Reversal of asymmetry of X-ray peak profiles from individual grains during a strain path change

Impact of thickness variation on structural, dielectric and piezoelectric properties of (Ba,Ca)(Ti,Zr)O3 epitaxial thin films

“…The shift in the profile’s asymmetry included in Fig. S2, was quantified by the parameter κ = 2θ max − θ mean , were 2θ max and θ mean are the Bragg-angles of the maximum and the mean of the profile, respectively 24 . Chen et al .…”

High-Resolution Single-Grain Diffraction of Polycrystalline Materials

“…This difference in elastic strain of the subgrains is reflected in the radial profile obtained before the strain path change in Figure 4(a) which is less broad and has its tail at higher diffraction angles. With increasing tensile strain after the strain path change, the asymmetry of the radial profile becomes reversed, due to the subgrains developing compressive elastic strains instead of the tensile elastic strains from the pre-deformation [37,43]. This highlights, how reorganization of deformation structures in individual grains in polycrystalline specimens and details about individual subgrains can be revealed in-situ by high resolution reciprocal space mapping during a change in loading conditions, e.g.…”

“…As an example, the particular case where the new tensile direction is orthogonal to the tensile axis of the pre-deformation is discussed [43,40]. Dog-bone shaped specimens were cut from coarse-grained copper sheets pre-deformed by 5% in uniaxial tension such that the new tensile axis is perpendicular to the tensile direction of the pre-deformation.…”

In Situ Observation of the Dislocation Structure Evolution During a Strain Path Change in Copper

“…9 includes also the asymmetries observed for grains from specimens experiencing a change in the tensile direction by 90°. 29 In this case, the chosen diffraction vector close to the tensile direction of the in situ deformation is perpendicular to the tensile direction of the predeformation. Due to the Poisson effect, compressive stresses of subgrains along the original tensile direction will cause tensile elastic strains along the diffraction vector (side case, e 90 ¼ Àme jj ) and, hence, a negative asymmetry.…”

“…Due to the Poisson effect, compressive stresses of subgrains along the original tensile direction will cause tensile elastic strains along the diffraction vector (side case, e 90 ¼ Àme jj ) and, hence, a negative asymmetry. 29 When loading along the new tensile direction, back stresses along the new loading direction develop in the subgrains, leading to compressive strains along the new tensile direction and a reversal of the asymmetry.…”