Papers by Keyword: Profile Analysis

Abstract: The dislocation density of plastically deformed oxygen free copper (OFC) was evaluated by X-ray diffraction profile analysis with synchrotron radiation. The modified Williamson-Hall and modified Warren-Averbach methods were applied to the analysis. The dislocation densities of OFC samples with compressive plastic strains of 1 % and 4 % were 5.1×10¹⁴ m^-2 and 9.2×10¹⁴ m^-2, respectively.

Abstract: Microstructural change during hot compressive deformation at 700 oC followed by isothermal annealing for a Fe-32Ni austenitic alloy was monitored using in situ neutron diffraction. The evolution of deformation texture with 40% compression and its change to recrystallization texture during isothermal annealing were presented by inverse pole figures for the axial and radial directions. The change in dislocation density was tracked using the convolutional multiple whole profile fitting method. To obtain the fitting results with good accuracies, at least 60 s time-interval for slicing the event-mode recorded data was needed. The average dislocation density in 60 s after hot compression was determined to be 2.8 x 10¹⁴ m^-2, and it decreased with increasing of annealing time.

Abstract: A relationship between dislocation density and macro strain was investigated for GLIDCOP, dispersion-strengthened copper with ultra-fine particles of aluminum oxide. The dislocation density was estimated by applying the Warren-Averbach method to a diffraction profile measured using synchrotron radiation.

Abstract: A ductile damage progress of FCC single crystal was verified by a profile analysis using white X-ray obtained in BL28B2 beam line of SPring-8. In this study, an aluminum single crystal of the purity 6N was used as a specimen prepared in I-type geometry for tensile test. A notch was introduced into one side of the center of a parallel part of the specimen by the wire electric discharge machining. White X-ray, which has 100 microns in height and 200 microns in width, was incident into the specimen on the Bragg angle θ of 3 degrees using energy dispersive X-ray diffraction technique. The specimen was deformed by elongation along crystal orientation [001], and a diffraction profile of the white X-ray which penetrated it was analyzed. In profile analysis, an instrumental function was defined in consideration both of a divergence by a slit and a response function peculiar to the energy dispersive method. The Gauss component of integral breadth related to non-uniform strain and the Cauchy component of integral breadth related to crystallite size were determined by eliminating the broadening by the instrumental function from the diffraction profile of white X-ray. As a result, the direction of progress and the characteristics of ductile damage near the notch of the aluminum single crystal were clarified from the Gauss component and the Cauchy component of integral width of the single diffraction profile.

Abstract: Fully austenitic steels of the Fe-Mn-C system can show extensive deformation twinning (TWIP effect). The deformed microstructure of such steels has been analysed using X-ray diffraction at the European Synchrotron Radiation Facility (ESRF). The experimental diffractograms, recorded using a 2D CCD camera, are analysed in terms of Bragg peak profiles (broadening and asymmetry) and position (shift from the reference [undeformed state] position) leading to an estimation of dislocation and stacking faults densities.

Abstract: Dislocation density and crystallite size of steel wires with various carbon concentrations and drawing strains were determined by profile analyses for neutron diffraction profiles. The density is found to increase while the size decreases with increasing of carbon concentration and/or drawing strain. Both of the Bailey-Hirsch relation and Hall-Petch relation hold for the present results to suggest that these two are not independent., i.e., indicating an identical strengthening mechanism from a different point of view.