Lath formation mechanisms and twinning as lath martensite substructures in an ultra low-carbon iron alloy

Ping, Dehai; Guo, Shuqi; Imura, Masahito; Liu, X.; Ohmura, Takahito; Ohnuma, Masato; Lü, Xing; Abe, Taichi; Onodera, Hidehiro

doi:10.1038/s41598-018-32679-6

Cited by 36 publications

(11 citation statements)

References 32 publications

(37 reference statements)

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“…The orientation of the NW is not completely random because the diffraction spots indicated by the blue and red rectangles in Figure are assignable to ones when it is rotated ±20° and ±25° with the growth direction as an axis. The unusual orientation that is not a common habit plane in bulk − is probably due to a sizable uniaxial anisotropy (NW shape) that causes different stress as compared to that of bulk. In order to make thinner single-crystal Fe NWs, a more suitable precursor such as an organometallic compound is needed to decrease the growth temperature because Fe NWs could grow only at around 800 °C as long as FeCl 2 was used as the precursor.…”

Section: Resultsmentioning

confidence: 99%

Growth Kinetics and Magnetic Property of Single-Crystal Fe Nanowires Grown via Vapor–Solid Mechanism Using Chemically Synthesized FeO Nanoparticle Catalysts

Yanase

Ogihara

Awashima

et al. 2019

Crystal Growth & Design

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Single-crystal Fe nanowires (NWs) were synthesized on SiO 2 /Si substrates by chemical vapor deposition (CVD) using a two-flow system in the presence of FeO nanoparticles as catalysts. Transmission electron microscopy observations and an electron diffraction analysis revealed that the NW was defect-free α-Fe (bcc structure) oriented in the ⟨100⟩ direction. A plausible mechanism of the Fe NW growth is suggested based on the observations of the morphology and characteristic diameter of the Fe NW. We found that the NWs became polycrystalline when their diameter was approximately 100 nm. The excellent crystal quality of the single-crystal NW was confirmed by electron diffraction and the residual resistance ratio. Magnetic uniformity and a strong shape-anisotropic behavior of magnetization were observed by measuring the hysteresis loop and the angle dependence of the magneto-optical Kerr effect, respectively.

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Section: Resultsmentioning

confidence: 99%

Growth Kinetics and Magnetic Property of Single-Crystal Fe Nanowires Grown via Vapor–Solid Mechanism Using Chemically Synthesized FeO Nanoparticle Catalysts

Yanase

Ogihara

Awashima

et al. 2019

Crystal Growth & Design

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“…The dislocations, as the common substructure along with the uncommon {112} < 111 > type nanotwins, were observed in the martensitic laths of the heat-treated specimens. It has been reported that the twins were initially formed at the M s and then transformed into laths with internal dislocations during the subsequent auto-tempering process [26]. The M s of the TIQ-treated specimen was measured to be lower than that of the DQ-treated one, and the auto-tempering of twins was consequently restrained during the TIQ treatment.…”

Section: Quenching Effect On Microstructurementioning

confidence: 94%

Enhancement of Strength–Ductility Balance of the Laser Melting Deposited 12CrNi2 Alloy Steel Via Multi-step Quenching Treatment

Zhang

Dong

Kang

et al. 2021

Acta Metall. Sin. (Engl. Lett.)

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A ferrite-austenite 12CrNi2 alloy steel additively manufactured by laser melting deposition (LMD) was heat treated by direct quenching (DQ) and tempering inter-critical quenching (TIQ) at 800 °C for enhancing its strength-ductility balance. Both heat-treated alloy steels have the martensite-ferrite dual-phase (DP) microstructures. The volume fractions of martensite in the two treated alloy steels are nearly similar (~ 85 vol%), while the sizes of the prior austenitic grain for martensite are different. The martensite-dominated DP microstructure resulted in an obvious improvement in strength-ductility balance of the alloy steel. Compared with the DQ treatment, the multi-step TIQ treatment caused the strength-ductility balance of the alloy steel to be enhanced due to its higher total elongation. The better ductility of the TIQ-treated alloy steel can be attributed to the optimization of the microstructure. The preferred orientation of ferritic grain in the as-deposited alloy steel which was adverse to plastic deformation through dislocation slip was eliminated via the multi-step TIQ treatment. Moreover, the TIQ treatment promoted the formation of finer-grained martensite with larger areas of grain boundaries and twinning boundaries which resulted in the enhancement of the coordinated deformability of the martensite with the ferrite.

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“…However, in the Fe-C system, there are various reports, and the correlation between a lower transformation point and twinning has not necessarily been obtained. Recently, it is reported by Ping et al that the lath martensite seems to have the twins as the dominant microstructural feature in the low-carbon Fe-0.1%C alloys quenched at temperatures only from 1323K to 1473K [16]. Under the TEM observations, several types of twinned morphologies such as short twins normally inclined to the lath boundary, and long twins having more straight or flat boundary planes are reported.…”

Section: Introductionmentioning

confidence: 95%

Characterization of hierarchical lath martensite microstructure in low carbon steels using ultra-high voltage TEM and SEM-EBSD analysis

Sugiyama

Takei

Sekida

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Lath martensite is a heterogenous microstructure in low carbon steels and plays an important part in microstructure for the high strength steels. The complex martensitic structure has been clarified as the hierarchical block and packet structures using SEM observations and electron backscatter diffraction (EBSD) analysis. As the result of variant analysis, it is found that the block consists of sub-blocks and the block size and distribution seem to be new key factors to control the mechanical properties. Each block is further subdivided by laths, which are the finest structural units in lath martensite. The morphology of laths and their variants in low carbon steels has been further investigated using the ultra-high voltage TEM (UHVEM) with 3MeV in accelerated voltage. Based on a comparison of UHVEM and SEM observations for the same field of view, it is found that the laths have a further hierarchical organization with twinned morphology and the fragmented structure within the laths. Two plane crystal analysis of the twin in a lath has been carried out using SEM-EBSD analysis after Xe-FIB large area fabrication process, resulting in the identification of the twin morphology such as the {112} twin plane perpendicular to the {110} habit plane and along the <111> direction. Although several types of twinned morphology such as the long and short length are observed in the lath microstructure under TEM observations, the twinning structure observed in various forms is explained by a simple model in the present study.

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Lath formation mechanisms and twinning as lath martensite substructures in an ultra low-carbon iron alloy

Cited by 36 publications

References 32 publications

Growth Kinetics and Magnetic Property of Single-Crystal Fe Nanowires Grown via Vapor–Solid Mechanism Using Chemically Synthesized FeO Nanoparticle Catalysts

Growth Kinetics and Magnetic Property of Single-Crystal Fe Nanowires Grown via Vapor–Solid Mechanism Using Chemically Synthesized FeO Nanoparticle Catalysts

Enhancement of Strength–Ductility Balance of the Laser Melting Deposited 12CrNi2 Alloy Steel Via Multi-step Quenching Treatment

Characterization of hierarchical lath martensite microstructure in low carbon steels using ultra-high voltage TEM and SEM-EBSD analysis

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