Microtextural Characterization Research Articles

Trace elements in ilmenite, titanomagnetite and apatite unravel the petrogenesis of Fe-Ti-P-(+/-Zr) rich rocks and associated nelsonite from the Raftsund intrusion, Vesterålen-Lofoten AMCG suite, Northern Norway

The formation of Fe-Ti-P- (+/− Zr)-rich rocks and nelsonite (Fe-Ti oxide-apatite +/− zircon-rich rocks mostly devoid of silicates) remains poorly understood. Accumulation of mafic minerals during the evolution of magma by fractional crystallization and silicate-liquid immiscibility are the two main processes considered. However, the latter process is difficult to identify in intrusive rocks as melt compositions are rarely preserved. In this study, we analyzed the trace element content of ilmenite, titanomagnetite, and apatite from the Raftsund intrusion, a 1800 Ma monzonitic to syenitic batholith belonging to the Lofoten-Vesterålen anorthosite-mangerite-charnockite-granite suite in order to test whether liquid-immiscibility was responsible for the formation of Fe-Ti-P-rich rocks. In addition, we extend the study to a new nelsonite occurrence. Detailed microtextural characterization of apatite in the monzonite shows evidence of metasomatic alteration in the form of thin rims of allanite, whereas apatite in the nelsonite contains small monazite inclusion along fractures. Ilmenite and titanomagnetite, not affected by later events, record enrichments in elements that should have behaved compatibly (Mg, Sc, Co, Cu, V) and incompatibly (Zr, Mn, Zn) in a fractionating system where zircon and sphalerite are absent from the mineral assemblage. This observation supports the liquid immiscibility hypothesis. Similar enrichments are observed in other parts of the system, including the nelsonite. However, the high field strength elements are affected by the stability and crystallization of abundant zircon and ilmenite, resulting in lower concentration of these element in the Fe-Ti oxides. The Fe-Ti oxides in the nelsonite record enrichments that are more pronounced than the Fe-Ti oxides in the surrounding rocks, which indicate that not only liquid immiscibility is responsible for the genesis of the nelsonite, but that the Fe-rich melt from which the Fe-Ti oxides crystallized was more enriched in trace elements than the Fe-Ti-P-rich rocks in the rest of the intrusion. Enrichment in transition metals (Co, V, Cu) is related to mingling with a less evolved monzodioritic magma, which most likely triggered the liquid immiscibility that formed the nelsonite. Fractionation and segregation of Fe-rich silicates, such as augite and fayalite, are necessary to explain the formation of the nelsonite.

EBSD Characterization of Microstructure and Micro-texture in a Friction Stir-Welded DP600 Steel

EBSD Characterization of Microstructure and Micro-texture in a Friction Stir-Welded DP600 Steel

Mineralogical and microtextural characterization of eco-friendly concrete for marine infrastructures: Methodologies for the MARINEFF Project

The European cross-border Project MARINEFF explores the use of eco-friendly concrete materials in the construction of marine structures (oyster bed modules, dykes, boat moorings and rockpools). The structures and materials are designed to protect and improve the local biodiversity of the marine environment of the Channel / La Manche. This paper focuses on the mineralogical and microtextural characterization of the concrete materials. The aim is to introduce how advanced analytical methods have been employed to gain an understanding of the evolution of the materials, in particular their response to immersion into the sea. Our methods include the traditional techniques for examining concrete materials (optical microscopy, scanning electron microscopy, X-ray diffraction), but also introduces the benefits of mineralogical methods that go beyond the current “state-of-the-art” (automated scanning electron microscopy by QEMSCAN®, electron-probe microanalysis). Our results offer detailed insight into the controls on the compositional and structural evolution of the materials.

Microtextural Characterization of Additively Manufactured SS316L After Hot Isostatic Pressing Heat Treatment

Microtextural Characterization of Additively Manufactured SS316L After Hot Isostatic Pressing Heat Treatment

Characterization of Microstructure and Microtexture in a Cold-Rolled and Intercritically Annealed Dual-Phase Steel

Characterization of Microstructure and Microtexture in a Cold-Rolled and Intercritically Annealed Dual-Phase Steel

Editorial for Special Issue “Microtexture Characterization of Rocks and Minerals”

Microtextures, the physical or structural aspects of minerals and rocks, may include the interrelationships of minerals, the preferred orientation of grains, the internal textures of minerals, etc [...]

Inversion methodology for ultrasonic characterization of polycrystals with clusters of preferentially oriented grains

Titanium alloys are widely used in the aerospace industry. However, due to presence of microtexture, which is characterized by preferred crystallographic orientation clustering of thousands of alpha crystallites, cold dwell fatigue may significantly reduce the part life. To satisfy the practical need for nondestructive microtexture characterization, an inverse ultrasonic methodology is proposed to quantify mean parameters of microtexture regions (MTRs) having ellipsoidal shapes. One limitation of previous model-based ultrasonic inversion methods is required knowledge of elastic constants of the crystallites, which are rarely available for engineering alloys. This study overcomes this constraint by adopting the far field attenuation model, JASA, 137 (5), 2655–2669 (2015), and the backscattering model for ultrasonic wave interaction with microtexture. In the methodology developed, all necessary averaged MTR characteristics are obtained solely from directional ultrasonic measurements (backscattering, attenuation, and velocity) without a prior knowledge of material microstructures or elastic properties of different material phases. The inversion method is illustrated by simulations. To support the inversion methodology, the mean MTR sizes, morphology, and elastic scattering factors are determined from the ultrasonic experiment on a Ti-6242 alloy sample. The inversion results are compared with destructive electron backscatter diffraction (EBSD) analysis from which the MTRs are segmented using a non-contiguous grouping criteria. Good agreement is found.

Characterization of Microstructure, Microtexture, and Mechanical Response in UNS N08825 Superalloy/AISI 316L Stainless Steel Welds by Electron Backscatter Diffraction Analysis

Characterization of Microstructure, Microtexture, and Mechanical Response in UNS N08825 Superalloy/AISI 316L Stainless Steel Welds by Electron Backscatter Diffraction Analysis

Effect of substrate type on RF magnetron sputtered CuInS2 thin films properties based on nanoparticles synthesized by solvothermal route

Stereometric and fractal analyses have been performed on the three-dimensional surface microtexture of the sputtered copper indium disulfide films on various substrates. The target used in the sputtering was made from nanoparticles synthesized by the solvothermal route. The effects of substrate on structural and morphological properties of the films were investigated. The obtained CuInS2 films were polycrystalline textured, preferentially oriented in (112) crystallographic direction. Also, the (112) peak intensity changes with the substrate type. From atomic force microscopy (AFM) analysis, it can be concluded that the growth of the film on molybdenum substrate is promising for photovoltaic applications particularly as absorber layer in solar cells. The surface microtexture characterization in terms of surface dimensions, volume, curvature, shape was analyzed according to ISO 25,178–2: 2012 standard.

Molecular simulation and microtextural characterization of quartz dissolution in sodium hydroxide

This study uses empirical experimental evidence and Material Studio simulations to explain the interaction of sodium hydroxide (NaOH) with quartz. Density functional theory (DFT) calculations were carried out using the Cambridge Serial Total Energy Package. In addition, quartz grains subjected to dissolution in NaOH were characterized using scanning electron microscopy. The so-called O-middle termination in the quartz tetrahedron structure, typified by a solitary exposed oxygen atom at the surface, is the most susceptible SiO2 terminations to NaOH attack, as it is associated with the lowest surface energy. The adsorption energy values are − 1.44 kcal/mol and − 5.90 kcal/mol for a single atom layer and five-layered atomic structure, respectively. The DFT calculation reveals intramolecular energy is the dominant adsorption energy, followed by a weak van der Waals energy. The NaOH adsorbed on quartz (001) surface constitutes a lower band gap of 0.138 eV compared to cleaved quartz (001) surface (0.157 eV). In addition, the energy range of NaOH adsorbed on quartz is wider (− 50 to 10 eV), compared to (001) quartz (− 20 to 11 eV). The dissolved quartz showed the precipitation of sorbed silicate phases due to incongruent reactions, which indicates new voids and etch pits can be created through the cleaving of the sodium silicates sorbed into the quartz surface. The adsorption energy for NaOH interactions with reservoir sandstone was significantly higher compared to the solitary crystal grains, which can be attributed to the isotropic deformation of a single crystal, and non-uniform deformations of adjacent grains in granular quartz of sandstone reservoir. It can be inferred that exposure to NaOH will affect the structure and reactivity of quartz. The quartz surface textural study indicates that dissolution of crystalline (granite) and clastic rocks (sandstone) is critical to the development of voids, which will improve permeability by providing channels and routes for the passage of hydrothermal and reservoir fluids.

Geochemical Evaluation and Pore Type Characterization of Carbonaceous Rich Facies in Brown Shale Formation, Central Sumatra Basin

DOI:10.17014/ijog.7.2.121-133Brown Shale Formation of Pematang Group is a key source rock in the Central Sumatra Basin. The formation consists of three lithofacies: algal rich facies, mixed algal-carbonaceous facies, and carbonaceous rich facies. This paper focuses on evaluating the geochemistry and on characterizing the porosity of the carbonaceous rich facies. Geochemical evaluation of the carbonaceous source rocks was conducted using Rock-Eval pyrolysis, while mineralogy and microtextural characterization were assessed by incident light microscopy and scanning electron microscopy (SEM). The results show that the organic components of the carbonaceous source rocks are predominantly composed of vitrinite with minor inertinite and liptinite. The geochemical characteristics indicate that the carbonaceous rich facies could be ranked as a good to excellent level in terms of source rock potential with high TOC content, mainly containing kerogen type III as a gas prone potential. SEM results show that the pore types in the carbonaceous source rocks can be classified into three main types: porous floccules, organic-porosity, and intraparticle pores. Thus, the carbonaceous rich facies of the Brown Shale Formation contains gas prone source rocks with good generation potential, as well as organic rich shale unconventional reservoirs.

Fractal characterization of surface microtexture of Ti6Al4V subjected to ultrasonic vibration assisted milling

The high-frequency tool vibration occurring during ultrasonic vibration cutting results in a formation of unique micromorphology of the machined surface. Different microtextures are known to have a substantial effect on the workpiece service performance. In this study, an attempt is made to assess this effect quantitatively for a more accurate characterization of the processed surface. The dependence between the contour root mean square deviation and fractal dimension is derived via the fractal theory. The concept of characteristic fractal dimension is proposed and successfully applied to Ti6Al4V surfaces subjected to ultrasonic vibration assisted milling (UVAM) with various spindle rotation speeds and vibration amplitudes. The experimental results obtained strongly indicate that smaller characteristic fractal dimensions correspond to more regular surface microtextures and contour curves, which proves the validity of the characteristic fractal dimension representation. Besides, the lower the characteristic fractal dimension of the surface, the shorter the time to reach the stable friction phase during dry friction.

A geochemical and micro-textural comparison of basalt-hosted chalcedony from the Jurassic Drakensberg and Neoarchean Ventersdorp Supergroup (Vaal River alluvial gravels), South Africa

South African basalt-hosted chalcedonies provided an ideal case study, to (a) achieve information about the origin of mineral-forming fluids, the process of chalcedony formation and weathering alteration and (b) to verify if the geochemical and micro-textural characterization of chalcedony allowed multiple provenances to be distinguished. For the first time, Drakensberg chalcedonies from the Karoo Jurassic basalts and Windsorton chalcedonies from the alluvial environment of the Vaal River (traversing the Allanridge basaltic–andesitic lavas) were investigated by optical microscopy, laser ablation inductively coupled plasma mass spectroscopy and isotope ratio mass spectrometry (16O, 18O). The results showed that the compositional differences observed in Drakensberg and Windsorton chalcedonies could not be explained by changes in host rocks composition. The tholeiitic basaltic–andesitic lavas of the Allanridge Formation (Pniel Group, comparison term for Windsorton samples) and the tholeiitic basaltic–andesitic lavas of the Golden Gate Unit (Drakensberg Group, comparison term for Drakensberg specimens) proved to be very similar, also in terms of alteration degree. Conversely, both geochemical and oxygen isotope compositions clearly supported a relatively low temperature, hydrothermal origin for all the investigated chalcedonies, further indicating that differences mostly occurred during their formation (fluid circulation). Moreover, several characteristics suggested deposition in non-equilibrium conditions, although oxidizing conditions were most likely. Weathering processes were effective in the alluvial environment only, leading to a wider compositional heterogeneity of Windsorton chalcedonies with respect to Drakensberg samples. Lastly, a correlation between color and chromophores (Fe and Mn) amounts was lacking while a correlation between the geochemical composition and the texture was clearly observed in several specimens.

Characterization of microtexture of 316L stainless steel fiber after multi-pass drawing by electron backscatter diffraction

The microstructure and microtexture of 316L stainless steel fibers (SSFs) after multi-pass cold drawing with intermediate heat treatment were investigated in this study. The crystalline phases of SSFs were identified and quantified using X-ray diffraction (XRD) analysis. Grain orientation and boundary characterization in the mantle and core regions of drawing direction (DD) were analyzed through electron backscatter diffraction (EBSD). The coincident site lattice approach provides beneficial information for defining twin boundary and analyzing the orientation relationship between neighboring grains on the Σ3 segment. Three crystalline phases, γ, α, and σ, could be seen in XRD profiles. The formation mechanism of deformation twins was found, and two types of twin boundaries were observed in the drawn fibers by EBSD. The twin boundary generated between a {112}〈111〉 grain and a 〈100〉//DD grain is believed to nucleate at a high-angle grain boundary and then bulge into the copper grain.

Defining shear zone boundaries using fabric intensity gradients: An example from the east-central Nepal Himalaya

Uranium-lead (U-Pb) zircon geochronology, whole-rock geochemistry, and petrographic observations indicate that specimens from a suite of variably deformed granite and orthogneiss from the Okhaldungha region of east-central Nepal share a common origin. Microtextural characterization and quartz crystallographic fabric preferred orientation analyses of these same specimens outline a strain gradient that marks the location of a shear zone boundary. The location of this boundary, at the base of the orthogneiss, coincides with one of the interpreted locations of the Main Central thrust, though it cannot be uniquely identified as such. This study provides the first steps toward empirical constraints on the location and geometry of thrust structures in the region, helping to clarify the complex local kinematic framework. These methods not only help in assessing orogenic models of the Himalaya, but may also be applied to investigating other orogenic systems where the potential location of shear structures is contested.

Kinetics of reactive diffusion between solid La<sub>2</sub>GeO<sub>5</sub> and gases [GeO + 1/2O<sub>2</sub>

We successfully prepared the polycrystalline lanthanum germanate oxyapatite (LGO) by the reactive diffusion between solid La2GeO5 and gases [GeO + 1/2O2] during isothermal heating at 1573–1723 K for 2–50 h. The reaction products were investigated by polarizing-microscopy for microtexture characterization, Raman spectroscopy for phase identification, and X-ray diffractometry for determination of the {00l}LGO texture fractions. The LGO polycrystals were highly c*-axis-oriented, and hence the Lotgering factor f00l ranged, regardless of annealing temperatures, between 0.94 and 0.99. The thickness (l/m) of LGO layer steadily increased with the increase of annealing time (t/s) in accordance with a parabolic relationship of l = [exp(−1.502 × 104/T − 5.233)] × t1/2. The growth of LGO layer was predominantly controlled by volume diffusion of GeO2 component, with the activation energy being ca. 125 kJ mol−1.

Characterization of Microstructure, Texture, and Microtexture in Near-Alpha Titanium Mill Products

Microstructure, texture, and microtexture in Ti-6Al-2Sn-4Zr-2Mo-0.1Si billet/bar of three different diameters (57, 152, and 209 mm) were quantified using backscattered electron imaging and electron backscatter diffraction. All three billets exhibited a microstructure comprising a large fraction (≥70 pct) of primary alpha particles, the average size of which decreased and aspect ratio increased with increasing reduction/decreasing billet diameter, or trends suggestive of low final hot working temperatures and/or slow cooling rates after deformation. Appreciable radial variations in the volume fraction and aspect ratio of alpha particles were noticeable only for the smallest-diameter billet. Alpha-phase textures were typical of axisymmetric deformation, but were relatively weak (~3× random) for all billet diameters. By contrast, bands of microtexture, which were multiple millimeters in length along the axial direction, were relatively strong for all of the materials. The intensity and radial thickness of the bands tended to decrease with decreasing billet diameter, thus indicating the important influence of imposed strain on the elimination of microtexture and the possible influence of surface preform microstructure following the beta quench on the evolution of microstructure and microtexture.

Physicochemical and microtextural characterization of activated carbons produced from water steam activation of three bamboo species

The bamboo species Guadua angustifolia, Bambusa vulgaris striata and Bambusa oldhamii, were used as raw materials to obtain sixteen activated carbons. The physicochemical characterization showed wide adsorption capacity values (measured as iodine number) ranging from 280 to 1500mg/g, activation yields from 80 to 85%, average point of zero charge ≈9.9 and high content of quinonic surface groups. The influence of the bamboo species, particle size, time and temperature on the final surface properties was analysed using factorial experimental design methodology. Results indicated that the maximum adsorption capacity was achieved with B. vulgaris striata and 4h of activation time. The content of superficial oxygenated acidic groups on the samples were identified as the result of the third order interaction (raw material, time and temperature) allowing the control of the surface polarity on the final activated carbons. The scanning electron microscopy micrographs showed the shape conservation of the raw material after carbonization and activation stages. Transmission electron microscopy examinations suggest that structure of the prepared material is formed by highly disordered graphene-like layers as it was confirmed with the diffuse diffraction rings observed by selected area diffraction pattern and the shape of the carbon-K energy-loss near edge structure.

Microstructure and Microtexture Evolution of Shear Localization in Dynamic Deformation with Different Strains in Annealed Copper

Shear localizations with different strains in annealed copper were obtained by a modified split Hopkinson pressure bar. Microstructure and microtexture evolution of the shear localization regions were examined using optical microscopy, electron backscatter diffraction technique, and transmission electron microscopy. The results show that both the mechanical response and deformation behavior are correlated closely to the shear strains. The elongated dislocation cells, stretched subgrains, and the refinement of subgrains are observed within shear localizations during dynamic deformation. Ultrafine grains of 100 to 300 nm with high-angle-boundaries are produced within the shear band with the shear strain of 5.8. Microtexture characterization reveals that a stable orientation, in which 〈110〉 directions of the crystals tend to align with the shear direction, develops both in the deformation and recrystallization areas. The {111} planes of the crystals tend to parallel to the shear plane in the deformation area, whereas the aggregated extent of this orientation becomes weak in the recrystallization area. In addition, some grains exist with the {100} planes parallel to the shear plane in the deformation and recrystallization areas. The rotational dynamic recrystallization is a reasonable mechanism for the microstructure evolution. The effects of cooling stage on the growth of grains and the change of dislocation density are estimated as a complementarity to this mechanism.

Shear and multiaxial responses of oxygen free high conductivity (OFHC) copper over wide range of strain-rates and temperatures and constitutive modeling

In this paper, the experimental response of oxygen free high conductivity (OFHC) copper under multiaxial loading conditions is presented, along with quasi-static and dynamic response under uniaxial compression loading. The multiaxial experiments were performed under non-proportional loading conditions, where the sample was subjected to uniaxial loading for a predetermined strain followed by biaxial loading. These experimental results provide a comprehensive data set for constitutive modeling of the material response at finite strains, over a wide range of strain-rates and temperatures. The observed strain-rate and temperature dependent responses under uniaxial loading are shown to correlate closely using the Khan–Huang–Liang (KHL) constitutive model; the model is shown to be in close agreement with other published experimental results [Khan, A.S., Liang, R., 1999. Behavior of three BCC metal over a wide range of strain rates and temperatures. International Journal of Plasticity 15, 1089–1109; Nemat-Nasser, S., Li, Y., 1998. Flow stress of F.C.C polycrystals with applications to OFHC Cu. Acta Materialia 46 (2), 565–577]. This constitutive model is further demonstrated to predict the observed material response accurately, using the material constants determined from uniaxial loading results during proportional and non-proportional loading experiments. The micro-texture characterization of as-extruded, annealed and deformed samples was performed to investigate the effect of temperature and strain-rate on texture evolution of OFHC copper. Grain average misorientation (GAM) was used to reveal the deformation heterogeneity and orientation gradients in deformed samples.