The crystallography of the austenite-ferrite/carbide transformation in Fe−Cr−C alloys

Howell, P. R.; Bee, J. V.; Honeycombe, R. W. K.

doi:10.1007/bf02811976

Cited by 65 publications

(13 citation statements)

References 6 publications

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“…In addition, originating from the compression deformation martensite as well as ferrite have a distinct orientation relation with the austenite phase. This has been found in most iron based alloys [20][21][22][23]. Here the bcc ferrite, bct martensite and fcc austenite are often observed to have a Kurdjumov-Sachs (K-S) and NishiyamaWassermann (N-W) orientation relationship.…”

Section: Resultsmentioning

confidence: 85%

Strain Induced Martensitic Transformation in Austempered Ductile Iron (ADI)

Saal

Gan

et al. 2016

J. Phys.: Conf. Ser.

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The strain induced martensitic transformation in austempered ductile iron (ADI) has been investigated using high resolution neutron diffraction on samples compressed ex-situ to different plastic strains. In addition bulk texture measurements using neutron diffraction have been performed to calculate the orientation distribution of ferrite and austenite phases for different strain levels. Combing the detailed texture information with neutron diffraction pattern proved to be essential for quantitative phase analysis and extraction of martensite phase fractions. The martensite content induced by strain in ADI depends on austempering temperature and degree of deformation.

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Section: Resultsmentioning

confidence: 85%

Strain Induced Martensitic Transformation in Austempered Ductile Iron (ADI)

Saal

Gan

et al. 2016

J. Phys.: Conf. Ser.

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“…So far, no other studies have reported any eutectoid reaction in Mn-Al steels, only in Cr steels. [7] The eutectoid reaction features the decomposition of the austenite into ferrite and M 23 C 6 carbide. The product phases nucleate and grow at the austenitic grain boundaries, form pearlitic lamellae, and advance into the austenitic matrix.…”

Section: Resultsmentioning

confidence: 99%

“…The M 23 C 6 plates replaced the lamellar M 3 C grains and embedded in the ferritic grains of the pearlite. [7] A well-known Kurdjumov-Sachs (K-S) orientation relationship was proposed to exist between the layer ferrite and M 23 C 6 grains, i.e., (110) a // (111) C6 and [111] a // [011] C6 .…”

Section: Introductionmentioning

confidence: 99%

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A Eutectoid Reaction for the Decomposition of Austenite into Pearlitic Lamellae of Ferrite and M23C6 Carbide in a Mn-Al Steel

Cheng

Hwang

2011

Metall Mater Trans A

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We discovered a eutectoid reaction in an Fe-13.4Mn-3.0Al-0.63C (wt pct) steel after solution heat treatment at 1373 K (1100°C) and holding at temperatures below 923 K (650°C). The steel is single austenite at temperatures from 1373 K to 923 K (1100°C to 650°C). A eutectoid reaction involves the replacement of the metastable austenite by a more stable mixture of ferrite and M 23 C 6 phases at temperatures below 923 K (650°C). The mixture of ferrite and M 23 C 6 is in the form of pearlitic lamellae. The morphology of the lamellae of the product phases is similar to that of pearlite in steels. Thus, we found a new pearlite from the eutectoid reaction of the Mn-Al steel featuring c fi a + M 23 C 6 . A Kurdjumov-Sachs (K-S) orientation relationship exists between the pearlitic ferrite (a) and M 23 C 6 (C6) grains, i.e., (110) a // (111) C6 and [111] a // [011] C6 . The upper temperature limit for the eutectoid reaction is between 923 K and 898 K (650°C and 625°C).

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“…Observaron dos modos de formación de austenita en muestras tratadas a 870 °C en 10 segundos: el primero en los puntos triples de los bordes de grano en la vecindad con los carburos (detectaron fase γ que transforma a α durante el templado) y el segundo directamente alrededor de algunos de los carburos (austenita retenida, Figura 12.a). El hecho que la austenita fuera retenida con el templado los llevó a sugerir que el material tenía un alto contenido de C y Cr en esas zonas lo cual coincide con los resultados de HOWELL et al [15] quienes afirman que la estabilización de la austenita puede depender de la presencia de C y un nivel significativo de un fuerte formador de carburos. Cuando SHTANSKY et al [14] observaron muestras que habían estado a 870 °C durante 100 segundos, a 1000 °C durante 20 segundos y a 1150 °C durante 10 segundos, encontraron una capa de ferrita alrededor de los carburos que se estaban disolviendo (Figura 12.b).…”

Section: Discussionunclassified

Estudio de la microestructura de un cordón de soldadura de un acero P91 mediante microscopía electrónica de transmisión

et al. 2018

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RESUMENEn el presente trabajo se llevó a cabo la caracterización microestructural de un cordón de pasada simple de un acero 9Cr1MoVNb P91 obtenido por el proceso de soldadura semiautomática bajo protección gaseosa (FCAW), en la condición "as welding" mediante microscopía electrónica de transmisión.El acero P91 tiene una buena soldabilidad, pero las propiedades mecánicas de las uniones soldadas son inferiores a las del material base. La zona afectada por el calor (ZAC) de este tipo de aceros es de  4 mm lo que dificulta extraer réplicas y láminas delgadas para el estudio de las distintas microestructuras generadas en cada sub-zona de la ZAC: ZAC de grano grueso (ZACGG), ZAC de grano fino (ZACGF) y ZAC intercrítica (ZACIC). No obstante, fue posible extraer réplicas de cada región para identificar a los precipitados y por medio de la utilización de un haz de iones focalizados (FIB-SEM) se pudieron extraer láminas delgadas de un área específica para caracterizar la microestructura de la matriz. Se caracterizaron los precipitados presentes en cada sub-zona de la ZAC y cómo la disolución del M 23 C 6 afecta a la matriz que lo rodea. A bajas temperaturas pico y bajas velocidades de calentamiento/enfriamiento tales como las que caracterizan a las zonas de grano fino (ZACIC y ZACGF) se encontró austenita retenida en contacto de los carburos M 23 C 6 parcialmente disueltos. Por otra parte, en las zonas con más altas temperaturas pico y altas velocidades de calentamiento/enfriamiento (ZACGG y zona fundida) se encontraron pelícu-las finas de austenita retenida en los ex bordes de grano austenítico y en los listones de martensita. Palabras clave: acero 9Cr1Mo, cordón de soldadura, microscopía electrónica. ABSTRACTIn the present work the microstructural characterization of a single-pass weld of 9Cr1MoVNb P91 steel performed by the flux-cored arc welding (FCAW) process in the "as welding" condition has been carried out by means of transmission electron microscopy.P91 steel offers a good weldability, but the mechanical properties of the welded joints are found to be inferior compared to the base metal. The heat affected zone (HAZ) of these types of steels is  4 mm making it difficult to extract carbon replicas and thin foil to study the microstructure generated in each sub-zone of the ZAC: coarse grained ZAC (CGZAC), fine grained ZAC (FGZAC) and intercritical ZAC (ICZAC). Nevertheless, it was possible to extract replicas from each region to identify precipitates and using a focused ion beam (FIB-SEM), thin films could be extracted from a specific area to characterize the matrix microstructure.The precipitates present in each subzone of the ZAC were characterized as well as how the dissolution of M 23 C 6 affects the matrix. At low peak temperatures and low heating / cooling rates such as those characterizing the fine grain zones (ICHAZ and FGHAZ) the M 23 C 6 carbides were found to be partially dissolved and in contact with retained austenite. On the other hand, in the areas with the highest peak temperatures and high

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The crystallography of the austenite-ferrite/carbide transformation in Fe−Cr−C alloys

Cited by 65 publications

References 6 publications

Strain Induced Martensitic Transformation in Austempered Ductile Iron (ADI)

Strain Induced Martensitic Transformation in Austempered Ductile Iron (ADI)

A Eutectoid Reaction for the Decomposition of Austenite into Pearlitic Lamellae of Ferrite and M23C6 Carbide in a Mn-Al Steel

Estudio de la microestructura de un cordón de soldadura de un acero P91 mediante microscopía electrónica de transmisión

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