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Austenite

About: Austenite is a research topic. Over the lifetime, 36691 publications have been published within this topic receiving 514814 citations. The topic is also known as: gamma-phase iron.


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Journal ArticleDOI
TL;DR: In this paper, the authors reviewed the strengthening mechanisms associated with the various components of martensitic microstructures in steels and other ferrous alloys and examined the experiments and strengthening theories associated with FeNi and FeNi-C alloys, in which the martensite, because of subzero temperatures, can be evaluated with carbon atoms trapped in octahedral interstitial sites.
Abstract: This paper reviews the strengthening mechanisms associated with the various components of martensitic microstructures in steels and other ferrous alloys. The first section examines the experiments and strengthening theories associated with Fe–Ni and Fe–Ni–C alloys, in which the martensite, because of subzero Ms temperatures, can be evaluated with carbon atoms trapped in octahedral interstitial sites. The evaluation of strengthening in these alloys has been limited to interpreting yield strength of unaged, untempered martensite in terms of interstitial solid solution strengthening. The second section reviews strengthening of martensitic Fe–C alloys and low-alloy carbon steels with above-room-temperature Ms temperatures. In these alloys, it is impossible to prevent C diffusion during quenching, and strengthening of martensite becomes dependent on static and dynamic strain aging due to carbon atom interaction with dislocation substructure. In all alloys the dominant strengthening component of martensitic microstructures is the matrix of martensitic crystals, either in lath or plate morphology, but secondary effects due to other microstructural components such as carbides and retained austenite are also discussed.

720 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of external stress and stacking fault energies (SFE) on the width of the stacking faults were analyzed and an excellent correlation between the calculations and actual microstructures examined by scanning electron microscopy was found.

678 citations

Journal ArticleDOI
08 Sep 2017-Science
TL;DR: The deformed and partitioned (D and P) process produced dislocation hardening but retained high ductility, both through the glide of intensive mobile dislocations and by allowing us to control martensitic transformation.
Abstract: A wide variety of industrial applications require materials with high strength and ductility. Unfortunately, the strategies for increasing material strength, such as processing to create line defects (dislocations), tend to decrease ductility. We developed a strategy to circumvent this in inexpensive, medium manganese steel. Cold rolling followed by low-temperature tempering developed steel with metastable austenite grains embedded in a highly dislocated martensite matrix. This deformed and partitioned (D and P) process produced dislocation hardening but retained high ductility, both through the glide of intensive mobile dislocations and by allowing us to control martensitic transformation. The D and P strategy should apply to any other alloy with deformation-induced martensitic transformation and provides a pathway for the development of high-strength, high-ductility materials.

673 citations

Journal ArticleDOI
TL;DR: The morphology and crystallography of lath martensite in two Mn-containing interstitial free steels and a maraging steel were examined in detail by a combination of transmission electron microscopy, electron backscatter diffraction in a scanning electron microscope and optical microscopy.

641 citations

Journal ArticleDOI
TL;DR: In this paper, a novel concept for the heat treatment of martensite, different to customary quenching and tempering, is described, which can be used to generate microstructures with martensites/austenite combinations giving attractive properties.
Abstract: A novel concept for the heat treatment of martensite, different to customary quenching and tempering, is described. This involves quenching to below the martensite-start temperature and directly ageing, either at, or above, the initial quench temperature. If competing reactions, principally carbide precipitation, are suppressed by appropriate alloying, the carbon partitions from the supersaturated martensite phase to the untransformed austenite phase, thereby increasing the stability of the residual austenite upon subsequent cooling to room temperature. This novel treatment has been termed ‘quenching and partitioning’ (Q&P), to distinguish it from quenching and tempering, and can be used to generate microstructures with martensite/austenite combinations giving attractive properties. Another approach that has been used to produce austenite-containing microstructures is by alloying to suppress carbide precipitation during the formation of bainitic structures, and interesting comparisons can be made between the two approaches. Moreover, formation of carbide-free bainite during the Q&P partitioning treatment may be a reaction competing for carbon, although this could also be used constructively as an additional stage of Q&P partitioning to form part of the final microstructure. Amongst the ferrous alloys examined so far are medium carbon bar steels and low carbon formable TRIP-assisted sheet steels.

618 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,422
20222,877
20211,532
20201,843
20191,965
20181,767