Characterisation of microstructure of isothermal martensite formed at low temperature in powder of Fe–23Ni–3.3Mn alloy by Rietveld method

Lattice imperfections in intermetallic Ti–Al alloys: an X-ray diffraction study of the microstructure by the Rietveld method

“…In continuation of recent studies on the microstructural characterization of the industrially important structural materials, namely martensites in Fe-Ni-Mn, Fe-Mn-C and AISI type 300 steel [14][15][16][17][18], by analyzing the X-ray diffraction (XRD) pattern through the Rietveld whole profile fitting method [19,20], the author has undertaken the study of the microstructure in terms of various lattice defect parameters (crystallite size, rms strain, stacking and twin fault probabilities, etc) in three intermetallic titanium aluminides, having compositions close to (Ti:AlZ1:1), in both the homogenized bulk and plastically deformed (ground) powder forms. The present study revealed a 2 /g phase transformations due to plastic deformation in the considered alloy compositions.…”

“…Instrumental parameters, like 2q correction, peakasymmetry, peak broadening parameters (U, V, W) [25,26] of a Si standard sample, assumed to have no size and strain broadening, have been used as fitting parameters in the software following the procedure indicated by Lutterotti et al [27] and reported elsewhere [14][15][16][17][18]22,23]. The crystallite size (D) and the microstrain (h3 2 i 1/2 ) values were evaluated using the Popa model [28] of anisotropic 'sizestrain' broadening.…”

Microstructure characterization of nanocrystalline Ni3C synthesized by high-energy ball milling

“…In addition to structural and microstructural characterizations, the Rietveld method is also one of the best tools for quantitative estimation of amorphous and crystalline phases present in a multiphase system and the method was successfully applied for the determination of quantitative phase abundances of the composite materials [20,21,[27][28][29]. In the present study the relative abundances of Ni, graphite and Ni 3 C phases have been made by the Rietveld method of analysis.…”

“…It is well established that the observed peak broadening in a cold-worked material appears due to small particle size and lattice strain and these broadening can better be approximated by the Lorentzian and Gaussian functions respectively. The pseudo-Voigt (pV) function being a linear combination of Lorentzian and Gaussian functions, is the most reliable peak-shape function and is being widely used in Rietveld structure refinement and WAMLPA software [22,[26][27][28][29][30][31][32][33][34][35]. In computer software (MARQ2) [32] for WAMLPA, the pV function and an exponential asymmetry function for profile fitting and instrumental broadening respectively and a fifth order polynomial for background fitting, has been adopted to perform overlapping peak separation, accurate estimation of the background and complete profile analysis.…”

Comparison of thermally induced and deformation induced martensite in Fe–29% Ni–2% Mn alloy

“…Although martensite formed by cooling effect in FeNiMn alloys have been extensively studied [14][15][16][17][18] in several early reports, martensite formed by deformation effect have been much less investigated in these alloys in the past [19]. Therefore, the purpose of the present study was the examination and comparasion of thermally induced and deformation induced martensite morphology and crystallography in different austenite grain sizes of Fe-29% Ni-2% Mn alloy by transmission electron microscope, about which no work has yet been reported for the related composition of alloy.…”