Fig. 3: Neutron diffraction and TEM experiments showing the dominance of edge dislocations in CrMoNbV.

a Neutron-diffraction patterns presenting interplanar spacings with peaks indexed for the BCC structure of CrMoNbV, at temperatures of 293 and 1173 K. b Axial and transverse lattice strains versus applied load, shown as the applied stress versus lattice strain so that the slopes correspond to the planar Young’s moduli \(({E}_{hkl})\) and Young’s moduli/Poisson’s ratios \(({E}_{hkl}/{\nu }_{hkl})\), as indicated for the {110}, {200}, {211}, and {310} planes, respectively, at T = 293 K. The onset of plastic yielding (yield stress) is presented as the dashed line. c Evolution of q parameters as a function of plastic strain, which is obtained from the Convolutional Multiple Whole Profile (CMWP) fitting. Dashed lines indicate values of q parameters for edge and screw character dislocations, considering a 15% error margin for the elastic constants. The error bars in the q-parameter values are determined by the fractions of edge or screw dislocations. d Modified-Williamson-Hall plot, FWHM versus \(K{C}^{0.5}\) at plastic strains of 0.8%, 4.2%, and 5.3%, respectively, at T = 293 K. The plots were obtained from the physical profiles calculated by the CMWP procedure, considering free of the instrumental effects on the FWHM data. The pattern of the undeformed specimen was applied to the CMWP procedure as an instrumental pattern. The much better agreement of the data with the edge analysis demonstrates the dominance of edge dislocations. e Annular-Bright-field (ABF)-STEM image of CrMoNbV at a plastic strain of 4.2% with a two-beam condition near \(Z=[\bar{1}01]\) and \(\overrightarrow{g}=(101)\). All straight dislocation lines longer than 5 nm are highlighted by blue and red lines, corresponding to their identifications as edge and screw dislocations, respectively. f Stereographic projection related to the [\(\bar{1}01\)] orientation, where [\(101\)] has been aligned with images in (e). All possible dislocations are indicated, and those corresponding to the images in (e) are highlighted in bold. The degrees indicate the angles with respect to the [\(101\)] direction. Blue lines/blue symbols present those dislocations identified as edge, and red lines/symbols indicate those dislocations identified as screw. The green lines/symbols represented the dislocations that could be either edge or screw, which was excluded in the ratio calculation. As a result, ~55% of the dislocations are identified as edge.