Evolution of Fracture Mode in Nano-twinned Fe-1.1C-12.5Mn Steel

Khedr, Mahmoud; Li, Wei; Min, Na; Li, Yu; Jin, Xuejun

doi:10.1007/s11837-019-03329-7

Cited by 10 publications

(7 citation statements)

References 43 publications

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“…It is noteworthy that the annealing twins disappeared in the FB, while they remained noticeable in the TZ and HAZ. The twin plates were reoriented in a similar manner as the parent matrix when the temperature reached 1000 °C (known as the de-twinning phenomenon) [ 37 , 38 ]. Therefore, the disappearance of the twin plates in the FB confirms that the temperature there exceeded 1000 °C, while the existence of the twin plates in the TZ confirms that the temperature there was less than 1000 °C.…”

Section: Resultsmentioning

confidence: 99%

Microstructural Evolution and Mechanical Performance of Two Joints of Medium-Mn Stainless Steel with Low- and High-Alloyed Steels

et al. 2023

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In this work, 2 mm thick medium-Mn austenitic stainless steel (MMn–SS) plates were joined with austenitic NiCr stainless steel (NiCr–SS) and low-carbon steel (LCS) using the gas tungsten arc welding technique. A precise adjustment of the welding process parameters was conducted to achieve high-quality dissimilar joints of MMn–SS with NiCr–SS and LCS. The microstructural evolution was studied using laser scanning confocal and electron microscopes. Secondary electron imaging and electron backscatter diffraction (EBSD) techniques were intensively employed to analyze the fine features of the weld structures. The mechanical properties of the joints were evaluated by uniaxial tensile tests and micro-indentation hardness (HIT). The microstructure of the fusion zone (FZ) in the MMn–SS joints exhibited an austenitic matrix with a small fraction of δ-ferrite, ~6%. The tensile strength (TS) of the MMn–SS/NiCr–SS joint is significantly higher than that of the MMn–SS/LCS joint. For instance, the TSs of MMn–SS joints with NiCr–SS and LCS are 610 and 340 MPa, respectively. The tensile properties of MMn–SS/LCS joints are similar to those of BM LCS, since the deformation behavior and shape of the tensile flow curve for that joint are comparable with the flow curve of LCS. The HIT measurements show that the MMn–SS/NiCr–SS joint is significantly stronger than the MMn–SS/LCS joint since the HIT values are 2.18 and 1.85 GPa, respectively.

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Section: Resultsmentioning

confidence: 99%

Microstructural Evolution and Mechanical Performance of Two Joints of Medium-Mn Stainless Steel with Low- and High-Alloyed Steels

et al. 2023

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“…11(a 2 ) and 11(b 2 ) show a considerable amount of lattice distortion associated with plastic deformation including the effect of deformation twins. 23,24) However, the lattice distortion distribution, which can mainly be attributed to the presence of geometrically necessary dislocations, did not show a significant difference between the hydrogen-charged 1DH and 3DH specimens, as demonstrated by the kernel average misorientation (KAM) [25][26][27] and grain reference orientation deviation (GROD) maps 28,29) (Figs. 11(a 3 ) and 11(b 3 ) and Figs.…”

Section: Crack Propagationmentioning

confidence: 96%

Hydrogen-assisted Crack Propagation in Pre-strained Twinning-induced Plasticity Steel: from Initiation at a Small Defect to Failure

et al. 2021

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Hydrogen-assisted crack growth of pre-strained twinning-induced plasticity (TWIP) steel was investigated using artificial defects (micro-drilled holes), which acted as artificial crack initiation sites. Hydrogen was introduced into the specimens by electrochemical hydrogen charging during slow strain rate tensile test. The quasi-cleavage crack propagation observed was due to repeated crack initiation near the crack tip and subsequent coalescence. Crack initiation near the crack tip occurred after plastic deformation of the crack tip, and pre-straining facilitated plasticity-driven crack initiation. The early stage of plasticity-driven crack growth was sensitive to the crack length and remote stress level. Accordingly, the crack growth rate in the early stage increased with the increase in the initial defect size. In the following stage of the crack growth, the crack growth rate exhibited a complicated trend with respect to the crack length, which is possibly due to the plastic-wake-altered stress field around the crack tip, which depends on the initial defect size.

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“…Currently, the twin plates volume fraction increase is attributed to the increased twin plate thicknesses. Nevertheless, increasing the widths of the twin plates is considered as a twin-growth event and not a twinnucleation event (the addition of new twin boundaries), which does not enhance the work hardening rate, similar to the nucleation of fresh twins, because twin-growth requires a much smaller driving force than that utilized during twin nucleation, as concluded in the literature [11,52].…”

Section: The Contribution Of Deformation Mechanisms To the Ow Stressmentioning

confidence: 99%

“…Twins can cause a resistance to dislocation motion, and twin-twin interactions result in a high hardening rate [9,10]. Four deformation mechanisms affect the mechanical properties of Had eld steel including [2,6,11]: (i) lattice friction, (ii) dynamic strain ageing (DSA), (iii) mechanical twinning, and (iv) dislocation accumulations. However, it is challenging in polycrystalline Had eld steel to experimentally identify the contribution of each deformation mechanism as all four mechanisms are generally active, and due to grain boundary effects [12,13].…”

Section: Introductionmentioning

confidence: 99%

Strengthening Contributions of Mechanical Twinning and Dislocations to the Flow Stress of Hadfield High-Manganese Steel: Quantitative Analysis

Khedr

Min

et al. 2022

J. of Materi Eng and Perform

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The ow stress of high C-Mn austenitic steel is attributed to lattice friction, dynamic strain aging (DSA), mechanical twinning and forest hardening. However, it has not been clari ed yet which mechanism quantitatively contributes most to the work hardening of 12.5Mn-1.1C steel. In this study, austenitic Had eld steel (1.1 wt.% C and 12.5 wt.% Mn) was tensile tested at a strain rate of 10 s − 1 . The lattice friction was estimated by the Hall-Petch relationship. DSA effect was neglected because of the high strain rate of deformation. Twin plates characteristics and dislocation densities were estimated quantitatively at different strain levels (11, 18, 25, 38, and 55%). The deformed twin plates were studied by optical and transmission electron microscopies. Dislocation densities were estimated by analyzing the X-ray diffraction patterns using Rietveld analyses. A linear approach was utilized to model the ow stress during the plastic deformation, and it is found that the linear model is consistent with the experimental results. During the early stages of the plastic deformation, the mechanical twinning was the dominant deformation mechanism, and it was more effective to the ow stress than the forest hardening due to the enhancement of the twin nucleation process. However, with increasing the strain level, the thicknesses of the twinned plates were increased rather than the initiation of new twin plates, resulting in a reduced contribution by the mechanical twinning to the ow stress. On the other hand, increasing the dislocation densities with an increase in the strain level was detected, which resulted in an enhanced contribution by forest hardening to the ow stress more than the mechanical twinning.

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Evolution of Fracture Mode in Nano-twinned Fe-1.1C-12.5Mn Steel

Cited by 10 publications

References 43 publications

Microstructural Evolution and Mechanical Performance of Two Joints of Medium-Mn Stainless Steel with Low- and High-Alloyed Steels

Microstructural Evolution and Mechanical Performance of Two Joints of Medium-Mn Stainless Steel with Low- and High-Alloyed Steels

Hydrogen-assisted Crack Propagation in Pre-strained Twinning-induced Plasticity Steel: from Initiation at a Small Defect to Failure

Strengthening Contributions of Mechanical Twinning and Dislocations to the Flow Stress of Hadfield High-Manganese Steel: Quantitative Analysis

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