Comparison of the Measurements of Austenite Volume Fraction by Various Methods for Mn-Si-C Steel

Abstract

Synopsis : Variousmethodswereemployedtomeasuretheaustenitevolumefractionina1.5Mn-1.5Si-0.2Csteel.Ithasbeenconfirmedthatthevolume fractions determined by transmission electron microscopy, scanning electron microscopy/electron back scatter diffraction, X-ray diffraction and neutron diffraction exhibit a general trend to become larger in this order, although the values obtained by X-ray and neutron diffraction are similar in the present steel because austenite is relatively stable. The austenite volume fractions determined by diffraction methods have been found to be affected by the measuring specimen direction, i.e., texture, even by applying the conventional correcting procedure. To avoid thisinfluence,itisrecommendedtomeasurebothofvolumefractionandtexturesimultaneouslyusingneutrondiffraction.Althoughsyn-chrotronX-rayshowshigherangleresolution,itssmallincidentbeamsizebringspoorstatisticreliability.Theinfluenceoftexturecannotbe avoided for transmission Bragg edge measurement, either, which must be overcome to realize 2D or 3D volume fraction mapping.

<i>In situ</i> Observations of Transformation Behavior upon Heating for a 1.5Mn-1.5Si-0.2C Steel -Comparison between Neutron Diffraction, XRD, EBSD and Dilatometry-

“…Microstructures before heating were reported in another paper 21) and then briefly explained here in Fig. 1.…”

“…The absence of the retained austenite was also confirmed by X-ray and neutron diffraction as reported in ref. 21. Therefore, in the present annealing experiments, TR1 and TR2 are predicted to show minor difference and therefore interesting is to compare TR1 or TR2 with TR3.…”

“…The details on the specimen preparation were reported elsewhere 21) and hence brief explanation is given here. The chemical compositions of the steel were 0.20C-1.50Mn-1.52Si-0.009P-0.001S mass%, prepared referring to Sugimoto et al's report.…”

Crystallographic characterization of steel microstructure using neutron diffraction

“…Hence, they measured TOF profiles from 525 directions in order to determine orientation distribution function (ODF) and fγ simultaneously employing the MAUD software [28,29]. Their conclusion has been reconfirmed in Ref [5] by comparing the results of neutron diffraction with those of transmission electron microscopy (TEM), electron backscatter diffraction (EBSD) and laboratory and synchrotron X-ray diffractions. This ex situ neutron diffraction measurement will be explained in Chapter 2.…”

“…This review is focused on neutron diffraction emphasizing how it is becoming useful to obtain global microstructural information in situ during material processing, which have been obtained through a project commissioned by the Innovative Structural Materials Association (ISMA)/New Energy and Industrial Technology Development Organization (NEDO) [4]. More details can be found in references [5][6][7][8][9].…”