Line profile analysis of synchrotron X-ray diffraction data of iron powder with bimodal microstructural profile parameters

Bhakar, Ashok; Gupta, Pooja; Rao, P. Nageswara; Swami, M. K.; Tiwari, Pragya; Ganguli, Tapas; K., S.

doi:10.1107/s1600576721000601

Cited by 4 publications

(3 citation statements)

References 91 publications

(200 reference statements)

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“…The importance of using this approach (by including the IRF) is that a maximum of four TCH parameters, I G , Y, U and X, are sufficient for determining the sample-related isotropic peak profile contributions, and this has been followed extensively in the literature (Thompson et al, 1987;Rodrı ´guez-Carvajal & Roisnel, 2004;Kaduk & Reid, 2011;Bhakar et al, 2017Bhakar et al, , 2021Denney et al, 2022).…”

Section: Peak Shape Analysis Methodologiesmentioning

confidence: 99%

“…WPPF is a relatively new method among BBMs and is regularly used for Rietveld refinement (Rietveld, 1967(Rietveld, , 1969. It has the advantage of simultaneous refinement of both structural and microstructural parameters (de Keijser et al, 1983;Young & Sakthivel, 1988;Lutterotti & Scardi, 1990;Bhakar et al, 2016Bhakar et al, , 2017Scardi et al, 2018;Bhakar et al, 2021). In this approach, however, empirical peak profile functions (like pseudo-Voigt) are used for profile fitting, limiting its accountability.…”

Section: Introductionmentioning

confidence: 99%

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Significance of diffraction peak shapes in determining crystallite size distribution: a peak shape analysis procedure for pseudo-Voigt profiles and its application

Bhakar,

Taxak,

Rai

2023

J Appl Cryst

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The width (or breadth) and shape of a diffraction peak are two important characteristics to describe a peak profile. These features are directly associated with the microstructural (size and strain) properties of a material. It is important to separate the contributions of crystallite size and microstrain from the diffraction peak profiles in order to establish their correlation with the physical properties of the sample. While procedures to deconvolve the widths of a diffraction peak profile are extensively documented in the literature, the shape part of the peak profile is usually ignored. In the present work an approach for a quantitative estimation of the peak shape contribution made by crystallite size is discussed to complement the information available via the existing breadth-based methods (BBMs). A relationship between the shape of a diffraction peak profile and the crystallite size distribution for a nanomaterial is presented, which was not hitherto available in the literature. It is shown that the commonly observed difference between crystallite sizes obtained using the Scherrer equation considering two different definitions of peak width, i.e. full width at half-maximum and integral breadth, is also associated with this peak shape parameter. Thus, knowledge of the peak shape has a vital role in microstructural understanding. Therefore, in this work a procedure to isolate the shape part of a diffraction peak profile is described in connection with the existing BBMs used for microstructural analysis. This study further aims to utilize the information on these peak shapes to provide comprehensive details of the effect of crystallite size by considering a log-normal distribution to complement the BBMs. Applications of this approach are shown using several worked examples of practical situations from the literature.

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Section: Peak Shape Analysis Methodologiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Significance of diffraction peak shapes in determining crystallite size distribution: a peak shape analysis procedure for pseudo-Voigt profiles and its application

Bhakar,

Taxak,

Rai

2023

J Appl Cryst

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“…Recently, this beamline was used to study the microstructure of iron powder using line profile analysis. The super-Lorentzian peak shape of single-phase Fe powder was ascribed to two microstructures having different microstrains (Bhakar et al, 2021).…”

Section: Angle-dispersive X-ray Diffraction (Adxrd) Measurementmentioning

confidence: 97%

BL-02: a versatile X-ray scattering and diffraction beamline for engineering applications at Indus-2 synchrotron source

et al. 2021

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A hard X-ray engineering applications beamline (BL-02) was commissioned recently and started operation in March 2019 at the Indian synchrotron source, Indus-2. This bending-magnet-based beamline is capable of operating in various beam modes, viz. white, pink and monochromatic beam. The beamline utilizes the X-ray diffraction technique in energy-dispersive and angle-dispersive modes to carry out experiments mainly focused on engineering problems, viz. stress measurement, texture measurement and determination of elastic constants in a variety of bulk as well as thin-film samples. An open-cradle six-circle diffractometer with ∼12 kg load capacity allows accommodation of a wide variety of engineering samples and qualifies the beamline as a unique facility at Indus-2. The high-resolution mode of this beamline is suitably designed so as to carry out line profile analysis for characterization of micro- and nano-structures. In the present article the beamline is described starting from the beamline design, layout, optics involved, various operational modes and experimental stations. Experiments executed to validate the beamline design parameters and to demonstrate the capabilities of the beamline are also described. The future facilities to be incorporated to enhance the capabilities of the beamline are also discussed.

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Bimodal microstructural characterization of Si powder using X-ray diffraction: the role of peak shape

Bhakar,

Srivastava,

Tiwari

et al. 2024

Powder Diffr.

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X-ray diffraction (XRD) characterization of Si powder was carried out using synchrotron and laboratory sources. Microstructural (size-strain) analyses of XRD patterns were carried out using the Rietveld refinement method. Experimentally observed super-Lorentzian shapes of the XRD peaks of Si powder were examined using multimodal profile fitting and bimodal model was found to be adequate. The two components obtained using a bimodal approach are referred as narrow and broad profiles based on their estimated relative peak widths. Peak shapes of crystallite size-dependent parts of narrow and broad profiles were found to be almost Gaussian and Lorentzian in nature, respectively. The simultaneous presence of such peak shapes corresponding to a bimodal microstructure is uncommon in literature. Therefore, in order to explore the role of different natures of XRD peak shapes (size dependent) of the bimodal profiles of Si, detailed microstructural analysis was carried out using the complementary method of whole powder pattern modeling (WPPM) and found to be related to the variance of crystallites' size distribution. Additionally, the effect of instrument resolution (laboratory and synchrotron sources) on the microstructural parameters was also studied. Scanning and transmission electron microscopy were used to characterize the morphology of Si powder and correlate with the microstructural findings of XRD methods.

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Line profile analysis of synchrotron X-ray diffraction data of iron powder with bimodal microstructural profile parameters

Cited by 4 publications

References 91 publications

Significance of diffraction peak shapes in determining crystallite size distribution: a peak shape analysis procedure for pseudo-Voigt profiles and its application

Significance of diffraction peak shapes in determining crystallite size distribution: a peak shape analysis procedure for pseudo-Voigt profiles and its application

BL-02: a versatile X-ray scattering and diffraction beamline for engineering applications at Indus-2 synchrotron source

Bimodal microstructural characterization of Si powder using X-ray diffraction: the role of peak shape

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