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A key challenge for solid‐state batteries is the fabrication of high‐capacity cathodes with high area loading and good rate performance. To reliably quantify the performance of high‐capacity cathodes, electrochemically stable, and high‐rate counter electrodes are essential. Otherwise, a three‐electrode setup is required. In–Li alloy electrodes are used for years in a kind of standard approach, since these seem to offer stable operation. In this comparative study, seven preparation methods for In–Li electrodes are examined, determining their suitability for cathode testing. The microstructure of a planar (i.e., foil) and a particle‐based (i.e., composite) anode configuration is analyzed in more detail. Their rate‐dependent electrode performance as well as electrochemical and chemomechanical reversibility in full‐cell configuration are analyzed. The combined results demonstrate the limitations of In–Li electrodes for high‐capacity testing, especially at high rates, while confirming their suitability for simple lab‐scale testing. Preparation significantly influences the electrode microstructure and kinetics, consequently impacting the performance benchmarks of cathodes. These findings underscore both the challenges involved in applying In–Li counter electrodes and the resulting limited comparability of results from different laboratories. [ABSTRACT FROM AUTHOR]

The hydrogen embrittlement behavior of a prerolled Fe–15Mn–0.65C–2Al–2Si high‐Mn steel with various cut‐edge properties is studied via hydrogen precharging and slow strain rate test. In the presence of hydrogen, samples prepared by laser cutting under atmosphere of N2 exhibit the best total elongation at about 39%. Press blanking produces severe shear deformation, tensile residual stresses, and strain‐induced martensite, resulting in a high risk to hydrogen‐induced cracking. With compressive residual stresses produced from waterjet, corresponding samples exhibit the lowest elongation loss against hydrogen. Despite hydrogen charging, the fracture surfaces show transgranular quasi‐cleavage features, for which mechanical twinning from prerolling plays a critical role. The hydrogen‐enhanced decohesion mechanism accounts for cleavage fracture since hydrogen segregation reduces cohesive stress at twin boundaries. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Disentangling nucleation and growth in materials that crystallize on the nanosecond time scale is experimentally quite challenging since the relevant processes also take place on very small, i.e., sub‐micrometer length scales. Phase change materials are bad glass formers, which often crystallize rapidly. Here systematic changes in crystallization kinetics are shown in pseudo‐binary compounds of GeTe and Sb2Te3 and related solids subjected to short laser pulses. Upon systematic changes in stoichiometry, the speed of crystallization changes by three orders of magnitude concomitantly with pronounced changes in stochasticity. Resolving individual grains with electron backscatter diffraction (EBSD) permits to disentangle of the process of nucleation and growth. From these experiments, supported by multiphysics simulations of crystallization, it can be concluded that high crystallization speeds with small stochasticity characterize phase change materials with fast nucleation, while compounds that nucleate slowly crystallize much more stochastically. [ABSTRACT FROM AUTHOR]

The synthesis of a strontium hexaferrite magnet is studied using in situ synchrotron powder X‐ray diffraction (PXRD) with a 16‐ms time resolution. The precursor material is cold compacted shape‐controlled goethite and strontium carbonate. The time evolution of the phases is modeled with sequential Rietveld refinements revealing that strontium hexaferrite forms within seconds at ≈1173 K. Texture analysis is performed on selected PXRD frames throughout the experiment, and the preferred orientation introduced by cold‐pressing goethite prevails through the iron oxide phase transitions (goethite → hematite → strontium hexaferrite). Electron backscatter diffraction (EBSD) data on the final pellet confirms the preferred orientation observed with PXRD. The resulting magnet has respectable magnetic properties, considering the simplicity of the preparation method, with an energy product (BHmax) of 18.6(8) kJ m−3. [ABSTRACT FROM AUTHOR]

Scanning electron microscopy‐based high‐resolution digital image correlation (HRDIC) is now an established technique, providing full‐field strain and displacement measurement at the microscale. Techniques for generating speckle patterns for sub‐micron strain mapping can often be either substrate dependent or rely on applying aggressive conditions which may alter the microstructure of interest or damage the substrate in highly sensitive materials. We detail a modification of a methodology successfully applied in the literature to allow its use with metallic materials that are particularly sensitive to the corrosive media, such as copper‐base alloys. Nanometre‐thick silver films, applied with physical vapour deposition, are remodelled using NaBr in non‐aqueous isopropanol, replacing the aqueous solution of NaCl in the original method, forming a uniform dispersion of silver islands highly suitable for digital image correlation (DIC) measurement. The entire procedure is performed at ambient temperature. We find that the DIC pattern is suitably electron transparent to allow electron backscatter diffraction (EBSD) measurements without pattern removal, producing diffraction patterns of sufficient quality for cross‐correlation based high‐angular resolution EBSD. This property facilitates simultaneous EBSD and DIC mapping experiments, providing deeper insights into the kinematics of plastic deformation in crystalline materials. Sub‐100 nm islands are achieved through control of the sputter coating parameters, resulting in DIC cross‐correlation subwindows of 140 nm with a 50% overlap. This resolution is sufficient to capture the fine detail of strain localisation phenomena during plastic deformation, demonstrated here with a case study in CuCrZr, a precipitation‐hardened heat sink material for application in nuclear fusion components. Here, we extract full‐field displacement data with DIC and corresponding orientation information using EBSD without the need for pattern removal. [ABSTRACT FROM AUTHOR]

To measure textures of hot rolled martensitic and bainitic steels, electron backscatter diffraction (EBSD) is applied to large areas, each covering about a thousand of prior grains. A scanning step is selected to keep reasonable time of the data acquisition still providing in any grain a significant number of analyzed points. Contributions to the transformation texture appearing from deformation and recrystallization components of the parent texture are estimated with the Bain relationship. To assess the parent austenite state, their proportion is then expressed by a scalar parameter. The results are verified by independent metallographic data. Avoiding the reconstruction of prior grains, this statistical approach will facilitate evaluation of complex austenite structures with comparable fractions of dissimilar material states. [ABSTRACT FROM AUTHOR]

To achieve the desired microstructural properties, the ongoing development and innovation in new structural steels require novel thermal processing. This study aims to improve the mechanical properties of a commercial spring carbon–silicon steel by tailoring its microstructure through a process involving quenching and partitioning (Q&P) followed by bainitic transformation. A two‐stage Q&P process is proposed to generate a nanoscale dispersion of stable retained austenite and carbides within the tempered martensite and bainite microstructure. The resulting tensile properties demonstrate a yield strength of 1280 MPa, an ultimate tensile strength of 1875 MPa, and a total elongation of 8.03%. These values surpass those of conventional spring 9254 steel, highlighting the effectiveness of the thermal treatment design. Microstructure analysis reveals the presence of tempered martensite, bainite sheaves, nanoscale carbides, and aggregates of retained austenite. Moreover, the resulting body‐centered cubic matrix exhibits minimal lattice tetragonality of ≈1.0051, coupled with stable retained austenite featuring a carbon concentration of ≈3.42 ± 0.5 wt%, resulting in outstanding strength–ductility properties. These findings indicate that the proposed two‐stage Q&P process, followed by bainitic transformation, significantly enhances the mechanical properties of carbon–silicon steels, making it a promising candidate for high‐performance spring applications. [ABSTRACT FROM AUTHOR]

The crystal structure and transformation path from austenite to 10M martensite in Ni–Mn–Ga single crystal are examined employing high‐energy synchrotron radiation, scanning, and transmission electron microscopy. Using temperature gradient, an austenite/twinned martensite interface is stabilized revealing the crystal structure and microstructure of both phases and the transformation sequence across the interface. Depending on the distance from the interface, three distinct types of martensite crystal lattice, namely simple tetragonal and two monoclinic modulated ones, that is, 10M′ and 10M are confirmed. In situ measurements show that lattice mismatch formed at the habit plane is compensated by the formation of micro‐twinned and branched martensite along with an elastic change in lattice parameters. It is shown that the characteristics for periodic shuffling twin boundaries, such as modulation twins or inverted stacking faults, are installed in later stages of transformation. In other words, large microstructure elements that most efficiently accommodate the strain are installed first, and then smaller elements are operable. Overall, the experimental results show that the crystal lattice does not adapt modulated phase at the habit plane and cannot be built up from simple non‐modulated tetragonal blocks but rather a specific sequence of phase transformations using shear/shuffling deformation takes place. [ABSTRACT FROM AUTHOR]

The aluminium based matrix composites have excellent mechanical properties to use in automobile, aerospace, aviation, and military industries. The aluminium based matrix composite possesses desired characteristics like specific strength, excellent rigidity and wear resistance. The stir casting technique was used to fabricate the nanocomposite of AA6063 alloy reinforced with 5 weight % nano aluminium oxide particulate. To improve the microhardness of as cast and aluminium based nanocomposites, multiaxial forging was performed up to three passes for grain refinement. Wire electrical discharge machining was used to machine both as cast and "AA6063/Al2O3" (zero and three multi axial forging pass). The machining characteristics of samples were statistically examined using the Taguchi technique. The material removal rate in three multiaxial forging pass nanocomposite sample increased as peak current increases. However, increasing the pulse off time resulted in the lowest material removal rate. The surface roughness was found to be higher in the nanocomposite sample in comparison to as cast. The machining on nanocomposite multiaxial forged sample has a greater impact as compared to as cast. After machining, scanning electron microscopy was used to examine the surface morphology. The presence of different elements in the castings was validated using energy dispersive X‐ray spectroscopy. [ABSTRACT FROM AUTHOR]

Seismic anisotropy constitutes a useful tool for imaging the structure along the plate interface in subduction zones, but the seismic properties of mafic blueschists, a common rock type in subduction zones, remain poorly constrained. We applied the technique of electron backscatter diffraction (EBSD) based petrofabric analysis to calculate the seismic anisotropies of 14 naturally deformed mafic blueschists at dry, ambient conditions. The ductilely deformed blueschists were collected from terranes with inferred peak P‐T conditions applicable to subducting slabs at or near the plate interface in active subduction zones. Epidote blueschists display the greatest P wave anisotropy range (AVp ∼7%–20%), while lawsonite blueschist AVp ranges from ∼2% to 10%. S wave anisotropies generate shear wave splitting delay times up to ∼0.1 s over a thickness of 5 km. AVp magnitude increases with glaucophane abundance (from areal EBSD measurements), decreases with increasing epidote or lawsonite abundance, and is enhanced by glaucophane crystallographic preferred orientation (CPO) strength. Two‐phase rock recipe models provide further evidence of the primary role of glaucophane, epidote, and lawsonite in generating blueschist seismic anisotropy. The symmetry of P wave velocity patterns reflects the deformation‐induced CPO type in glaucophane—an effect previously observed for hornblende on amphibolite P wave anisotropy. The distinctive seismic properties that distinguish blueschist from other subduction zone rock types and the strong correlation between anisotropy magnitude/symmetry and glaucophane CPO suggest that seismic anisotropy may be a useful tool in mapping the extent and deformation of blueschists along the interface, and the blueschist‐eclogite transition in active subduction zones. Plain Language Summary: The directional dependence of seismic wave speeds in the subsurface, or seismic anisotropy, can allow us to map the Earth's structure in subduction zones. To improve the interpretation of seismic data collected in active subduction zones, we characterized the range of seismic anisotropy created by blueschists (a common subduction zone rock‐type) that were returned to the surface after being deformed in ancient subduction margins. We calculate the anisotropy of each blueschist rock from mineral orientations collected in the lab combined with the elastic properties of these minerals. Trends in seismic anisotropy were compared to the changes in composition and preferred orientations of minerals (produced by deformation). We found that blueschists can generate a broad range of seismic anisotropy, and that this anisotropy is enhanced by increasing amounts of the mineral glaucophane. The seismic anisotropy is further increased when the glaucophane minerals are more uniformly oriented, as is typical in rocks that have experienced higher levels of deformation. The seismic anisotropy and seismic wave speeds of blueschists are distinctive from those of other common subduction zone rocks. Therefore, these results suggest blueschist seismic anisotropy can be used to improve our ability to map structure and deformation occurring in active subduction zones. Key Points: Calculated blueschist Vp anisotropy up to ∼20% with a plateau at ∼10%, with lineation‐parallel fast axis and foliation‐normal slow axisThe anisotropy magnitude increases with glaucophane modal abundance/crystallographic preferred orientation (CPO) strength and is diluted by epidote/lawsonite abundanceThe glaucophane CPO type correlates with the Vp pattern and increasing AVp magnitude in mafic blueschists [ABSTRACT FROM AUTHOR]

High‐strength low‐alloy (HSLA) steels are widely used to their excellent mechanical properties. Despite this, the precipitation process occurring during annealing after cold rolling has not been extensively studied. Herein, the precipitation of niobium carbide (NbC) is examined during both hot‐rolling and annealing processes. Field emission transmission electron microscopy and inductively coupled plasma optical emission spectroscopy are employed for the analyses, with a particular focus on using the residual electrochemical extraction method for quantification. The NbC precipitates formed during hot rolling and annealing are individually assessed. The findings indicate that new NbC precipitates form during annealing process after cold rolling, and these precipitates are smaller than those formed during hot rolling. This study offers valuable insights into the precipitation process of NbC in cold‐rolled HSLA steel and has implications for the development of improved steel processing techniques. [ABSTRACT FROM AUTHOR]

Recent advancements have shown great promise in utilizing wire‐fed direct energy deposition (DED) for building aluminum alloy structures. However, utilizing the wire‐fed DED approach for fabricating metal matrix composite structures remains a significant challenge. Herein, a wire‐based additive manufacturing process is used to successfully produce a 1D boron nitride nanotube (BNNT)‐reinforced aluminum composite with high strength. Al‐BNNT electrode is developed in house. The microstructural changes that occur during layer‐by‐layer deposition are investigated. The grain morphology changes from equiaxed grains in the bottom layer to columnar grains in the top layer. BNNTs act as nuclei to promote the formation of equiaxed grains and interfacial compounds (AlN and AlB2) during solidification. This results in improved strength, with Al‐BNNT composite exhibiting a tensile strength of 47 MPa, 2.3 times higher than its pure Al. Higher strength is attributed to the retention and uniform distribution of BNNT reinforcement in the melt pool, leading to effective load transfer. This study demonstrates the potential of additive manufacturing for producing high‐performance metal matrix composites with novel 1D reinforcements and improved multifunctional properties. [ABSTRACT FROM AUTHOR]

Bragg edge imaging using pulsed neutrons is a non-destructive technique for studying microstructure and texture of materials. It provides two-dimensional visualization of crystallographic information using a pixelated gas electron multiplier detector and a time-of-flight method. In this work, the properties of type 304 austenitic stainless steel samples were studied via Bragg edge imaging. The samples included hot-rolled, cold-rolled and heat-treated specimens, which were characterized to investigate texture, phase fraction and grain growth. The results showed that the crystallite size increased with increasing annealing temperature. The cold-rolled and annealed samples exhibited strong textures, while the hot-rolled sample showed no preferred orientation. The phase volume fraction of induced martensite in the cold-rolled sample was also obtained. Twodimensional maps of microstructures and textures were obtained without destructive processes. The results were validated by electron backscatter diffraction and found to be consistent. This work provides valuable information for non-destructive characterization of bulk materials by performing Bragg edge imaging using the Hokkaido University compact accelerator neutron source. [ABSTRACT FROM AUTHOR]

A micro‐agglomerated particle embedded–thermal barrier coating (TBC) structure was prepared by an improved plasma spray process to withstand the sintering‐induced degradation of TBCs during service. In this study, the sintering resistance and thermophysical and mechanical properties of conventional and novel‐structured TBCs were systematically characterized. The results suggested that the thermal conductivity and sintering shrinkage of the novel‐structured TBCs were approximately 30% lower than those of conventional air plasma spraying TBCs. The elastic modulus of the novel‐structured coating is only 32% of that of the conventional structure after thermal exposure at 1300°C for 100 h. The distinct structure of the coating is the main factor that influences its performance. The relationship between the structural evolution and residual strain of the coating was analyzed using electron backscatter diffraction and transmission electron microscopy. Significant differences were observed in the sintering behavior of the dense matrix and embedded particle regions in the coating. Some columnar grains near the intersplat pores in the dense matrix have similar lattice orientations, and they tend to connect and consequently heal the intersplat pores. The large pores between the agglomerated particles and non‐oriented submicron‐sized grains that constitute these particles are responsible for the sintering resistance of the coating. [ABSTRACT FROM AUTHOR]

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. LAY DESCRIPTION: Electron Backscatter Diffraction (EBSD) is a scanning electron microscope‐based technique for microstructure characterisation. The phase identification is an important function of EBSD. However, commercial 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, which restrict the application of this technology. The interplanar spacing is more diagnostic but generally difficult to apply in pattern indexing because it lacks precision. In our work, 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 without the help of human eyes. The lengths of RLVs were corrected, and then the RLVs were used for evaluating lattice spacing. This method was also effective for fuzzy patterns and partially missing Kikuchi bands. The method did not have additional requirements concerning the number of detected Kikuchi bands and poles. Based on routine pattern recognition, the accuracy of lattice spacing might be effectively improved by correcting the RLVs. This method might be used as an auxiliary approach for differentiating between similar phases to improve the characterisation ability of EBSD and is well‐adapted to the existing commercial EBSD system. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 B1 and B2 structure types. However, since this is impossible for more complicated phases, this approach cannot be directly applied to compounds of arbitrary composition and structure. [ABSTRACT FROM AUTHOR]

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 Δa/a of the mean lattice parameters derived from as many Kikuchi band widths as possible. For dynamically simulated Kikuchi patterns, Δa/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 Δa/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 Zmax, 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 Δa/a < 1.5%. The lattice parameter ratios, and the angles α, β and γ between the basis vectors, are not affected at all. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. Lay description: The basic measurements, and microscopic and chemical structure of the Nile crocodile egg was studied using several microscopy and analytical techniques. It was found that the translucent white egg has two basic layers; the outer shell and inner membrane. The outer shell is further divided into three layers and has openings, called pores extending between the inside and outside of the shell. The highest number of the pores is found around the middle circumference of the egg. The outermost layer is a thin characterless layer made up of calcium and phosphorus, and the middle layer consists of interlocking wedge‐shaped calcite crystals with traces of magnesium, sodium, sulphur and phosphorus. These crystals end in cone‐shaped knobs on the inner aspect of the shell and then also form the third inner layer of the shell. The amount of these knobs, called mammillae, are highest at the equator of the egg and becomes fewer towards the egg poles. The shell thickness follows the same pattern, with the thickest area located at the equator. The second layer of the egg, the membrane is found right beneath the shell and is embedded in the mammillae. The membrane is composed of numerous fibres roughly arranged in parallel sheets of varying directions. Each individual fibre is made up of smaller fibrils clustered together, and forming open channels that run lengthwise through the fibre. [ABSTRACT FROM AUTHOR]

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. Lay Description: Crystals are usually recognized by having distinct facets at their surface. The study of crystals and facets has a long tradition. To identify a crystal facet, one must know the orientation of the surface relative to stacking pattern of the atoms within the crystal. Both these tasks can be accomplished separately, but it is difficult to put the two pieces of information together for hundreds or thousands of crystals at a time. As the dimensions of the electronic circuits become smaller, for example in mobile phones, it is becoming increasingly important to know and control the facets present at the surface of the electrical connections. We measure the topography of the sample surface with Atomic Force Microscopy (AFM) and identify flat parts of the surface as facets. On the same sample, we use a scanning electron microscope with a specialized module (Electron backscatter diffraction, EBSD) to find the directions in which the atoms are stacked below these facets. Combining the data from these two instruments allows us to find the facet types. The mathematical steps needed to do this are described and illustrated. This new technique will allow improved process design and process control in electronics manufacturing and other areas. [ABSTRACT FROM AUTHOR]

Episodic tremor and slow slip (ETS) downdip of the subduction seismogenic zone are poorly understood slip behaviors of the seismic cycle. Talc, a common metasomatic mineral at the subduction interface, is suggested to host slow slip but this hypothesis has not been tested in the rock record. We investigate actinolite microstructures from talc‐bearing and talc‐free rocks exhumed from the depths of modern ETS (Pimu'nga/Santa Catalina Island, California). Actinolite deformed by dissolution‐reprecipitation creep in the talc‐free rock and dislocation creep ± cataclasis in the talc‐bearing rock. This contrast results from stress amplification in the talc‐bearing rock produced by high strain rates in surrounding weak talc. We hypothesize that higher strain rates in the talc‐bearing sample represent episodic slow slip, while lower strain rates in the talc‐free sample represent intervening aseismic creep. This work highlights the need to consider fluid‐mediated chemical change in studies of subduction zone deformation and seismicity. Plain Language Summary: Episodic tremor and slow slip (ETS) are poorly understood styles of fault slip that occur just below the locked part of the megathrust fault where large subduction zone earthquakes occur. Chemical reactions at the depths of ETS can produce new and particularly weak minerals such as talc that change fault behavior but are rarely considered in studies of ETS. Modeling of rock deformation suggests that talc should host ETS fault slip, but this hypothesis has not been tested in the rock record. We investigated deformation of the mineral actinolite in talc‐free and talc‐bearing rocks exhumed from the depths of ETS in modern subduction zones on Pimu'nga/Santa Catalina Island (California) as a record of fault slip. Contrasting microstructures and deformation mechanisms in talc‐free and talc‐bearing rocks are best explained by differences in the rate of deformation (strain rate) between the two rock types. Lower strain rates in talc‐free rocks likely record background creeping (aseismic) deformation and higher strain rates in talc‐bearing rocks likely represent episodic slow slip events. This work suggests that talc may be a key host for slow slip and that future studies must account for new rock types formed by chemical reactions to accurately represent subduction zone deformation. Key Points: Contrasting actinolite microstructures in talc‐free and talc‐bearing subduction interface metasomatic rocks record stress variationsStress amplification in actinolite from talc‐actinolite schist results from high strain rate deformation of surrounding talcHigh strain rates reflect episodic slow slip localized in talc‐actinolite schist under high pore fluid pressures during metasomatism [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Exhumed fossil subduction zones are archives of the deformation conditions and mechanisms from depths not directly accessible. Microstructural analysis of samples exhumed therefrom offers insights into the micromechanics and deformation processes associated with subduction such as earthquakes, slow earthquakes, and aseismic creep. Subducted and exhumed continental metasediments of the Tuscan Metamorphic Units of the Italian Northern Apennines contain a mylonitic foliation and quartz and carpholite dilational hydroshear veins with crack‐and‐seal textures, both developed at blueschist facies conditions (350–400°C, ∼1 GPa). As shown by overprinting relationships and mineral assemblages, these two structure types formed broadly coeval within the stability field of carpholite. Metaconglomerates and metaquartzarenites deformed mainly by dissolution‐precipitation creep and secondary by dislocation creep. Microstructural and electron backscatter diffraction analyses of the veins suggest only limited recrystallization of quartz fibers by subgrain rotation recrystallization, with adjacent metapelite bands acting as decollement horizons, likely by slip on the basal plane of phyllosilicates. We estimated differential stresses of 43–55 MPa and strain rates between 10−13 and 10−14 s−1 from the vein recrystallized quartz fibers. We propose these microstructures and deformation mechanisms to represent a geological evidence of deep episodic tremor and slow slip events in subducted continental metasediments. Pore pressure cyclically reached supralithostatic values triggering tremors causing fracturing of all involved lithotypes. Likely, slow slip was accommodated preferentially by slip on phyllosilicate bands. Aseismic creep occurred mainly by dislocation creep with subgrain rotation recrystallization in vein quartz, slip on the basal plane of phyllosilicates, and dissolution and precipitation creep in the host rock. Plain Language Summary: Rocks exhumed from great depth can help us to investigate processes otherwise non directly accessible. The Italian Northern Apennines comprise exhumed continental sediments that were deformed and metamorphosed at depths of 30–40 km and temperatures of 350–400°C. Broadly coeval continuous and discontinuous deformation is documented as highly deformed zones (shear zones) and veins. We used microstructural analyses and electron microscopy techniques to reconstruct how these rocks deformed and the structures formed. Quartz‐rich metasediments deformed mainly by dissolution and precipitation processes. Weak phyllosilicate‐rich bands accommodated deformation likely by slip on their platy basal planes. Fluid pressure cyclically reached high values that caused failure of the metasediments, with subsequent migration of portion of the fluid and formation of the veins. Veins display only a limited amount of crystal plastic deformation. Quartz paleopiezometry and flow law suggest low differential stresses and average geological strain rates for the deformation of veins. We propose that these structures can be seen as a possible geological record of deep episodic tremor and slow slip events, low intensity and long lasting seismic events associated with slip transients faster than average plate motion. Key Points: Coeval dilational hydroshear veins and mylonites may shed light on deformation mechanisms of deep episodic tremor and slow slip eventsDilational hydroshear veins formed by incremental crack‐seal at supralithostatic pore pressure values and deformed by dislocation creepBlueschist facies mylonites formed mainly by a combination of dissolution‐precipitation creep and slip along phyllosilicate bands [ABSTRACT FROM AUTHOR]

An in situ monoclinic variants selection and rearrangement study on Y2O3–ZrO2 coatings was conducted using electron backscattered diffraction. The sequence growth of variants with the correspondence of (100)m ∼// (010)t, [010]m ∼// [001]t, and [001]m ∼// [100]t (CAB‐OR2) was found initially and converted to the 90°‐rotated sequence growth with (100)m ∼// (100)t, [001]m ∼// [001]t, and [010]m ∼// [010]t (ABC‐OR2) after heat treatment. In another coating, most of the variants first exhibited interleaving growth and changed to typically fourfold growth. This in situ evolution of both variants orientation relationship and arrangement revealed the effects of stress and stress relief on the martensitic transformation. Moreover, the variants selection might be diversified during the cyclic transformation, and the classical phenomenological theory could mainly be proved by the transformation triggered by temperature, instead of external stress. Furthermore, the variants orientation relationship was exactly confirmed by the tetragonal grain reconstructions. In particular, the orientation variation of reconstructed tetragonal grains was also found and could mainly be explained by the behavior of stress relief and dynamic recrystallization. [ABSTRACT FROM AUTHOR]

Coarse‐grained composites of refractory ceramics and refractory metals are a novel approach for materials at application temperatures up to 1500 °C. Al2O3 and the refractory metals Nb and Ta are suitable candidates for enhanced thermal shock capability, as they show similar thermal expansion. During fabrication, a key aspect to consider is the possible formation of additional phases upon interaction of the constituent phases as well as through reaction with the environment. X‐Ray diffraction (XRD) and investigations of the microstructure with scanning electron microscopy methods unveil Al2O3–Nb composite to form NbO, whereas for Al2O3–Ta the ternary compound aluminum tantalate (AlTaO4) is found. Thermodynamic calculations show that the changing oxygen solubility in Nb accounts for the formation of NbO, and explain the absence of a corresponding niobate (AlNbO4) phase. AlTaO4 is identified as the disordered tetragonal high‐temperature modification. [ABSTRACT FROM AUTHOR]

Concrete cores were obtained from houses in eastern Connecticut, USA, that had varying degrees of crumbling foundations and wall cracking. Electron backscatter diffraction (EBSD) was used simultaneously with energy dispersive X‐ray spectroscopy to investigate the degradation of these samples. This combination allowed the precise correlation of elemental composition with mineral crystallography phase mapping. EBSD examination showed the presence of pyrrhotite, pyrite, and marcasite phases in some of the samples, whereas internal sulfate attack (ISA) is triggered by the release of sulfates through the oxidation of such iron sulfides. Secondary expansion products from ISA are associated with foundation cracking, wall bulging, and drastically decreased structural stability. The main contribution of this study is therefore an automated procedure for preparation of concrete samples and analysis of aggregates using EBSD. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Since their discovery in the 1920s, some asymmetric, elongated dinosaur eggs from the Upper Cretaceous of Mongolia have been interpreted as ceratopsian eggs. However, recent views support a maniraptoran affinity mainly based on macroscopic features. Technical advancements in palaeontology provide a novel approach to diagnose maniraptoran eggs, and the discovery of soft ceratopsian eggs makes the debate a timely issue worth revisiting. Here, we analysed Protoceratopsidovum eggshell from southern Mongolia with electron backscatter diffraction and the results were compared with East Asian and North American maniraptoran and ornithischian eggs. The microstructure and crystallography of Protoceratopsidovum confirms the maniraptoran hypothesis, given that it shows diagnostic features of the clade absent from ornithischian (e.g. hadrosaur) eggs. Additional characters, such as egg shape, ornamentation, egg pairing and clutch structure also support a maniraptoran affinity. Protoceratopsidovum has both elongatoolithid (oviraptorosaur egg) and prismatoolithid (troodontid egg) features, and it may bridge the morphological gap between the two established oofamilies. Considering the similarity between Protoceratopsidovum and potential dromaeosaur eggs, at least some Protoceratopsidovum may be deinonychosaur eggs. Fossil localities that yield both deinonychosaurs and Protoceratopsidovum may yield conclusive evidence for the true affinity of this ootaxon. Future discovery of the egg‐laying taxon of Protoceratopsidovum will not only improve our understanding of maniraptoran reproductive biology but also make Protoceratopsidovum a reliable indicator of the palaeobiogeography of that maniraptoran clade. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Thermostatic compression was performed using a Gleeble‐3500 thermal simulation compressor in the temperature range of 900–1200 °C and strain rate range of 0.001–10 s−1. Use the EBSD (Electron backscatter diffraction) analysis the effects of grain orientation and texture on the DRX of Inconel 617 alloy were analyzed, and the effects of the temperature and strain rate on the recrystallization of Inconel 617 alloy were deduced by the construction of a recrystallization model under these conditions. The results show that the grain orientation and texture are sensitive to the temperature and strain rate changes. Discontinuous dynamic recrystallization (DDRX) events of high‐angle grain boundary migration result in nucleation and growth, and continuous dynamic recrystallization (CDRX) of high‐angle grain boundaries occurs, due to the continuous rotation of subgrains. It was found that DRX occurred before the peak strain, and the ratio of the critical strain to the peak strain is lower than that generally obtained in previous work,due to the influence of twins. [ABSTRACT FROM AUTHOR]

In this article, a quasi‐continuous ratio gradient alloy steel (GAS) with a 24CrNiMo high‐strength low‐alloy steel matrix for high‐speed railway brake discs is fabricated by selective laser melting (SLM). The composition of GAS is X% 24CrNiMo + (1–X)% wear‐resistant stainless steel (WSS), in which X is 100, 65, 35, and 0. The relationship between the microstructure and the corrosion resistance is intensively studied by electron backscatter diffraction (EBSD) and potentiodynamic electrochemical equipment. With the increase in the content of WSS, the low angle grain boundaries of the GAS increases, and the microstructure refines and the texture intensity decreases. The passivation film of the external WSS strengthening layer is dense; the corresponding corrosion potential and corrosion current density are −0.109 V and 2.08 × 10−8 A cm−2, respectively. The corrosion current density is about 1% of the substrate 24CrNiMo, and the corrosion resistance of the material is significantly improved. [ABSTRACT FROM AUTHOR]

Herein, the influence of ultrasonic treatment (UST) on the microstructure of AISI‐304 and AISI‐316 stainless steels as two common commercial grades with similar properties but different levels of stacking fault energy (SFE) is compared. The softening effect of the ultrasonic wave on the predeformed structure is demonstrated by microhardness measurements, and the relaxation of tensile residual stresses is affirmed through the X‐ray diffraction (XRD) peak shifting. Electron and optical microscopy reveals a significant impact of ultrasound on the reduction of the deformation twins' fraction. A new mechanism for detwinning under the action of ultrasonic vibration is proposed using electron backscatter diffraction (EBSD) analysis. Reductions of 25% and 34% are detected in dislocation density of the 10% predeformed tensile sample after 300 W UST for the 304SS and 316SS alloys, respectively. The effect of the SFE is discussed, and it turns out that cross‐slip is the main mechanism of dislocation annihilation as a result of UST. Observation of the low‐deformation regions close to the grain boundaries indicates the occurrence of the recrystallization phenomenon during UST. Dislocation annihilation, detwinning, dislocation absorption to grain boundaries, and recrystallization are regarded as the softening and relaxation mechanisms of UST for austenitic stainless steels. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Herein, the thermal compression of 2205 duplex stainless steel is simulated using a thermal simulation testing machine at 850–1100 °/0.01 s−1 and 850–1100 °/10 s−1, and the large deformation zone (LDZ) and free deformation zone (FDZ) of the structure are characterized by electron backscatter diffraction (EBSD). The study results show that the stress–strain curve with a strain rate of 10 s−1 hardens continuously. In addition, ferrite undergoes deformation mostly when the strain is less than 0.33, and strain hardening occurs in austenite after the strain reaches 0.33. As a result, the curve ascends and steepens, and secondary hardening occurs. Continuous dynamic recrystallization (CDRX) is distinctly observed in original ferrite grains, whereas the austenite grains are recrystallized discontinuously due to the bulging high‐angle grain boundaries (HAGBs). Meanwhile, the recrystallization fraction in the large deformation region of both ferrite and austenite is significantly higher than that in the free deformation zone. The orientation distribution function (ODF) diagram analysis reveals that ferrite is mainly composed of the rotation cube {001}<111> texture, and austenite mainly consists of the rolled α‐fiber texture, including brass {011}<211>, Gauss {011}<100>, and {011}<111>. [ABSTRACT FROM AUTHOR]

Accurately indexing pseudosymmetric materials has long proven challenging for electron backscatter diffraction. The recent emergence of intensity‐based indexing approaches promises an enhanced ability to resolve pseudosymmetry compared with traditional Hough‐based indexing approaches. However, little work has been done to understand the effects of sample position and orientation on the ability to resolve pseudosymmetry, especially for intensity‐based indexing approaches. Thus, in this work the effects of crystal orientation and detector distance in a model tetragonal ZrO2 (c/a = 1.0185) material are quantitatively investigated. The orientations that are easiest and most difficult to correctly index are identified, the effect of detector distance on indexing confidence is characterized, and these trends are analyzed on the basis of the appearance of specific zone axes in the diffraction patterns. The findings also point to the clear benefit of shorter detector distances for resolving pseudosymmetry using intensity‐based indexing approaches. [ABSTRACT FROM AUTHOR]

A new method for electron backscatter diffraction ab initio indexing is reported that adopts several methods originally invented for powder indexing. Distribution rules of systematic absences and error‐stable Bravais lattice determination are used to eliminate the negative influence of non‐visible bands and erroneous information from visible bands. In addition, generalized versions of the de Wolff figures of merit are proposed as a new sorting criterion for the obtained unit‐cell parameters, which can be used in both orientation determination and ab initio indexing from Kikuchi patterns. Computational results show that the new figures of merit work well, similar to the original de Wolff Mn. The ambiguity of the indexing solutions is also pointed out, which happens in particular for low‐symmetry cells and may generate multiple distinct solutions even if very accurate positions of band centre lines and the projection centre are given. It is supposed that this is the reason why indexing was successful in an orthorhombic case but not in a triclinic cell. [ABSTRACT FROM AUTHOR]

Potentiostatic slow strain rate testing was conducted on stress corrosion cracking (SCC) test specimens exposed to ethanolic environments prepared from pure dehydrated ethanol. The mechanism of SCC in such environments is not well‐understood. Cracks of various types—intergranular and transgranular open cracks, and sharp closed transgranular cracks—were found by altering several testing parameters. The presence of chloride was found to be essential for crack initiation. A scanning electron microscope examination indicated that an "anodic" cracking mechanism, not necessarily slip dissolution, was most likely operating at high elongations. Sharp, closed transgranular cracks, with a maximum depth of 4 µm, were detected at elongations below 3% in ethanol solutions containing 2.5‐mM LiCl. A focused ion beam was used to extract such a transgranular crack tip for analytical transmission electron microscopy using electron energy loss spectroscopy, which confirmed that the crack was in a ferrite grain. The sharp closed transgranular cracks seem to ally with the cracks observed in CO–CO2–H2O and anhydrous ammonia environments, which are proposed to grow by unique cleavage mechanisms. The possibility of embrittlement by carbon interstitials produced by ethanol electro‐oxidation within the crack is discussed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Ultra high pressure (UHP) metamorphism observed in continental terranes implies that continental crust can subduct to ~40 kbar before exhuming to the surface. This process is one of the least understood and widely debated parts of the orogenic cycle. The dominantly felsic composition of UHP continental terranes means that many petrology‐based techniques for determining peak pressures and temperatures are often not possible. In such cases, the detection of UHP conditions depends on the preservation of coesite, a rarely preserved mineral in exhumed UHP terranes as it rapidly transforms to quartz on decompression. Consequently, the qualitative identification of palisade quartz microstructures that form during the retrograde transformation of coesite to quartz is often used to identify UHP terranes. In this study, we conduct electron backscatter diffraction and misorientation analysis of palisade quartz inclusions in the coesite‐bearing pyrope quartzite from the Dora Maira massif in the Alps, and matrix‐scale palisade quartz in the Polokongka La granite from Tso Morari in the Ladakh Himalaya, in order to quantitatively define crystallographic characteristics of quartz after coesite. The repeatability of our observations in two unrelated occurrences of UHP rocks supports our interpretation that the following features provide a systematic and predictable set of criteria to identify the coesite to quartz transition: (1) Quartz crystallographic orientations define spatially and texturally distinct subdomains of palisade quartz grains with 'single crystal' orientations defined by distinct c‐axis point maxima. (2) Adjacent subdomains are misorientated with respect to each other by a misorientation angle/axis of 90°/. (3) Within each subdomain, palisade quartz grain boundaries commonly have intra‐ and inter‐granular misorientations of 60°/[0001], consistent with the dauphiné twin law. Our observations imply that the coesite‐quartz transformation is crystallographically controlled by the epitaxial nucleation of palisade quartz on the former coesite grain, specifically on potential coesite twin planes such as (1‐01) and (021). [ABSTRACT FROM AUTHOR]

Herein, the effect of sputtering rate on the fraction of special grain boundaries in 5xxx series Al–Mg alloys is explored. Samples are synthesized via interrupted direct current (DC) magnetron sputtering with varying deposition rates, and the grain size and grain boundary character are evaluated with electron backscatter diffraction (EBSD). The highest sputtering rate (7 nm s−1) leads to an increase in the total number of special grain boundaries, ≈1.5× greater than that of the lower rates. Increased thermal energy and enhanced stress relaxation during film growth promote the formation of Σ3 and Σ7 boundaries. [ABSTRACT FROM AUTHOR]

There is a growing interest in ab initio indexing of electron backscatter diffraction (EBSD) patterns. The methods of solving the problem are presented as innovative. The purpose of this note is to point out that ab initio EBSD indexing belongs to the field of indexing single‐crystal diffraction data, and it is solved on the same principles as indexing of patterns of other types. It is shown that reasonably accurate EBSD‐based data can be indexed by programs designed for X‐ray data. [ABSTRACT FROM AUTHOR]

The transformation behavior between iron oxides and oxyhydroxides like magnetite, hematite and goethite is still not entirely understood. Crystallographic similarities allow one to predict topotactic relationships between them. The related crystallographic aspects have been explored by means of electron backscatter diffraction (EBSD). Samples from natural aggregates of magnetite, hematite and goethite were collected from iron‐formation rocks that outcrop in the southeast of Brazil, in a region known for large deposits of iron and other ores. EBSD misorientation data indicate a pronounced relationship between these iron phases. The transformation seems to be related to the oxygen framework. The original close‐packed cubic arrangement of O atoms in magnetite changes to a hexagonal close‐packed framework in hematite, i.e. {111} of magnetite is parallel to {0001} of hematite. The matrix in which the magnetite grains are embedded is made of aggregates of hematite and goethite. In the matrix, the coincidence observed in the magnetite grains is not observed. On the other hand, the well known twin boundary relationships already described for these mineral phases can be observed here as an orientation relationship in three‐dimensional misorientation space. The spatial data of axis–angle pairs suggest that the twin boundaries serve as facilitating surfaces for phase transformation in the Fe–O–OH system. The main conclusion of this study is that the transformation occurred in the solid state with the newly transformed goethite inheriting the crystallographic orientations of the former crystals and that this phenomenon is better recognized by combining observations of misorientation relationships. In the matrix, such a relation is not observed and, for that reason, the minerals in the matrix are thought to have been formed by a different process, which might have involved dissolution and precipitation of the phase newly out of solution. [ABSTRACT FROM AUTHOR]

The micro‐texture of ferritic stainless steel generated by rolling and annealing processes is supposed to behave plastic anisotropy and heterogeneous strain response during forming, especially for the high Cr content ferritic stainless steel with single ferrite phase. The relation between crystallographic orientations and their strain responses during loading are analyzed for a 21% Cr ferritic stainless steel sheet. The crystallographic orientation distributions in surface and center layers as well as in cross section are characterized by an electron backscatter diffraction (EBSD) method. It indicates that texture gradients along thickness with center layer having a higher density of <111>//ND texture are formed. Some grain clusters with similar oriented grains gathering together to be parallel to the rolling direction are observed. Then, the experimental orientation distributions are condensed and incorporated into a developed crystal plasticity finite‐element model (CPFEM), in which the multiple slip systems and the interaction between neighbor grains are considered. The simulation results confirm that the heterogeneous distributions of normal strain and shear strain preserved for the different crystal orientation grains result in the surface ridging. The texture gradients can help to decrease the tendency of surface ridging. The simulation results show a reasonable agreement with the tensile test results. [ABSTRACT FROM AUTHOR]

Metapelites from the inverted Barrovian sequence in the Sikkim Himalaya (northeast India) are shown to be largely continuous with respect to their bulk rock compositions, microstructures and pressure–temperature–time–deformation (P–T–t–D) histories. However, the upper garnet–lower staurolite zone demarcates a region of microstructurally anomalous post‐kinematic garnet populations contained within strongly segregated matrices. The different microstructures within samples from this region cannot be attributed to differences in their thermobarometric histories or bulk compositions, but are instead interpreted to represent an otherwise unexposed level of the Daling Group that is now exposed along a post‐metamorphic thrust splay. These heterogeneous samples contain several discrete garnet populations that progressively crystallized with increasing P–T. Garnet populations that experienced the most protracted growth now form complex polycrystals that exhibit crystallographically controlled and morphologically irregular interfaces adjacent to micaceous and quartzofeldspathic domains respectively. Electron backscatter diffraction indicates that these polycrystalline garnet structures contain numerous coalesced porphyroblasts that are structurally uncorrelated across their grain boundaries. However, a crystallographically preferred orientation at the polycrystal scale is interpreted to derive from epitaxial crystallization of early‐formed garnet porphyroblasts on precursor mica. Later‐nucleated porphyroblasts within polycrystals preferentially concentrated towards quartzofeldspathic domains, with the overall nucleation distribution likely controlled by a complex interplay between chemical heterogeneities, strain partitioning and epitaxial crystallization. The subsequent growth of these polycrystals was equally spatially heterogeneous; it was moderated by differences in the efficiency of grain boundary transfer between quartzofeldspathic and micaceous domains that precluded thin section‐scale chemical equilibration. In contrast to samples from Sikkim containing more typical porphyroblastic populations in continuous and disseminated matrices, heterogeneous availability of garnet‐forming components within this strongly layered matrix is shown to have resulted in grain‐scale variations in growth rates and the spatial juxtapositioning of interface‐controlled microstructures and locally equilibrated chemical compositions with those that were transport controlled. [ABSTRACT FROM AUTHOR]

During continental collision, large tracts of crust are mobilized along major shear zones. The metamorphic conditions at which these zones operate, the duration of thrusting, and the deformation processes that facilitated hundreds of km of tectonic transport are still unclear. In the Scandinavian Caledonides, the Lower Seve Nappe displays a main mylonitic foliation with thickness of ~1 km. This foliation is overprinted by a brittle‐to‐ductile deformation pattern localized in C‐ and C′‐type shear bands proximal to the tectonic contact with the underlying Särv Nappe. Thermobarometry of amphibolites and micaschists suggests a first high‐pressure stage at 400–500°C and 1–1.3 GPa recorded in mineral relics. The main mylonitic foliation developed under epidote amphibolite facies conditions along the retrograde path from 600°C and 1 GPa to 500°C and 0.5 GPa. Age dating of synkinematic titanite grains in the amphibolites indicates that this mylonitic fabric formed at around 417 ± 9 Ma but older ages spanning 460–430 Ma could represent earlier stages of mylonitization. The shear bands developed at lower metamorphic conditions of 300–400°C and ~0.3 GPa. In the micaschists, the recrystallized grain size of quartz decreases toward the shear bands. Monomineralic quartz layers are eventually dismembered to form polyphase aggregates deforming by dominant grain size sensitive creep accompanied by slip in muscovite and chlorite. Plagioclase zoning truncations suggest that the shear bands originated by fracturing followed by ductile deformation. The results suggest protracted and long‐lasting shearing under amphibolite to greenschist facies conditions during the juxtaposition, stacking, and exhumation of the Lower Seve Nappe. Key Points: In the Lower Seve Nappe 1 km‐thick mylonitic foliation formed at amphibolite facies conditions between ~460 and ~417 MaToward the base of the nappe the foliation is overprinted by a brittle‐to‐ductile fabric of greenschist facies conditions (~417 to 400 Ma)These fabrics formed due to protracted and long‐lasting shearing during the exhumation and assembly of the Seve Nappe Complex [ABSTRACT FROM AUTHOR]

Resolving pseudosymmetry has long presented a challenge for electron backscatter diffraction and has been notoriously challenging in the case of tetragonal ZrO2 in particular. In this work, a method is proposed to resolve pseudosymmetry by building upon the dictionary indexing method and augmenting it with the application of global optimization to fit accurate pattern centers, clustering of the Hough‐indexed orientations to focus the dictionary in orientation space and interpolation to improve the accuracy of the indexed solution. The proposed method is demonstrated to resolve pseudosymmetry with 100% accuracy in simulated patterns of tetragonal ZrO2, even with high degrees of binning and noise. The method is then used to index an experimental data set, which confirms its ability to efficiently and accurately resolve pseudosymmetry in these materials. The present method can be applied to resolve pseudosymmetry in a wide range of materials, possibly even some more challenging than tetragonal ZrO2. Source code for this implementation is available online. [ABSTRACT FROM AUTHOR]