed after subzer...
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Article
Lowering Strain Rate Simultaneously Enhances Carbon- and Hydrogen-Induced Mechanical Degradation in an Fe-33Mn-1.1C Steel
We investigated the strain rate dependency of the hydrogen-induced mechanical degradation of Fe-33Mn-1.1C steel at 303 K within the strain rate range of 10−2 to 10−5 s−1. In the presence of hydrogen, lowering the...
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Article
Open AccessAn unconventional hydrogen effect that suppresses thermal formation of the hcp phase in fcc steels
Iron and steels are extensively used as structural materials, and have three primary phase structures: Body-centered cubic (bcc), face-centered cubic (fcc), and hexagonal closed-packed (hcp). Controlling phase...
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Article
Microstructural damage evolution and arrest in binary Fe–high-Mn alloys with different deformation temperatures
We investigated the damage evolution behaviors of binary Fe–28–40Mn alloys (mass%) from 93 to 393 K by tensile testing. The underlying mechanisms of the microstructure-dependent damage evolution behavior were ...
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Article
Effects of martensitic transformability and dynamic strain age hardenability on plasticity in metastable austenitic steels containing carbon
We investigated the effects of solute carbon concentration on the mechanical properties of Fe–19Cr–8Ni–0.05C and Fe–19Cr–8Ni–0.14C metastable austenitic steels. These steels showed an FCC(γ) → HCP(ε) → BCC(α′...
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Article
Advanced Thermomechanical Processing for a High-Mn Austenitic Steel
The microstructures and mechanical properties of a warm-forged and annealed Fe-18Mn-0.6C-1.5Al TWIP steel were studied. The high dislocation density was evolved by warm forging and the ultrafine grains were de...
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Article
Hydrogen Embrittlement Susceptibility of Fe-Mn Binary Alloys with High Mn Content: Effects of Stable and Metastable ε-Martensite, and Mn Concentration
To obtain a basic understanding of hydrogen embrittlement associated with ε-martensite, we investigated the tensile behavior of binary Fe-Mn alloys with high Mn content under cathodic hydrogen charging. We use...
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Chapter and Conference Paper
Quantitative Analysis of Twinning-Induced Plasticity (TWIP) in Beta-Titanium Alloy
Work hardening behavior of Ti-15Mo alloy (mass %) was examined through quantitative evaluation of the {332}<113> twinning structural evolution at various plastic strain levels by optical microscope (OM) observ...
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Chapter and Conference Paper
Low-cycle fatigue properties of the Fe-30Mn-(6-x)Si-xAl TRIP/TWIP alloys
Low-cycle fatigue (LCF) properties of the Fe-30Mn-(6-x)Si-xAl alloys ascribed to TRIP/TWIP high-Mn austenitic alloys were examined in relation with tensile properties. It was found that fatigue resistance of t...
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Article
Microstructure Evolution Associated with a Superior Low-Cycle Fatigue Resistance of the Fe-30Mn-4Si-2Al Alloy
The microstructure evolution responsible for the superior low-cycle fatigue (LCF) resistance (N f > 8000 cycles at a total strain range of 2 pct) was studied in the Fe-30Mn-4Si-2Al alloy s...
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Article
Effect of Initial Microstructure on Impact Toughness of 1200 MPa-Class High Strength Steel with Ultrafine Elongated Grain Structure
A medium-carbon low-alloy steel was prepared with initial structures of either martensite or bainite. For both initial structures, warm caliber-rolling was conducted at 773 K (500 °C) to obtain ultrafine elong...
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Article
Studies of Evaluation of Hydrogen Embrittlement Property of High-Strength Steels with Consideration of the Effect of Atmospheric Corrosion
Hydrogen embrittlement of high-strength steels was investigated by using slow strain rate test (SSRT) of circumferentially notched round bar specimens after hydrogen precharging. On top of that, cyclic corrosi...
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Article
Ultrafine-Grain Structure Formation in an Al-Mg-Sc Alloy During Warm ECAP
Microstructural evolution taking place during equal-channel angular pressing was studied in a commercial Al-6Mg-0.3Sc alloy at 523 K (250 °C) (~0.5T m). The structural changes are mainly associate...
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Article
Premature Fracture Mechanism in an Fe-Mn-C Austenitic Steel
We investigated the cause for poor ductility in austenitic Fe-Mn-C steels under a specific condition. Tensile tests were performed on an Fe-17Mn-0.3C steel at 273 K, 294 K, 323 K, 373 K, 423 K, 473 K, and 523 ...
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Article
Enhancement of Upper Shelf Energy through Delamination Fracture in 0.05 pct P Doped High-Strength Steel
An ultrafine elongated grain (UFEG) structure with strong 〈110〉//rolling direction (RD) fiber deformation texture was produced by warm-caliber rolling at 773 K (500 °C) and final tempering at 823 K (550 °C), n...
