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C G Park - One of the best experts on this subject based on the ideXlab platform.

  • Influence of Carbon Content on the microstructure, martensitic transformation and mechanical properties in austenite/epsilon-martensite dual-phase Fe-Mn-C steels
    'Elsevier BV', 2018
    Co-Authors: Jb Seol, J E Jung, Y W Jang, C G Park
    Abstract:

    We report on the effects of Carbon Content on the martensitic transformation and its contribution to the work-hardening behavior of Fe-Mn-C steels during tensile deformation based on analysis by X-ray diffraction, electron backscatter diffraction and transmission electron microscopy. Austenite/epsilon-martensite dual-phase Fe-17Mn-C (wt.%) steels containing different Carbon Contents (0.01, 0.10, 0.20 wt.%) were investigated before, during and after tensile deformation. Before deformation, the transformation of austenite to thermally induced epsilon-martensite on cooling was suppressed as the Carbon Content increases. To precisely monitor microstructural changes during deformation, stepwise loading experiments were carried out in combination with electron backscatter diffraction analysis. This approach revealed that with increasing Carbon Content, the kinetics of transformation of gamma phase to deformation stimulated epsilon-martensite became faster, while that of epsilon-martensite to alpha'-martensite was sluggish. We attribute this controversial effect to an increased gamma grain size by the microstructural refinement of thermally induced epsilon-martensite and the reduction of solid solution strengthening effects by the redistribution of solute Carbon. In addition, the dependence of deformation-induced epsilon-martensite on the loading direction differed from that of alpha'-martensite, and the evolution of alpha' morphology was controlled by achieving appropriate levels of strain during stepwise loading. Based on the observations at the surface and inside the bulk after deformation, insights into various deformation-driven displacive phenomena, such as the formation of alpha'-martensite at the nonintersecting parts of two epsilon(initial) bands, the presence of nanotwinned bundles inside austenite, cementite precipitation inside alpha'-martensite, and the origin of the serrated flow in strain stress curves, were obtained. Therefore, the present study is able assist in identifying whether the deformation-induced martensitic transformation varied as a function of Carbon Content and the resulting fracture behavior, thereby enabling us to understand the work-hardening behavior of these steels. Crown Copyright (c) 2012 Published by Elsevier Ltd. on behalf of Acta Materialia Inc. All rights reserved.X1585

  • influence of Carbon Content on the microstructure martensitic transformation and mechanical properties in austenite e martensite dual phase fe mn c steels
    Acta Materialia, 2013
    Co-Authors: Jaebok Seol, J E Jung, Y W Jang, C G Park
    Abstract:

    Abstract We report on the effects of Carbon Content on the martensitic transformation and its contribution to the work-hardening behavior of Fe–Mn–C steels during tensile deformation based on analysis by X-ray diffraction, electron backscatter diffraction and transmission electron microscopy. Austenite/e-martensite dual-phase Fe–17Mn–C (wt.%) steels containing different Carbon Contents (0.01, 0.10, 0.20 wt.%) were investigated before, during and after tensile deformation. Before deformation, the transformation of austenite to thermally induced e-martensite on cooling was suppressed as the Carbon Content increases. To precisely monitor microstructural changes during deformation, stepwise loading experiments were carried out in combination with electron backscatter diffraction analysis. This approach revealed that with increasing Carbon Content, the kinetics of transformation of γ phase to deformation stimulated e-martensite became faster, while that of e-martensite to α’-martensite was sluggish. We attribute this controversial effect to an increased γ grain size by the microstructural refinement of thermally induced e-martensite and the reduction of solid solution strengthening effects by the redistribution of solute Carbon. In addition, the dependence of deformation-induced e-martensite on the loading direction differed from that of α’-martensite, and the evolution of α’ morphology was controlled by achieving appropriate levels of strain during stepwise loading. Based on the observations at the surface and inside the bulk after deformation, insights into various deformation-driven displacive phenomena, such as the formation of α’-martensite at the nonintersecting parts of two e initial bands, the presence of nanotwinned bundles inside austenite, cementite precipitation inside α’-martensite, and the origin of the serrated flow in strain–stress curves, were obtained. Therefore, the present study is able assist in identifying whether the deformation-induced martensitic transformation varied as a function of Carbon Content and the resulting fracture behavior, thereby enabling us to understand the work-hardening behavior of these steels.

Hansjurgen Christ - One of the best experts on this subject based on the ideXlab platform.

  • deformation induced martensite formation during cyclic deformation of metastable austenitic steel influence of temperature and Carbon Content
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008
    Co-Authors: U Krupp, Charles G West, Hansjurgen Christ
    Abstract:

    Abstract To study the influence of the parameters Carbon Content, temperature and total strain amplitude on the deformation-induced martensite formation in metastable 301 austenitic steel, hollow cylindrical fatigue specimens were carburized and decarburized in methane–hydrogen gas mixtures. Fatigue experiments were carried out in a temperature range between RT and T  = −100 °C while monitoring the fraction of deformation-induced martensite versus the number of cycles by means of a magneto-inductive ferrite sensor. The results show that deformation-induced martensite formation leads to pronounced cyclic hardening. A certain amount of accumulated plastic strain is necessary and a threshold value of the plastic strain amplitude must be exceeded to trigger martensitic transformation. The effect of the Carbon Content and/or the temperature on the formation of α′ martensite is very strong in such a way that high Carbon concentrations and elevated temperatures stabilize the austenite phase.

  • strain induced martensite formation in metastable austenitic steels with varying Carbon Content
    Zeitschrift Fur Metallkunde, 2002
    Co-Authors: U Krupp, Charles G West, Huiping Duan, Hansjurgen Christ
    Abstract:

    Abstract Fatigue tests are performed on cylindrical, sheet and foil specimens to investigate the strain-induced martensitic transformation of austenatic steels. The tests set a variety of strain amplitudes and temperatures as well as various Carbon concentrations for the investigated materaals in order to broaden the scope of the martensitic transformation and thereby its characterization. It is confirmed that there is a threshold value of plastic strain amplitude for the investigated materials above which the incremental increase in martensite volume fraction in the specimen under continued cyclic loading is of significance. Block-loading tests indicate that cycles at amplitudes below this threshold do not contribute to the austenite transformation. Thermodynamic calculations are applied in order to provide information on the stability of the material with regard to Carbon Content. It is shown that Carbon concentration can be established by gas charging of the materials so that the driving force for tran...

Masao Kunioka - One of the best experts on this subject based on the ideXlab platform.

  • accuracy of biobased Carbon Content of determination of plastic products and related materials by accelerator mass spectrometry
    Polymer Degradation and Stability, 2014
    Co-Authors: Masahiro Funabashi, Keiichi Ohara, Masao Kunioka
    Abstract:

    Abstract Biobased Content of plastic products and related materials were determined according to ISO 16620 series. Biobased Carbon Content of sample was determined from percent modern Carbon (pMC). pMC was determined by Carbon-14 (14C) concentration measured by accelerator mass spectrometry (AMS). The error of pMC was discussed. The error of biobased Carbon Content was also discussed in order to confirm repeatability, reproducibility and accuracy. The standard deviation of pMC of samples shown in this study is less than 1% except for rubber/polymer composite samples. The standard deviation of pMC of rubber/polymer composites is less than 3%. When the pMC of source material was employed as a reference of pMC, the derived biobased Carbon Content from pMC agree well with theoretical value within 3% error. Biobased synthetic polymer Content of sample was determined from biobased Carbon Content. Biobased mass Content of sample was determined from biobased Carbon Content. Accuracies of biobased synthetic polymer Content and biobased mass Content for composite samples with two components were less than 3%.

  • Biobased Carbon Content of resin extracted from polyethylene composite by Carbon-14 concentration measurements using accelerator mass spectrometry
    SpringerPlus, 2014
    Co-Authors: Kazuhiro Taguchi, Masahiro Funabashi, Masao Kunioka, Fumi Ninomiya
    Abstract:

    An estimation procedure for biobased Carbon Content of polyethylene composite was studied using Carbon-14 (^14C) concentration ratios as measured by accelerated mass spectrometry (AMS). Prior to the measurement, additives and fillers in composites should be removed because they often contain a large amount of biobased Carbon and may shift the estimation. Samples of resin with purity suitable for measurement were isolated from composites with a Soxhlet extractor using heated cyclohexanone. After cooling of extraction solutions, the resin was recovered as a fine semi-crystalline precipitate, which was easily filtered. Recovery rates were almost identical (99%), even for low-density polyethylene and linear low-density polyethylene, which may have lower crystallinity. This procedure could provide a suitable approach for estimation of biobased Carbon Content by AMS on the basis of the standard ASTM D 6866. The biobased Carbon Content for resin extracted from polyethylene composites allow for the calculation of biosynthetic polymer Content, which is an indicator of mass percentage of the biobased plastic resin in the composite.

Jaebok Seol - One of the best experts on this subject based on the ideXlab platform.

  • influence of Carbon Content on the microstructure martensitic transformation and mechanical properties in austenite e martensite dual phase fe mn c steels
    Acta Materialia, 2013
    Co-Authors: Jaebok Seol, J E Jung, Y W Jang, C G Park
    Abstract:

    Abstract We report on the effects of Carbon Content on the martensitic transformation and its contribution to the work-hardening behavior of Fe–Mn–C steels during tensile deformation based on analysis by X-ray diffraction, electron backscatter diffraction and transmission electron microscopy. Austenite/e-martensite dual-phase Fe–17Mn–C (wt.%) steels containing different Carbon Contents (0.01, 0.10, 0.20 wt.%) were investigated before, during and after tensile deformation. Before deformation, the transformation of austenite to thermally induced e-martensite on cooling was suppressed as the Carbon Content increases. To precisely monitor microstructural changes during deformation, stepwise loading experiments were carried out in combination with electron backscatter diffraction analysis. This approach revealed that with increasing Carbon Content, the kinetics of transformation of γ phase to deformation stimulated e-martensite became faster, while that of e-martensite to α’-martensite was sluggish. We attribute this controversial effect to an increased γ grain size by the microstructural refinement of thermally induced e-martensite and the reduction of solid solution strengthening effects by the redistribution of solute Carbon. In addition, the dependence of deformation-induced e-martensite on the loading direction differed from that of α’-martensite, and the evolution of α’ morphology was controlled by achieving appropriate levels of strain during stepwise loading. Based on the observations at the surface and inside the bulk after deformation, insights into various deformation-driven displacive phenomena, such as the formation of α’-martensite at the nonintersecting parts of two e initial bands, the presence of nanotwinned bundles inside austenite, cementite precipitation inside α’-martensite, and the origin of the serrated flow in strain–stress curves, were obtained. Therefore, the present study is able assist in identifying whether the deformation-induced martensitic transformation varied as a function of Carbon Content and the resulting fracture behavior, thereby enabling us to understand the work-hardening behavior of these steels.

Tadashi Furuhara - One of the best experts on this subject based on the ideXlab platform.