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Slow-cooled CF8M duplex stainless steel is used for critical parts of the primary coolant pipes of nuclear reactors. This steel can endure severe service conditions, but it tends to become more brittle upon very long-term aging (tens of years). Therefore, it is essential to understand its specific microstructure and temporal evolution. As revealed by electron backscatter diffraction (EBSD) analyses, the microstructure consists of millimetre-scale ferritic grains within which austenite lath packets have grown with preferred crystallographic orientations concerning the parent ferritic phase far from the ferrite grain boundaries. In these lath packets where the austenite phase is nucleated, the lath morphology and crystal orientation accommodate the two ferrite orientations. Globally, the Pitsch orientation relationship appears to display the best agreement with the experimental data compared with other classical relationships. The austenite lath packets are parallel plate-shaped laths, characterized by their normal n . A novel methodology is introduced to elucidate the expected relationship between n and the crystallographic orientation given the coarse interfaces, even though n is only partly known from the observation surface, in contrast to the 3D crystal orientations measured by EBSD. The distribution of retrieved normals n is shown to be concentrated over a set of discrete orientations. Assuming that the ferrite and austenite obey the Pitsch orientation relationship, the determined lath normals are close to an invariant direction of the parent phase given by the same orientation relationship., (© Maxime Mollens et al. 2024.)

Gymnolaemata bryozoans produce CaCO 3 skeletons of either calcite, aragonite, or both. Despite extensive research, their crystallography and biomineralization patterns remain unclear. We present a detailed study of the microstructures, mineralogy, and crystallography of eight extant cheilostome species using scanning electron microscopy, electron backscatter diffraction, atomic force microscopy, and micro-computed tomography. We distinguished five basic microstructures, three calcitic (tabular, irregularly platy, and granular), and two aragonitic (granular-platy and fibrous). The calcitic microstructures consist of crystal aggregates that transition from tabular or irregularly platy to granular assemblies. Fibrous aragonite consists of fibers arranged into spherulites. In all cases, the crystallographic textures are axial, and stronger in aragonite than in calcite, with the c-axis as the fiber axis. We reconstruct the biomineralization sequence in the different species by considering the distribution and morphology of the growth fronts of crystals and the location of the secretory epithelium. In bimineralic species, calcite formation always predates aragonite formation. In interior compound walls, growth proceeds from the cuticle toward the zooecium interior. We conclude that, with the exception of tabular calcite, biomineralization is remote and occurs within a relatively wide extrapallial space, which is consistent with the inorganic-like appearance of the microstructures. This biomineralization mode is rare among invertebrates., Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-024-00233-1., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© The Author(s) 2024.)

Sustainable TiC-Fe-based cermets have been fabricated by adopting an Additive Manufacturing route based on laser powder bed fusion technology (L-PBF). The objective is to produce crack-free cermet components by employing novel multiple laser scanning techniques with variations in laser process parameters. Electron backscatter diffraction analysis (EBSD) was used to study the microstructure and microtexture evolution with variations in laser process parameters. The investigation revealed that adjusting the preheating scan speed (PHS) and melting scan speed (MS) influenced the growth and nucleation of TiC phases. Lowering these speeds resulted in grain coarsening, while higher scan speeds led to grain refinement with larger sub-grain boundaries. Moreover, a high scanning speed increases the degree of dislocation density and internal stress in the fabricated cermet parts. Notably, it is revealed that decreasing the laser scan speed enhanced the proportion of high-angle grain boundaries in the cermet components, signifying an increase in material ductility., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Cathodoluminescence and electron backscatter diffraction have been applied to exactly the same grain boundaries (GBs) in a Cu(In,Ga)S 2 solar absorber in order to investigate the influence of microstructure on the radiative recombination behaviour at the GBs. Two different types of GB with different microstructure were analysed in detail: random high angle grain boundaries (RHAGBs) and Σ3 GBs. We found that the radiative recombination at all RHAGBs was inhibited to some extent, whereas at Σ3 GBs three different observations were made: unchanged, hindered, or promoted radiative recombination. These distinct behaviours may be linked to atomic-scale grain boundary structural differences. The majority of GBs also exhibited a small spectral shift of about ±10 meV relative to the local grain interior (GI) and a few of them showed spectral shifts of up to ±40 meV. Red and blue shifts were observed with roughly equal frequency., (Creative Commons Attribution license.)

Microstructure analysis via electron backscatter diffraction has become an indispensable tool in materials science and engineering. In order to interpret or predict the anisotropy in crystalline materials, the texture is assessed, e.g. via pole figure diagrams. To ensure a correct characterization, it is crucial to align the measured sample axes as closely as possible with the manufacturing process directions. However, deviations are inevitable due to sample preparation and manual measurement setup. Postprocessing is mostly done manually, which is tedious and operator-dependent. In this work, it is shown that the deviation can be calculated using the contour of the crystal orientations. This can also be utilized to define the axis symmetry of pole figure diagrams through an objective function, allowing for symmetric alignment by minimization. Experimental textures of extruded profiles and synthetically generated textures were used to demonstrate the general applicability of the method. It has proven to work excellently for deviations of up to 5∘, which are typical for careful manual sample preparation and mounting. While the performance of the algorithm is reduced with increasing misalignment, good results have also been obtained for deviations up to 15∘., Competing Interests: Conflict of Interest: An Austrian patent application (A 50565/2023) for the method has been filed by LKR Light Metals Technologies, a subsidiary of Austrian Institute of Technology., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Microscopy Society of America.)

Sub-micro dislocation cellular structures formed during rapid solidification break the strength-ductility trade-off in laser powder bed fusion (LPBF)-processed 316L stainless steel through high-density dislocations and segregated elements or precipitates at the cellular boundaries. The high-density dislocation entangled at the cellular boundary accommodates solidification strains among the cellular structures and cooling stresses through elastoplastic deformation. Columnar grains with cellular structures typically form along the direction of thermal flux. However, the ultra-low misorientations between the adjacent cellular structures and their interactions with the cellular boundary formation remain unclear. In this study, we revealed the ultra-low misorientations between the cellular structures in LPBF-processed 316L stainless steel using conventional electron backscatter diffraction (EBSD), transmission Kikuchi diffraction (TKD), and transmission electron microscopy (TEM). The conventional EBSD and TKD analysis results could provide misorientation angles smaller than 2°, while the resolution mainly depends on the specimen quality and scanning step size, and so on. A TEM technique with higher spatial resolution provides accurate information between adjacent dislocation cells with misorientation angles smaller than 1°. This study presents evidence that the TEM method is the better and more precise analytical method for the misorientation measurement of the cellular structures and provides insights into measuring the small misorientation angles between adjacent dislocation cells and nanograins in nanostructured metals and alloys with ultrafine-grained microstructures.

The rapid collection and indexing of electron diffraction patterns as produced via electron backscatter diffraction (EBSD) has enabled crystallographic orientation and structural determination, as well as additional property-determining strain and dislocation density information with increasing speed, resolution, and efficiency. Pattern indexing quality is reliant on the noise of the collected electron diffraction patterns, which is often convoluted by sample preparation and data collection parameters. EBSD acquisition is sensitive to many factors and thus can result in low confidence index (CI), poor image quality (IQ), and improper minimization of fit, which can result in noisy datasets and misrepresent the microstructure. In an attempt to enable both higher speed EBSD data collection and enable greater orientation fit accuracy with noisy datasets, an image denoising autoencoder was implemented to improve pattern quality. We show that EBSD data processed through the autoencoder results in a higher CI, IQ, and a more accurate degree of fit. In addition, using denoised datasets in HR-EBSD cross correlative strain analysis can result in reduced phantom strain from erroneous calculations due to the increased indexing accuracy and improved correspondence between collected and simulated patterns., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

We have previously shown that sharpening the cutting edge of a cemented carbide tool by chemical-mechanical polishing (CMP) improved the cutting speed by approximately 150% and reduced the wear on the flank surface by approximately 50% compared to a commercial tool when cutting a heat-resistant alloy. In addition, the cutting edges of carbide tools treated by laser doping (LD) using boron nitride as doping material achieved approximately 100 times longer cutting distance in glass machining than the edges of carbide tools treated with CMP grinding wheels. In this study, LD was conducted on a tool base material (WC-Co) to investigate and understand the crystal structure changes of the base material upon treatment. Electron backscatter diffraction and X-ray diffraction results show that the effect of LD was observed in the region 50 nm below the surface. LD improved the strength by approximately 11.7% without destroying the surface crystal structure. Thus, doping can be performed on tool tips while maintaining the WC structure to improve the performance of WC-Co cutting tools., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Commercial electron backscatter diffraction (EBSD) systems generally use interplanar angle matching for pattern indexing, and thus, they are unable to distinguish between some similar phases with close interplanar angles, such as Al and Si. The interplanar spacing is more diagnostic but generally difficult to apply in pattern indexing because it lacks precision. In this study, we proposed an efficient approach for accurately measuring interplanar spacing by correcting the reciprocal-lattice vector (RLV). The phase discrimination of Al and Si was performed by interplanar spacing matching. The Kikuchi bands were identified automatically by the self-developed method using pattern rotation combined with grey gradient recognition without the help of human eyes. The reliable RLV relationship was extracted by accurately drawing reciprocal-lattice vectors. The lengths of RLVs were corrected, and then the RLVs were used for evaluating lattice spacing. The results of five Kikuchi patterns with different clarity showed that this new method reduced the average error of interplanar spacings by 50.611% and achieved an average accuracy of 1.644% for lattice spacing calculation. The method could distinguish structures with a difference in lattice spacing of at least 3.3%. This method was also effective for fuzzy patterns and partially missing Kikuchi bands and might be used as a new strategy for improving the calculation accuracy of lattice spacing for fuzzy patterns. The method did not have additional requirements concerning the number of detected Kikuchi bands and poles. The accuracy of lattice spacing could be effectively improved by correcting the RLVs based on routine pattern recognition. This method might be used as an auxiliary approach to differentiate between similar phases and is well-adapted to the existing commercial EBSD system., (© 2023 Royal Microscopical Society.)

Measuring local chemistry of specific crystallographic features by atom probe tomography (APT) is facilitated by using transmission Kikuchi diffraction (TKD) to help position them sufficiently close to the apex of the needle-shaped specimen. However, possible structural damage associated to the energetic electrons used to perform TKD is rarely considered and is hence not well-understood. Here, in two case studies, we evidence damage in APT specimens from TKD mapping. First, we analyze a solid solution, metastable β-Ti-12Mo alloy, in which the Mo is expected to be homogenously distributed. Following TKD, APT reveals a planar segregation of Mo among other elements. Second, specimens were prepared near Σ3 twin boundaries in a high manganese twinning-induced plasticity steel, and subsequently charged with deuterium gas. Beyond a similar planar segregation, voids containing a high concentration of deuterium, i.e., bubbles, are detected in the specimen on which TKD was performed. Both examples showcase damage from TKD mapping leading to artefacts in the distribution of solutes. We propose that the structural damage is created by surface species, including H and C, subjected to recoil from incoming energetic electrons during mapping, thereby getting implanted and causing cascades of structural damage in the sample., Competing Interests: Conflict of Interest The authors declare that they have no competing interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Microscopy Society of America.)

Microtexture heterogeneities are commonly found in titanium forgings because of the thermomechanical processing. Also known as macrozones, these regions can reach millimetres in length, with grains sharing a similar crystallographic orientation leading to less resistance to crack propagation. Since the link between macrozones and the reduction of cold-dwell-fatigue performance on rotative components in gas turbine engines was established, efforts have been put into macrozone definition and characterization. The electron backscatter diffraction (EBSD) technique, widely used for texture analysis, allows for a qualitative macrozone characterization; however, further processing is required to define the boundaries and disorientation spread of each macrozone. Current approaches often use c -axis misorientation criteria, but this can sometimes lead to a large disorientation spread within a macrozone. This article describes the development and application of a computational tool implemented in MATLAB for automatic macrozone identification from EBSD data sets on the basis of a more conservative approach where both the c -axis tilting and rotation are considered. The tool allows for detection of macrozones according to the disorientation angle and density-fraction criteria. The clustering efficiency is validated by pole-figure plots, and the effects of the key parameters defining the macrozone clustering (disorientation and fraction) are discussed. In addition, this tool was successfully applied to both fully equiaxed and bimodal microstructures of titanium forgings., (© B. Fernández Silva et al. 2023.)

Electron backscatter diffraction (EBSD) generally links crystallographic orientation to the microstructure of crystalline materials. EBSD datasets are now commonly used to identify phases, grains, and their orientations using off-the-shelf software, although substantial additional information may be extracted. Due to the lack of commercially available software, advanced analyses are often done manually and provide only localised information, lacking statistical significance. Here we introduce novel automated methodologies for advanced analyses of microstructural features in Ni-based superalloys. Our methodologies provide additional insights into the characteristics of these features and their underlying physical phenomena. We showcase how to correct wrongly indexed γ/γ' interface artefacts in combined EBSD and energy-dispersive X-ray spectroscopy (EDS) measurements, how to classify recrystallised grains based on their location, how to assess and visualise grain boundary planes, and how to study the evolution of Σ3 twins during hot deformation. We further demonstrate how phase fractions and grain sizes are more accurately determined in combined EBSD-EDS measurements. The classification of recrystallised grains into different groups enables individual analyses, facilitating the straightforward identification of the underlying recrystallisation mechanism. Our grain boundary plane analysis provides insights into the coherence of Σ3 twins and the potential boundary planes of incoherent Σ3 boundaries. The current paper is a tutorial-style guide for these methodologies. The algorithms are made freely available and, although demonstrated here on Ni-based superalloys, can also be applied to other systems., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Plastic deformation is accumulated in slip bands in a wide variety of engineering alloys. Multiple material and loading conditions impact their distribution and degree of slip localization, but these effects are rarely quantified. To tackle this, the current work introduces a fast Fourier transform (FFT) decomposition method and applies it to a tensile-loaded polycrystalline nickel-based superalloy imaged via high-resolution digital image correlation and electron backscatter diffraction. This approach identifies active slip planes over the FFT images of individual grains and performs inverse transforms such that slip band traces with shared orientations are isolated. This technique enabled the largest quantification of slip band spacings and in-plane strains to date, with a total of 6,557 slip bands detected. The results show that the slip band spacings increase with grain size, with no evident dependence on grain orientation and Schmid factor. Slip bands are found to develop similar spacings along different octahedral planes and continue to spread over larger regions of the grain as the resolved shear stress of the active slip system increases. The FFT decomposition technique, which could be employed with multiple microscopy techniques, will allow for much-needed large-scale quantitative studies of slip localization., Competing Interests: Conflict of interest The authors declare none., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Microscopy Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The distribution of facet types affects the functionality of the surfaces of polycrystalline films. However, we are not aware of a previously published convenient method to determine their distribution. This work describes and demonstrates a process to determine and map the Miller indexes (hkl) of crystal facets exposed at the surfaces of polycrystalline films. To find facet types in non-trivial cases, one must know the orientation of the crystal and the direction in which the facet is facing. The method presented here combines the crystal orientations obtained with electron backscatter diffraction with the topography of the same sample area measured with atomic force microscopy. A challenging step is to transfer the data from the two instruments into a common coordinate system. The sequence of steps in the data processing is presented, with methods to verify the results. The process is illustrated with the analysis of an etched copper clad laminate (CCL) and an electroless Cu film deposited on the CCL. This example relates to facet selection in electroless and galvanic plating processes in printed circuit board production, where an uncontrolled transition from epitaxial to non-epitaxial growth can lead to surfaces with unacceptable roughness., (© 2023 The Authors. Journal of Microscopy published by John Wiley & Sons Ltd on behalf of Royal Microscopical Society.)

The macro- and microstructure, elemental composition, and crystallographic characteristics of the eggshell and eggshell membranes of the Crocodylus niloticus egg was investigated using optical and electron microscopy, energy-dispersive X-ray spectroscopy (EDS), electron backscatter diffraction (EBSD) and computerised tomography. The translucent ellipsoid egg is composed of two basic layers, the outer calcified layer referred to as the shell and an inner organic fibre layer, referred to as the shell membrane. The outer inorganic calcite shell is further divided into an external, palisade and mammillary layers with pore channels traversing the shell. The external layer is a thin layer of amorphous calcium and phosphorus, the underlying palisade layer consist of irregular wedge-shaped crystals composed calcite with traces of magnesium, sodium, sulphur and phosphorus. The crystals are mostly elongated, orientated perpendicular to the shell surface ending in cone-shaped knobs, which forms the inner mammillary layer. The elemental composition of the mammillae is like that of the palisade layer, but the crystal structure is much smaller and orientated randomly. The highest number of mammillae and shell pores are found at the equator of the egg, becoming fewer towards the egg poles. The shell thickness follows the same pattern, with the thickest area located at the equator. The eggshell membrane located right beneath and embedded in the mammillary layer of the shell; it is made up of unorganised fibre sheets roughly orientated at right angles to one another. Individual fibres consist of numerous smaller fibrils forming open channels that run longitudinally through the fibre., (© 2023 The Authors. Journal of Microscopy published by John Wiley & Sons Ltd on behalf of Royal Microscopical Society.)

A band width determination using the first derivative of the band profile systematically underestimates the true Bragg angle. Corrections are proposed to compensate for the resulting offset Δ a / a of the mean lattice parameters derived from as many Kikuchi band widths as possible. For dynamically simulated Kikuchi patterns, Δ a / a can reach up to 8% for phases with a high mean atomic number Z , whereas for much more common low- Z materials the offset decreases linearly. A predicted offset Δ a / a = f ( Z ) is therefore proposed, which also includes the unit-cell volume and thus takes into account the packing density of the scatterers in the material. Since Z is not always available for unknown phases, its substitution by Z max , i.e. the atomic number of the heaviest element in the compound, is still acceptable for an approximate correction. For simulated Kikuchi patterns the offset-corrected lattice parameter deviation is Δ a / a < 1.5%. The lattice parameter ratios, and the angles α, β and γ between the basis vectors, are not affected at all., (© Gert Nolze et al. 2023.)

The derivation of a crystal structure and its phase-specific parameters from a single wide-angle backscattered Kikuchi diffraction pattern requires reliable extraction of the Bragg angles. By means of the first derivative of the lattice profile, an attempt is made to determine fully automatically and reproducibly the band widths in simulated Kikuchi patterns. Even under such ideal conditions (projection centre, wavelength and lattice plane traces are perfectly known), this leads to a lattice parameter distribution whose mean shows a linear offset that correlates with the mean atomic number Z of the pattern-forming phase. The consideration of as many Kikuchi bands as possible reduces the errors that typically occur if only a single band is analysed. On the other hand, the width of the resulting distribution is such that higher image resolution of diffraction patterns, employing longer wavelengths to produce wider bands or the use of higher interference orders is less advantageous than commonly assumed., (© Gert Nolze et al. 2023.)

A pseudosymmetric description of the crystal lattice derived from a single wide-angle Kikuchi pattern can have several causes. The small size (<15%) of the sector covered by an electron backscatter diffraction pattern, the limited precision of the projection centre position and the Kikuchi band definition are crucial. Inherent pseudosymmetries of the crystal lattice and/or structure also pose a challenge in the analysis of Kikuchi patterns. To eliminate experimental errors as much as possible, simulated Kikuchi patterns of 350 phases have been analysed using the software CALM [Nolze et al. (2021). J. Appl. Cryst. 54 , 1012-1022] in order to estimate the frequency of and reasons for pseudosymmetric crystal lattice descriptions. Misinterpretations occur in particular when the atomic scattering factors of non-equivalent positions are too similar and reciprocal-lattice points are systematically missing. As an example, a pseudosymmetry prediction depending on the elements involved is discussed for binary AB compounds with B 1 and B 2 structure types. However, since this is impossible for more complicated phases, this approach cannot be directly applied to compounds of arbitrary composition and structure., (© Gert Nolze et al. 2023.)

The copper molten marks at a fire site provide important clues for determining the causes of fire. Four factors have been presented to quantitatively discriminate copper molten marks, namely the fraction of (001) component perpendicular to the demarcation line, the grain aspect ratio, the fraction of Σ3 boundaries, and the fraction of maximum grain size. However, only laboratory-level results of these parameters have been presented, and their applicability in actual fires is yet to be verified. In this study, a fire reproduction experimental system was configured to generate molten marks similar to those in actual fire sites. The molten marks were measured by electron backscatter diffraction and applied to the four discriminant factors. The results obtained similar characteristics to those of the laboratory unit, confirming the applicability of the four discriminant factors. Discriminant equations and processes that can distinguish the primary and secondary arc beads were derived using the molten marks generated in the laboratory and reproduction experiments. Furthermore, a probabilistic discrimination method and classification model developed by machine learning were proposed. Therefore, the use of the discriminants in actual fires can improve the reliability of the statistics and prevent the recurrence of similar fires.

A novel approach for the correlation of local martensite tetragonality determined by electron backscatter diffraction and carbon distribution by atom probe tomography (APT) is presented. The two methods are correlated by site-specific sample preparation for APT based on the local tetragonality. This approach is used to investigate the local carbon distribution in high carbon steel with varying local martensite tetragonality. Regions with low tetragonality show clear agglomeration of carbon based on statistical nearest neighbour (NN) analysis, while regions with high tetragonality show only small elongated agglomerations of carbon and no significant clustering using NN analysis. The APT average bulk carbon content shows no quantitative difference between regions with low and high tetragonality, indicating that no significant long-range diffusion of carbon has taken place.

Bragg coherent X-ray diffraction imaging (BCDI) allows the 3D measurement of lattice strain along the scattering vector for specific microcrystals. If at least three linearly independent reflections are measured, the 3D variation of the full lattice strain tensor within the microcrystal can be recovered. However, this requires knowledge of the crystal orientation, which is typically attained via estimates based on crystal geometry or synchrotron microbeam Laue diffraction measurements. Presented here is an alternative method to determine the crystal orientation for BCDI measurements using electron backscatter diffraction (EBSD) to align Fe-Ni and Co-Fe alloy microcrystals on three different substrates. The orientation matrix is calculated from EBSD Euler angles and compared with the orientation determined using microbeam Laue diffraction. The average angular mismatch between the orientation matrices is less than ∼6°, which is reasonable for the search for Bragg reflections. The use of an orientation matrix derived from EBSD is demonstrated to align and measure five reflections for a single Fe-Ni microcrystal via multi-reflection BCDI. Using this data set, a refined strain field computation based on the gradient of the complex exponential of the phase is developed. This approach is shown to increase accuracy, especially in the presence of dislocations. The results demonstrate the feasibility of using EBSD to pre-align BCDI samples and the application of more efficient approaches to determine the full lattice strain tensor with greater accuracy., (© David Yang et al. 2022.)

Electron backscatter diffraction (EBSD) has been used for more than 30 years for analyzing the structure of minerals and artificial substances. In recent times, EBSD has been widely applied for investigation of irradiated nuclear fuel and matrices for the immobilization of radioactive waste. The combination of EBSD and scanning electron microscopy (SEM/EDS) methods allows researchers to obtain simultaneously data on a specimen's local composition and structure. The article discusses the abilities of SEM/EDS and EBSD techniques to identify zirconolite polytype modifications and members of the polysomatic murataite-pyrochlore series in polyphase ceramic matrices, with simulations of Pu (Th) and the REE-actinide fraction (Nd) of high-level radioactive waste.

Crystallographic relationships between α- and β-phases resulting from phase transformations, which took place during the continuous water quenching (WQ), air cooling (AC) and furnace cooling (FC) of a Ti6Al4V plates solution treated at 1065 °C, were investigated by methods of electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). WQ, AC and FC resulted in typical martensite, basket-weave and parallel-plate Widmanstatten structures, respectively. The experimental distribution of α/β-misorientations deviated from BOR at set discrete angles close to 22, 30, 35 and 43°. The experimental spectra of angles were confirmed by theoretical calculations of the possible misorientations between the α and β phases through the β o →α→β II -transformation path based on Burgers orientation relationship (BOR). Joint analysis of the experimental data and theoretical calculations revealed that the secondary β II -phase was precipitated according to the sequence β o →α→β II during continuous cooling from the single-phase β-region. Similar spectra for α/β-phase misorientations for all investigated cooling rates acknowledged the similar transformation mechanisms and dominant shear component of the phase transformations.

Debye-Scherrer patterns, obtained from X-ray diffraction experiments using synchrotron light in transmission geometry, were analysed to construct generalized pole figures, and further used as input for an orientation distribution function inversion algorithm. By using Langford's method for separating strain and size contributions to peak broadening, it was possible, for the first time, to obtain full domain size and dislocation density generalized distribution functions (GDFs). This method was applied to cold-rolled and annealed interstitial-free steel. The predictions made using GDFs were corroborated by electron backscatter diffraction measurements and were also consistent with what was previously known for this kind of material under these conditions., (open access.)

With the lightening of the mobile devices, thinning of electrolytic copper foil, which is mainly used as an anode collection of lithium secondary batteries, is needed. As the copper foil becomes ultrathin, mechanical properties such as deterioration of elongation rate and tear phenomenon are occurring, which is closely related to microstructure. However, there is a problem that it is not easy to prepare and observe specimens in the analysis of the microstructure of ultrathin copper foil. In this study, electron backscatter diffraction (EBSD) specimens were fabricated using only mechanical polishing to analyze the microstructure of 8 μm thick electrolytic copper foil in plane view. In addition, EBSD maps and transmission electron microscopy (TEM) images were compared and analyzed to find the optimal cleanup technique for properly correcting errors in EBSD maps., (© 2022. The Author(s).)

Graphene films were grown by chemical vapor deposition on Cu foil. The obtained samples were characterized by Raman spectroscopy, ellipsometry, X-ray photoelectron spectroscopy and electron back-scatter diffraction. We discuss the time-dependent changes in the samples, estimate the thickness of emerging Cu 2 O beneath the graphene and check the orientation-dependent affinity to oxidation of distinct Cu grains, which also governs the manner in which the initial strong Cu-graphene coupling and strain in the graphene lattice is released. Effects of electropolishing on the quality and the Raman response of the grown graphene layers are studied by microtexture polarization analysis. The obtained data are compared with the Raman signal of graphene after transfer on glass substrate revealing the complex interaction of graphene with the Cu substrate.

The information of crystal structure and orientation can be provided by analysing the EBSD (electron backscatter diffraction) patterns which are obtained with the EBSD devices. The reliability and accuracy of the information relies on the location of bands and intersections of the EBSD patterns. In this study, a method is proposed to automatically obtain the locations and intersections of the EBSD patterns, that is, Kikuchi bands. The proposed method uses Radon transform and progressive probabilistic Hough transform to detect straight lines and line segments of the Kikuchi band edges, respectively. Then, Kikuchi bands can be presented by fitting the hyperbolas with the endpoints of line segments. The results can numerically describe the information of Kikuchi bands. Experimental results show that the method is robust and can detect more accurate Kikuchi bands and intersections., (© 2021 Royal Microscopical Society.)

Materials with an allotropic phase transformation can form microstructures where grains have orientation relationships determined by the transformation history. These microstructures influence the final material properties. In zirconium alloys, there is a solid-state body-centred cubic (b.c.c.) to hexagonal close-packed (h.c.p.) phase transformation, where the crystal orientations of the h.c.p. phase can be related to the parent b.c.c. structure via the Burgers orientation relationship (BOR). In the present work, a reconstruction code, developed for steels and which uses a Markov chain clustering algorithm to analyse electron backscatter diffraction maps, is adapted and applied to the h.c.p./b.c.c. BOR. This algorithm is released as open-source code (via github, as ParentBOR ). The algorithm enables new post-processing of the original and reconstructed data sets to analyse the variants of the h.c.p. α phase that are present and understand shared crystal planes and shared lattice directions within each parent β grain; it is anticipated that this will assist in understanding the transformation-related deformation properties of the final microstructure. Finally, the ParentBOR code is compared with recently released reconstruction codes implemented in MTEX to reveal differences and similarities in how the microstructure is described., (© Birch and Britton 2022.)

The data available in this article presents the microstructural information achieved via scanning electron microscopy and electron backscatter diffraction to evaluate the microstructure of maraging stainless steel 13Cr10Ni1.7Mo2Al0.4Mn0.4Si, in its as-built and heat-treated conditions, fabricated by laser powder bed fusion. In addition, the statistical analysis of the defects is included to indicate the quality of the additively manufactured metal. Furthermore, true stress-logarithmic strain diagrams of the material with different types of post-processing are available, indicating the strain hardening behavior of the material. These diagrams were achieved via quasi-static tensile tests performed in conjunction with the digital image correlation technique. Finally, the sample designs, additive manufacturing parameters, and the heat treatment procedure carried out on the material are also available in this paper to guide future research and ensure the repeatability of the data in this data article and its linked research paper. The research paper investigates the effects of processing and post-processing parameters on the microstructure, surface quality, residual stress, and mechanical properties of 13Cr10Ni1.7Mo2Al0.4Mn0.4Si (conventionally known as CX developed by EOS GmbH) processed by laser powder bed fusion [1]., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Author(s).)

Additive Friction Stir-Deposition (AFS-D) is a transformative, metallic additive manufacturing (AM) process capable of producing near-net shape components with a wide variety of material systems. The solid-state nature of the process permits many of these materials to be successfully deposited without the deleterious phase and thermally activated defects commonly observed in other metallic AM technologies. This work is the first to investigate the as-deposited microstructure and mechanical performance of a free-standing AA5083 deposition. An initial process parameterization was conducted to down-select optimal parameters for a large deposition to examine build direction properties. Microscopy revealed that constitutive particles were dispersed evenly throughout the matrix when compared to the rolled feedstock. Electron backscatter diffraction revealed a significant grain refinement from the inherent dynamic recrystallization from the AFS-D process. Tensile experiments determined a drop in yield strength, but an improvement in tensile strength in the longitudinal direction. However, a substantial reduction in tensile strength was observed in the build direction of the structure. Subsequent fractographic analysis revealed that the recommended lubrication applied to the feedstock rods, necessary for successful depositions via AFS-D, was ineffectively dispersed into the structure. As a result, lubrication contamination became entrapped at layer boundaries, preventing adequate bonding between layers.

3D electron backscatter diffraction (3D-EBSD) is a method of obtaining 3-dimensional crystallographic data through serial sectioning. The recent advancement of using a Xe + plasma focused ion beam for sectioning along with a complementary metal-oxide semiconductor based EBSD detector allows for an improvement in the trade-off between volume analyzed and spatial resolution over most other 3D characterization techniques. Recent publications from our team have focused on applying 3D-EBSD to understand microstructural phenomena in Ti-6Al-4V microstructures as a function of electron beam scanning strategies in electron beam powder bed fusion additive manufacturing. The microstructures resulting from this process have fine features, with α laths as small as 1 μm interwoven in a highly complex fashion, presenting a significant challenge to characterize. Over the course of these fundamental works, we have developed best-practice 3D-EBSD collection protocols and advanced methods for 3D data reconstruction and analysis of such microstructures which remain unpublished. These methods may be of interest to the 3D materials characterization community, especially considering the lack of standard commercial software tools. Thus, the current paper elaborates on the methods and analysis used to characterize fine titanium microstructures using 3D-EBSD and presents a detailed description of the new algorithms developed for probing the unique features therein. The new analyses include algorithms for identifying intervariant boundary types, classifying three-variant clusters, assigning grains to variants, and quantifying interconnectivity of branched α platelets., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

In this study, ultra-high-strength steels, namely, cold-hardened austenitic stainless steel AISI 301 and martensitic abrasion-resistant steel AR600, as base metals (BMs) were butt-welded using a disk laser to evaluate the microstructure, mechanical properties, and effect of post-weld heat treatment (PWHT) at 250 °C of the dissimilar joints. The welding processes were conducted at different energy inputs (EIs; 50-320 J/mm). The microstructural evolution of the fusion zones (FZ) in the welded joints was examined using electron backscattering diffraction (EBSD) and laser scanning confocal microscopy. The hardness profiles across the weldments and tensile properties of the as-welded joints and the corresponding PWHT joints were measured using a microhardness tester and universal material testing equipment. The EBSD results showed that the microstructures of the welded joints were relatively similar since the microstructure of the FZ was composed of a lath martensite matrix with a small fraction of austenite. The welded structure exhibited significantly higher microhardness at the lower EIs of 50 and 100 J/mm (640 HV). However, tempered martensite was promoted at the high EI of 320 J/mm, significantly reducing the hardness of the FZ to 520 HV. The mechanical tensile properties were considerably affected by the EI of the as-welded joints. Moreover, the PWHT enhanced the tensile properties by increasing the deformation capacity due to promoting the tempered martensite in the FZ.

We propose a scheme for assigning the martensite variant using electron backscatter diffraction in a martensite material that undergoes a solid-solid phase transformation. Based on the solutions of the crystallographic equations of martensite, we provide an algorithm to assign martensite variants to a particular microscopic region, and to check the elastic compatibility of the microstructure corresponding to low hysteresis and high reversibility in shape memory alloys. This article is part of the theme issue 'Topics in mathematical design of complex materials'.

Among NiTi-based alloys, one of the most promising and exploited alloys is NiTiCu, since the addition of Cu in substitution of Ni in the binary equiatomic NiTi has a significant influence on the martensitic transformation and the thermomechanical properties of the system. A high content of Cu improves the damping properties at the expense of phase homogeneity and workability. The present study focuses on an alloy with a high copper content, i.e., 20 at.%. For this specific composition, the correlation between the thermal treatments, microstructure, formation of secondary phases, and damping properties are investigated by several analyses. The microscopic observation, together with the compositional analysis, allowed the determination of four different phases in the alloy. Both the calorimetry and dynamic thermo mechanical measurements, which confirmed the high damping ability of the alloy, provided a characterization of the martensitic transition. Finally, the electron backscatter diffraction (EBSD) analysis detected the different crystallographic structures (i.e., cubic austenite, orthorhombic martensite, and cubic (face-centered) NiTi 2 ) and their orientation in the different phases. Therefore, the present work aims to improve the knowledge of the role of secondary phases in the optimization of the NiTiCu20 alloy as a valuable alternative to typical alloys used for damping purposes.

In this study, we conducted a quantitative evaluation of dislocation density by scanning electron microscopy electron channeling contrast imaging for α grains of a Ti-6Al-4V alloy deformed at room temperature. The depth of visibility of dislocations is experimentally measured as 140 to 160 nm by a serial sectioning observation. This result is compared with the theoretical value and applied to evaluate dislocation density. These factors confirm that the theoretically calculated value of the depth of visibility, at 5 to 6 times the extinction distance, is valid for the hexagonal close-packed Ti alloy., (© The Author(s) 2020. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

A new software is presented for the determination of crystal lattice parameters from the positions and widths of Kikuchi bands in a diffraction pattern. Starting with a single wide-angle Kikuchi pattern of arbitrary resolution and unknown phase, the traces of all visibly diffracting lattice planes are manually derived from four initial Kikuchi band traces via an intuitive graphical user interface. A single Kikuchi bandwidth is then used as reference to scale all reciprocal lattice point distances. Kikuchi band detection, via a filtered Funk transformation, and simultaneous display of the band intensity profile helps users to select band positions and widths. Bandwidths are calculated using the first derivative of the band profiles as excess-deficiency effects have minimal influence. From the reciprocal lattice, the metrics of possible Bravais lattice types are derived for all crystal systems. The measured lattice parameters achieve a precision of <1%, even for good quality Kikuchi diffraction patterns of 400 × 300 pixels. This band-edge detection approach has been validated on several hundred experimental diffraction patterns from phases of different symmetries and random orientations. It produces a systematic lattice parameter offset of up to ±4%, which appears to scale with the mean atomic number or the backscatter coefficient., (© Gert Nolze et al. 2021.)

Metal halide perovskite (MHP) solar cells have attracted worldwide research interest. Although it has been well established that grain, grain boundary, and grain facet affect MHPs optoelectronic properties, less is known about subgrain structures. Recently, MHP twin stripes, a subgrain feature, have stimulated extensive discussion due to the potential for both beneficial and detrimental effects of ferroelectricity on optoelectronic properties. Connecting the ferroic behavior of twin stripes in MHPs with crystal orientation will be a vital step to understand the ferroic nature and the effects of twin stripes. In this work, we studied the crystallographic orientation and ferroic properties of CH 3 NH 3 PbI 3 twin stripes, using electron backscatter diffraction (EBSD) and advanced piezoresponse force microscopy (PFM), respectively. Using EBSD, we discovered that the orientation relationship across the twin walls in CH 3 NH 3 PbI 3 is a 90° rotation about ⟨1̅1̅0⟩, with the ⟨030⟩ and ⟨111⟩ directions parallel to the direction normal to the surface. By careful inspection of CH 3 NH 3 PbI 3 PFM results including in-plane and out-of-plane PFM measurements, we demonstrate some nonferroelectric contributions to the PFM responses of this CH 3 NH 3 PbI 3 sample, suggesting that the PFM signal in this CH 3 NH 3 PbI 3 sample is affected by nonferroelectric and nonpiezoelectric forces. If there is piezoelectric response, it is below the detection sensitivity of our interferometric displacement sensor PFM (<0.615 pm/V). Overall, this work offers an integrated picture describing the crystallographic orientations and the origin of PFM signal of MHPs twin stripes, which is critical to understanding the ferroicity in MHPs.

Ni-based filler metal and Ni-Cu-based filler metal were used to obtain copper/stainless steel (Cu/SS) joints through wire-feeding laser welding. Along the SS/weld interface, there exist different grain sizes (from coarse columnar grains to fine equiaxed grains). The heat affected zone (HAZ) on the copper side consisted of two areas with different grain sizes and the size of the grain in the Cu-HAZ of the Ni-Cu-based filled joint was much smaller than that of the Ni-based filled joint. Our results showed that grain refinement at the copper/weld (Cu/weld) interface of the Ni-Cu-based filled joint was observed through high-resolution electron backscattered diffraction (EBSD). There was a hardness elevation at the Cu/weld interface of the Ni-Cu-based filled joint due to the grain refinement on the weld of the copper side. The maximum tensile strength of the Ni-Cu-based filled joint was obtained and reached 91.2% of the tensile strength of the copper base metal (Cu-BM). Joints in this study were observed to fracture in a ductile mode. Furthermore, the Ni-Cu-based filled joint exhibited a higher plastic deformation, which was primarily caused by the large deformation of the weld zone and the large deformation of the Cu-BM due to the high plasticity of the weld, which alleviated the stress concentration, as indicated by 2D-digital image correlation (DIC) test results.

The surfaces of textured polycrystalline N-type bismuth telluride and P-type antimony telluride materials were investigated using ex situ photoelectron emission microscopy (PEEM). PEEM enabled imaging of the work function for different oxidation times due to exposure to air across sample surfaces. The spatially averaged work function was also tracked as a function of air exposure time. N-type bismuth telluride showed an increase in the work function around grain boundaries relative to grain interiors during the early stages of air exposure-driven oxidation. At longer time exposure to air, the surface became homogenous after a ∼5 nm-thick oxide formed. X-ray photoemission spectroscopy was used to correlate changes in PEEM imaging in real space and work function evolution to the progressive growth of an oxide layer. The observed work function contrast is consistent with the pinning of electronic surface states due to the defects at a grain boundary.

The performance of metal-air batteries and fuel cells depends on the speed and efficiency of electrochemical oxygen reduction reactions at the cathode, which can be improved by engineering the atomic arrangement of cathode catalysts. It is, however, difficult to improve upon the performance of platinum nanoparticles in alkaline electrolytes with low-loading catalysts that can be manufactured at scale. Here, the authors synthesized nanoporous gold catalysts with increased (100) surface facets using electrochemical dealloying in sodium citrate surfactant electrolytes. These modified nanoporous gold catalysts achieved an 8% higher operating voltage and 30% greater power density in aluminum-air batteries over traditionally prepared nanoporous gold, and their performance was superior to commercial platinum nanoparticle electrodes at a 10 times lower mass loading. The authors used rotation disc electrode studies, backscattering of electrons, and underpotential deposition to show that the increased (100) facets improved the catalytic activity of citrate dealloyed nanoporous gold compared to conventional nanoporous gold. The citrate dealloyed samples also had the highest stability and least concentration of steps and kinks. The developed synthesis and characterization techniques will enable the design and synthesis of metal nanostructured catalysts with controlled facets for low-cost and mass production of metal-air battery cathodes.

The angular precision of crystal orientation determination by cross-correlating dynamically simulated electron diffraction patterns with experimental patterns via spherical harmonic analysis is investigated. The best precision found in this study is 0.016°, which approaches the level reported in the literature for other high-precision electron backscatter diffraction implementations. At this angular precision, the noise floor for geometrically necessary dislocation density calculations is found to be approximately 5×10 13 m -2 at a 200 nm step size. Conventional Hough-transform indexing of the same raw patterns gave an angular precision of 0.156° and a dislocation noise floor of 6×10 14 m -2 , an order of magnitude larger for both parameters, albeit better than is typical for Hough indexing due to the high-quality patterns used. Experimental trade-off curves of precision versus exposure time, pattern resolution (i.e. camera binning), and analysis bandwidth are also presented, allowing for optimization of data collection and analysis rates once the desired level of precision has been determined., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Metastable single crystals of nonstoichiometric Pb 1- x Te are obtained by rapid cooling from the melt. The composition and crystallographic morphology are studied using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electron backscatter diffraction. Most single crystals have cubic, pyramidal, or hemispherical shapes with sizes ranging from 50 to 400 μm. All crystals adopt the same face-centered cubic rock salt structure, and the crystal growth direction is ⟨100⟩. The bulk part of the rapidly cooled material solidifies in the form of a Te-rich polycrystalline material in which grains are separated by the PbTe-Te eutectic phase. The stabilization of nonstoichiometric Pb 1- x Te provides further scope for the optimization of lead telluride-based thermoelectric materials.

Iron-based Fe-Mn-Al-Ni shape-memory alloys are of rather low materials cost and show remarkable pseudoelastic properties. To further understand the martensitic transformation giving rise to the pseudoelastic properties, different Fe-Mn-Al-Ni alloys have been heat treated at 1473 K and quenched in ice water. The martensite, which is formed from a body-centred cubic austenite, is commonly described as face-centered cubic (f.c.c.), even though there are also more complex, polytypical descriptions of martensite. The presently studied backscatter Kikuchi diffraction (BKD) patterns have been evaluated, showing a structure more complex than simple f.c.c. This structure can be described by nanoscale twins, diffracting simultaneously in the exciting volume. The twinned structure shows a tetragonal distortion, not uncommon for martensite in spite of the lack of interstitial elements. These features are evaluated by comparing the measured BKD patterns with dynamically simulated ones., (© Peter D. B. Fischer et al. 2021.)

Two of the microstructural parameters most influential in the properties of polycrystalline materials are grain size and crystallographic texture. Although both properties have been extensively studied and there are a wide range of analysis tools available, they are generally considered independently, without taking into account the possible correlations between them. However, there are reasons to assume that grain size and orientation are correlated microstructural state variables, as they are the result of single microstructural formation mechanisms occurring during material processing. In this work, the grain size distribution and orientation distribution functions are combined in a single multivariate grain size orientation distribution function (GSODF). In addition to the derivation of the function, several examples of practical applications to low carbon steels are presented, in which it is shown how the GSODF can be used in the analysis of 2D and 3D electron backscatter diffraction data, as well as in the generation of representative volume elements for full-field models and as input in simulations using mean-field methods., (© Galán López and Kestens 2021.)

The microstructure and texture evolution of Ni-5 at%W (Ni5W) alloy substrates were investigated by in situ tensile testing along the rolling direction (RD), transverse direction (TD), and at 45° to the RD (45°-RD), as well as by electron backscatter diffraction characterization. The tensile stress direction had a significant influence on the texture evolution. The cubic texture in the Ni-5 at%W alloy exhibited severe degradation when the tensile angle was 45°-RD. In contrast, the cubic texture was relatively stable under high deformation along the RD or TD. It was found that the slip line system in the 45°-RD specimen was the key to the contrasting behavior. The effect of the tensile testing angle on the cubic texture evolution for Ni–W substrates was investigated, and the corresponding effect on the superconducting properties of coated materials was studied.

It is well known that changes in the starting powder can have a significant impact on the laser powder bed fusion process and subsequent part performance. Relationships between the powder particle size distribution and powder performance such as flowability and spreadability are generally known; however, links to part performance are not fully established. This study attempts to more precisely isolate the effect of particle size by using three customized batches of 17-4 PH stainless steel powders with small shifts in particle size distributions having non-intersecting cumulative size distributions, designated as Fine, Medium, and Coarse. It is found that the Fine powder has the worst overall powder performance with poor flow and raking during spreading while the Coarse powder has the best overall flow. Despite these differences in powder performance, the microstructures (i.e., porosity, grain size, phase, and crystallographic texture) of the built parts using the same process parameters are largely the same. Furthermore, the Medium powder produced parts with the highest mechanical properties (i.e., hardness and tensile strength) while the Fine and Coarse powders produced parts with effectively identical mechanical properties. Parts with good static mechanical properties can be produced from powders with a wide range of powder performance.

Investigations by electron backscatter diffraction (EBSD) and X-ray diffraction with the use of synchrotron radiation, as well as parallel extended finite element (XFEM) simulations, reveal the evolution of the 316L stainless steel microstructure in the vicinity of a macro-crack developing at the temperature of liquid helium (4.2 K). The fracture propagation induces a dynamic, highly localized phase transformation of face-centred cubic austenite into α' martensite with a body-centred cubic structure. Synchrotron studies show that the texture of the primary phase controls the transition process. The austenite grains, tending to the stable Brass orientation, generate three mechanisms of the phase transformation. EBSD studies reveal that the secondary phase particles match the ordered austenitic matrix. Hence, interphase boundaries with the Pitsch disorientation are most often formed and α' martensite undergoes intensive twinning. The XFEM simulations, based on the experimentally determined kinetics of the phase transformation and on the relevant constitutive relationships, reveal that the macro-crack propagates mainly in the martensitic phase. Synchrotron and EBSD studies confirm the almost 100% content of the secondary phase at the fracture surface. Moreover, they indicate that the boundaries formed then are largely random. As a result, the primary beneficial role of martensite as reinforcing particles is eliminated.

Although electron backscatter diffraction (EBSD) analysis for Mg-Li based alloys is difficult to conduct, this technique is necessary to understand the properties of these alloys. Numerous studies have addressed the use of electron backscatter diffraction (EBSD) analysis as an effective technique for quantifying Mg-Li based alloys. However, a crystallographic orientation determination of β-Mg by EBSD has not been achieved thus far. In this study, to conduct EBSD analysis of the body-centered cubic (BCC) phase in Mg-Li based alloys with various applied equivalent strains prepared by severe plastic deformation, surface treatment techniques were established. By the use of both Ar + ion milling and Ar + ion etching under ultra-high vacuum conditions, the Kikuchi patterns of Mg-Li based alloys were detected. According to the results of the EBSD analysis, it was concluded that the structural evolution of BCC Mg-Li based alloys can be understood with this approach. From the results of the EBSD analysis, it is clarified that the high strength of this alloy is attributed to the combination of Hall-Petch relationship and Bailey-Hirsch relationship., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The electronic Seebeck response in a conductor involves the energy-dependent mean free path of the charge carriers and is affected by crystal structure, scattering from boundaries and defects, and strain. Previous photothermoelectric (PTE) studies have suggested that the thermoelectric properties of polycrystalline metal nanowires are related to grain structure, although direct evidence linking crystal microstructure to the PTE response is difficult to elucidate. Here, we show that room temperature scanning PTE measurements are sensitive probes that can detect subtle changes in the local Seebeck coefficient of gold tied to the underlying defects and strain that mediate crystal deformation. This connection is revealed through a combination of scanning PTE and electron microscopy measurements of single-crystal and bicrystal gold microscale devices. Unexpectedly, the photovoltage maps strongly correlate with gradually varying crystallographic misorientations detected by electron backscatter diffraction. The effects of individual grain boundaries and differing grain orientations on the PTE signal are minimal. This scanning PTE technique shows promise for identifying minor structural distortions in nanoscale materials and devices., Competing Interests: The authors declare no competing interest.

For the precise determination of orientations in polycrystalline materials, electron backscatter diffraction (EBSD) requires a consistent calibration of the diffraction geometry in the scanning electron microscope (SEM). In the present paper, the variation of the projection center for the Kikuchi diffraction patterns which are measured by EBSD is calibrated using a projective transformation model for the SEM beam scan positions on the sample. Based on a full pattern matching approach between simulated and experimental Kikuchi patterns, individual projection center estimates are determined on a subgrid of the EBSD map, from which least-square fits to affine and projective transformations can be obtained. Reference measurements on single-crystalline silicon are used to quantify the orientation errors which result from different calibration models for the variation of the projection center.