Positron Annihilation Spectroscopy Study of Carbon-Vacancy Interaction in Low-Temperature Bainite

Rementería, Rosalía; Domínguez‐Reyes, R.; Capdevila, Carlos; García‐Mateo, C.; Caballero, Francisca G.

doi:10.1038/s41598-020-57469-x

Cited by 17 publications

(11 citation statements)

References 53 publications

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“…These can be dislocations or defects associated with them, such as jogs, vacancies [ 35 , 36 , 37 ], and vacancy–solute complexes for steel components (e.g., v-Cr (153 ps), v-Mn (152 ps), v-Cu (153 ps), and v-C (160 ps)) [ 38 , 39 , 40 ]. Moreover, similar positron lifetimes were found for martensite (159 ± 3 ps), bainite (164 ± 3 ps), pearlite (151 ± 3 ps), and austenite (149 ± 3 ps) steel structures [ 41 , 42 ] after different heat treatments. This implies that this lifetime cannot be unequivocally assigned to only one type of defect.…”

Section: Resultssupporting

confidence: 72%

Positron Annihilation Spectroscopy Study of Metallic Materials after High-Speed Cutting

Laptev

Bordulev

et al. 2022

Materials

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During high-speed cutting, a white layer is often produced on the machined surfaces after mechanical machining, seriously affecting the mechanical properties. These properties are related to the material structure and the defects induced by cutting. However, there is a lack of research on the atomic-scale defects of the white layer. This paper studied the influence of cutting parameters, namely the feed rate, cutting speed and cutting depth, on atomic-scale defects induced by high-speed cutting in GCr15 steel. Positron annihilation studies showed typical plastically deformed or tempered carbon steel defects with additional vacancy cluster components. The quantity of these clusters changed with cutting parameters. Furthermore, significant changes were observed in the subsurface region up to 1 µm, occurring as a result of simultaneous phase transformations, deformation and thermal impacts. The predominant accumulation of only one type of atomic-scale defect was not observed.

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Section: Resultssupporting

confidence: 72%

Positron Annihilation Spectroscopy Study of Metallic Materials after High-Speed Cutting

Laptev

Bordulev

et al. 2022

Materials

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“…In line with those results, and by means of positron lifetime spectroscopy, it has been possible to reveal the presence of a significant amount of mono-vacancies in Super-Bainite that could assist in retaining carbon in bainitic ferrite by the formation of C−vacancy complexes (Rementeria, Domínguez-Reyes et al 2020). Due to the low mobility of these complexes in the ferrite, the complete partitioning of carbon towards the austenite/ferrite interface is hindered, and the phenomenon of carbon clustering in the ferritic phase formed at low temperature is promoted.…”

Section: Multiscale Structural Analysis Of Super-bainitesupporting

confidence: 60%

Super-Bainite

Caballero¹,

García‐Mateo²

2022

Encyclopedia of Materials: Metals and Alloys

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In this work, the history of recent developments related to the so-called Super-Bainite or nanocrystalline bainite is reviewed. This microstructure has aroused the interest of the scientific and technological community, due to the intricate and complex characteristics that define its structure, as well as the excellent mechanical properties. It has been needed fundamental studies at the atomic scale to establish the most relevant propertymicrostructure relationships. This work offers a guided journey to understand Superbainite, from the atomic level to full size components.

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“…Therefore, the precipitation of iron carbide (25 at.-% C) in lower bainite occurs within the ferrite tips, which is probably not possible in the present ADI material due to the high silicon content. The cluster positions indicate iron lattice distortions, as C has the tendency to accumulate around them as experimentally proved most recently [ 50 ]. The proxigrams in Figure 12 show a carbon content of less than 0.3 at.-% for all ferrite regions.…”

Section: Resultsmentioning

confidence: 91%

Phase Transition Kinetics in Austempered Ductile Iron (ADI) with Regard to Mo Content

et al. 2020

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The phase transformation to ausferrite during austempered ductile iron (ADI) heat treatment can be significantly influenced by the alloying element Mo. Utilizing neutron diffraction, the phase transformation from austenite to ausferrite was monitored in-situ during the heat treatment. In addition to the phase volume fractions, the carbon enrichment of retained austenite was investigated. The results from neutron diffraction were compared to the macroscopic length change from dilatometer measurements. They show that the dilatometer data are only of limited use for the investigation of ausferrite formation. However, they allow deriving the time of maximum carbon accumulation in the retained austenite. In addition, the transformation of austenite during ausferritization was investigated using metallographic methods. Finally, the distribution of the alloying elements in the vicinity of the austenite/ferrite interface zone was shown by atom probe tomography (APT) measurements. C and Mn were enriched within the interface, while Si concentration was reduced. The Mo concentration in ferrite, interface and austentite stayed at the same level. The delay of austenite decay during Stage II reaction caused by Mo was studied in detail at 400 °C for the initial material as well as for 0.25 mass % and 0.50 mass % Mo additions.

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Positron Annihilation Spectroscopy Study of Carbon-Vacancy Interaction in Low-Temperature Bainite

Cited by 17 publications

References 53 publications

Positron Annihilation Spectroscopy Study of Metallic Materials after High-Speed Cutting

Positron Annihilation Spectroscopy Study of Metallic Materials after High-Speed Cutting

Super-Bainite

Phase Transition Kinetics in Austempered Ductile Iron (ADI) with Regard to Mo Content

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