Search

The interactions between hydrogen and crystallographic defects are the key to understanding hydrogen induced localized plasticity or damage mechanisms. However, unraveling such interactions based on the resulting mechanical effects alone can be challenging, due to the spectrum of various effects hydrogen can create in a given microstructure. Pre-deformation or post-mortem characterization of hydrogen segregation has similar limitations, as they can only provide snapshots of these complex processes with challenging spatial and temporal scales. To tackle this, we design in situ experiments that combine electron channeling contrast imaging (ECCI), electron backscattered diffraction (EBSD), and desorption spectroscopy, to investigate hydrogen defect interactions, under no external loading. We show that the inhomogeneous hydrogen distribution within microstructures can cause long-range (>200 nm) dislocation rearrangements. Interpretation of these results as manifestations of boundary-segregation induced stress suggests that microstructural characteristics on either side of the boundary should also play an important role. We provide quantitative assessments of these microstructure neighborhood effects and discuss additional contributions from hydrogen-induced changes in stacking fault energy and elastic modulus. • Hydrogen presence can alter defect substructures and local crystal orientation. • Defect activity likely arise from local lattice accommodation of H-induced stresses. • HE-resistant design lies in uniform H-distribution and accommodating textures. [ABSTRACT FROM AUTHOR]

Petrologic investigation of the El Ali IAB iron meteorite (Somalia) revealed three new minerals: elaliite [ F e 8 2 + Fe3+(PO4)O8, IMA 2022-087], elkinstantonite [Fe4(PO4)2O, IMA 2022-088], and olsenite [KFe4(PO4)3, IMA 2022-100]. The name elaliite recognizes the occurrence of this mineral within the El Ali meteorite, originally located at 4° 17′ 17″N, 44° 53′ 54″E. Elkinstantonite is named after Linda (Lindy) Elkins-Tanton (b. 1965), a planetary scientist and professor in the School of Earth and Space Exploration at Arizona State University. The name olsenite is in honor of Edward J. Olsen (1927–2020), the former Curator of Mineralogy and Meteorites at the Field Museum of Natural History in Chicago (1960–1991). The new minerals and their names have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association. The holotype specimens of elaliite, elkinstantonite, and olsenite consist of the polished block mount with accession number MET11814/2-1/EP1 deposited in the University of Alberta Meteorite Collection. Elaliite, elkinstantonite, and olsenite occur along with wüstite, troilite, sarcopside, and Ca-bearing graftonite within inclusions in the iron-nickel metal (kamacite, 9.4 wt% Ni) that makes up the bulk of the El Ali sample. The empirical formulas determined by electron probe microanalysis for elaliite, elkinstantonite, and olsenite are: ( F e 7.943 2 + F e 1.020 3 + Cr0.010Ni0.006Ca0.004Mn0.004)Σ8.987(P0.932Si0.077S0.005)Σ1.014O12,( F e 3.947 2 + Mn0.016Ni0.003Ca0.001Cr0.001)Σ3.968(P1.986Si0.014S0.013)Σ2.013O9, and (K0.820Na0.135Ca0.004)Σ0.959(Fe3.829Mn0.050)Σ3.879(P2.972S0.058Si0.017)Σ3.047O12, respectively. Electron backscatter diffraction was used to confirm the crystal structures of the three new minerals. Raman spectra for all three minerals are also presented. [ABSTRACT FROM AUTHOR]

Lacustrine stromatolites serve as important archives for recording environmental changes, and the detailed examination of their microfabrics is essential for understanding their formative processes and the environmental changes embedded within them. This study explored the application of Electron Backscatter Diffraction combined with Energy‐Dispersive X‐ray Spectroscopy to investigate a well‐preserved middle Cretaceous lacustrine stromatolite from south‐eastern Korea, unveiling ultra‐high‐resolution sedimentary processes that are often challenging to observe using conventional methods. Two types of microsparitic layers and one type of crystalline layer are distinguished based on their texture, crystal morphology and elemental composition. Both microsparitic layers are micrometre‐thick and are characterized by poorly co‐oriented calcite grains, but differ in their composition. Type 1 is depleted in magnesium but enriched in detrital elements such as silicon and aluminium, likely originating from the trapping and binding of detrital sediments on microbial mats during rainy seasons. In contrast, type 2 is enriched in magnesium but devoid of detrital elements, interpreted to have formed by the precipitation of calcium carbonate during dry seasons. The crystalline layers comprise fan‐shaped calcite crystals (ca 500 μm in length) with radiating internal structures, with their c‐axes oriented perpendicular to the stromatolite layers. These structures resemble those observed in some modern freshwater stromatolites, which are interpreted as imprints of cyanobacterial fascicules. While the cyclic occurrence of types 1 and 2 microsparitic layers might imply annual seasonal cycles, the less frequent crystalline layers are interpreted as a result of environmental changes occurring every 27 to 30 years. This is the first study to apply Electron Backscatter Diffraction to stromatolites, showcasing its potential in unravelling both the formative and diagenetic processes of ancient stromatolites. [ABSTRACT FROM AUTHOR]

On the rising demand for eco‐friendly refractories, reducing the use of likely toxic magnesia‐chromium aggregates remains a challenge. Previous studies by some of the authors have proposed Cr‐free alternative compositions, although the morphology of the spinel precipitates has varied across the different suggested systems. The mechanisms involved in the formation of these distinct morphologies were unclear and, therefore, are the focus of this work. In all compositions, SEM/electron backscatter diffraction revealed cube–cube orientation relationships between matrix and precipitates, indicating that their formation is influenced by the lattice parameter misfit (δ), which was measured using synchrotron X‐ray diffraction. It could be concluded that coarser and spherical precipitates form to minimize their surface‐to‐volume ratio in compositions with high absolute δ‐values. Conversely, low‐misfit systems enable the spinel to form a 3D‐network. The potential use of this knowledge to tailor the microstructure of novel compositions was demonstrated by a small Nb2O5 addition into one of the proposed compositions. [ABSTRACT FROM AUTHOR]

Petrologic investigation of the El Ali IAB iron meteorite (Somalia) revealed three new minerals: elaliite [ F e 8 2 + Fe3+(PO4)O8, IMA 2022-087], elkinstantonite [Fe4(PO4)2O, IMA 2022-088], and olsenite [KFe4(PO4)3, IMA 2022-100]. The name elaliite recognizes the occurrence of this mineral within the El Ali meteorite, originally located at 4° 17′ 17″N, 44° 53′ 54″E. Elkinstantonite is named after Linda (Lindy) Elkins-Tanton (b. 1965), a planetary scientist and professor in the School of Earth and Space Exploration at Arizona State University. The name olsenite is in honor of Edward J. Olsen (1927–2020), the former Curator of Mineralogy and Meteorites at the Field Museum of Natural History in Chicago (1960–1991). The new minerals and their names have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association. The holotype specimens of elaliite, elkinstantonite, and olsenite consist of the polished block mount with accession number MET11814/2-1/EP1 deposited in the University of Alberta Meteorite Collection. Elaliite, elkinstantonite, and olsenite occur along with wüstite, troilite, sarcopside, and Ca-bearing graftonite within inclusions in the iron-nickel metal (kamacite, 9.4 wt% Ni) that makes up the bulk of the El Ali sample. The empirical formulas determined by electron probe microanalysis for elaliite, elkinstantonite, and olsenite are: ( F e 7.943 2 + F e 1.020 3 + Cr0.010Ni0.006Ca0.004Mn0.004)Σ8.987(P0.932Si0.077S0.005)Σ1.014O12,( F e 3.947 2 + Mn0.016Ni0.003Ca0.001Cr0.001)Σ3.968(P1.986Si0.014S0.013)Σ2.013O9, and (K0.820Na0.135Ca0.004)Σ0.959(Fe3.829Mn0.050)Σ3.879(P2.972S0.058Si0.017)Σ3.047O12, respectively. Electron backscatter diffraction was used to confirm the crystal structures of the three new minerals. Raman spectra for all three minerals are also presented. [ABSTRACT FROM AUTHOR]

The thermal expansion coefficient (TEC) mismatch between the cathode and electrolyte presents significant challenge to the thermo-mechanical stability of commercial solid oxide fuel cells (SOFCs). Here a thermal expansion offset composite cathode designated as Ba 0.5 Sr 0.5 FeO 3-δ (BSF)-xNdMnO 3-δ (NM) (x = 0–40 wt%) is developed to address this issue. For the first time, the phase boundary between heterogeneous oxides and the grain size of composite cathode are quantitatively studied with the electron backscatter diffraction (EBSD) technology. For x = 20 wt%, the TEC of cathode decreases by 41 % while the peeling strength of cathode/electrolyte interface increases by 87 %. The highest peak power density (PPD) is achieved for BSF-20NM cathode (1266 mW cm−2 at 650 °C), which is 81 % higher than that for BSF one. Meanwhile, markedly enhanced long-term and thermal cycling stability is obtained. The comprehensive results suggest that both the increased TPB length by enhanced cathode/electrolyte bonding and grain refinement of composite cathode should be responsible for the markedly improved performance and stability. [ABSTRACT FROM AUTHOR]

In this paper, a crystal plasticity finite element method (CPFEM), considering the grain morphology and orientation, as well as the dislocation density, is used to research the tensile deformation behavior of GH4169 based on Electron Backscatter Diffraction (EBSD). The stress, plastic strain, and dislocation density distributions are obtained for different levels of deformation. Results show that the stress, plastic strain, and dislocation density exhibit obvious heterogeneous plastic deformation, and stress concentration and dislocation pileup mainly occurs near grain boundaries. The initial dislocation density mainly affects the stress–strain curve of the material, and it can obviously effect the yield strength but cannot influence the hardening ability of the material. The total dislocation density increases with plastic strain. However, the texture evolution has no evident change with increasing plastic strain, except for the increase of texture content in Cube (001)[100]. [ABSTRACT FROM AUTHOR]

Al-Mg alloys are characterized by permanent solid solution hardening and can additionally be work-hardened. The high mechanical properties of Al-Mg alloys with above-standard Mg content obtained after plastic deformation processes decrease over time. The addition of minor alloying elements like Er or Zr is an alternative method to improve the durability of mechanical properties and increase the strength of Al-Mg alloys due to densely and evenly distributed dispersoids being formed. In this paper, Al-Mg alloys with above-standard Mg content (7 wt.%) and Zr and Er micro-alloying elements and their influence on the microstructure and durability of the mechanical properties were examined. The cast ingots of AlMg7 alloys were characterized by a smooth surface without cracks. The plastic deformation process in a static compression test resulted in an about 60 HBW increase in the Brinell hardness of all the deformed alloys relative to casting. It was revealed that the addition of Er and Zr significantly improved the mechanical properties and durability of the mechanical properties of the Al-Mg after annealing. The addition of Er or Zr slightly restrained the decrease in the Brinell hardness after annealing but did not inhibit it. [ABSTRACT FROM AUTHOR]

Sphalerite (ZnS) is a sulfide found in a large variety of ore deposits and is frequently hosted in metamorphic terranes that have undergone deformation and related recrystallization. However, the deformation mechanisms of sphalerite are still poorly understood because recrystallization evidence is barely visible under an optical microscope and may reflect complex and frequently multistage mechanisms. Furthermore, sphalerite may host up to a few thousands of parts per million of critical metals such as gallium (Ga), germanium (Ge), and indium (In). Metamorphic conditions and dynamic recrystallization may have induced local or total redistribution of these elements. Modern techniques such as electron backscattered diffraction analyses (EBSD) and laser-induced breakdown spectroscopy (LIBS) applied on sphalerite allow for the examination of grain boundaries, crystal-plastic deformation, and internal chemical diffusion, which classically reflect active deformation mechanisms. In this study, a microstructural and in situ chemical comparison between four sphalerite types (types 1, 2, 3, and 4) has been made for the first time. The four sphalerite types present different deformation imprints, although they are hosted in a similar geological setting: the Pyrenean Axial Zone and the Montagne Noire Variscan massifs (France). Based on EBSD and LIBS mapping, we describe two regional sphalerite growth stages composed of dark red crystals with polygonal shape (type 1, Bentaillou-Liat deposit) and light- to dark-brown euhedral crystals (type 3, Saint Salvy deposit). New investigation at microscale on sphalerite grains from the Saint-Salvy deposit shows late Cu-Ge-Ga enrichment not only in specific sector zonings but also along grain boundaries, growing crystal edges, and in low-angle misorientations or twin boundaries. Following a deformation event that probably occurred during the Pyrenean-Alpine orogeny, these two sphalerite mineralizations have both endured plastic deformation in a dislocation creep regime and dynamically recovered by subgrain rotation (SGR) mechanism. Two mechanisms of Cu-Ga-Ge spatial redistribution are observed and are key processes for the crystallization of Cu-Ga-Ge-rich minerals in sphalerite veins. The first mechanism involved the in situ redistribution of Cu-Ga-Ge contents from a pre-existing concentration in the sphalerite lattice (type 3, Arre deposit), creating Ge-sulfides (briartite), probably during Pyrenean-Alpine orogeny. Formation of this type of Ge-mineral may be related to solid-state diffusion processes. The second mechanism is associated with the circulation of a Cu-Ga-Ge-rich fluid in surrounding rocks. In the pre-existing polygonal sphalerite from Late-Variscan veins (type 2, Pale Bidau deposit), millimeter-size bands of small (<50 μm), recrystallized sphalerite grains are locally observed. Those domains contain inclusions of Cu (chalcopyrite) and Ga and Ge minerals (brunogeierite, carboirite). Fluid-induced diffusion in the polygonal sphalerite aggregates may occur with superimposed dynamic recrystallization, such as the Late-Variscan veins (type 2, Pale Bidau-type). During post-Variscan time, this fluid enriched in Cu-Ga-Ge largely circulated in the upper-crust of this Variscan terrane. This study highlights the key importance of coupled textural (EBSD) and in situ chemical analyses (LIBS) of diverse sphalerite types at a regional scale to indirectly unravel the origin of vein mineralization, and their related critical metal distribution. [ABSTRACT FROM AUTHOR]

Pure titanium due to its high corrosion resistance, low stiffness and good mechanical properties is commonly used in medicine for orthopaedic applications. However, its material properties (especially in the case of α -titanium) require a further enhancement to fulfil its role. The thermoplastic deformation in mid-temperature is proposed as a method for microstructure improvement. Titanium samples were compressed in different temperatures and strain rates to determine the best conditions for grain fragmentation—the main factor responsible for strength and hardness increase. The thermoplastic stress–strain curves were registered. Then microstructure observations and electron backscatter analysis were performed on the chosen samples. Finally, mechanical response of the previously deformed material was obtained in room temperature compression tests. A significant grain fragmentation was recorded for the material deformed in 400 ∘ C , at 0.1/s and 1/s strain rates. Desirable results were also noticed for the deformation performed at 500–600 ∘ C . However, high temperatures (700–800 ∘ C ) and strain rates (10/s) resulted in dynamic recrystallization, causing undesirable grain growth. An increase in hardness was observed in all cases, with higher values recorded in lower deformation temperatures. Room temperature compression tests revealed slight increase of ductility. [ABSTRACT FROM AUTHOR]

This study explores a novel approach to quenching and partitioning (Q&P) heat treatment applied to AISI 9260 spring steel, comprising Fe-0.65C-1.58Mn-1.05Si-0.41Cr (wt.%). Our research focuses on balancing strength and ductility through optimized Q&P pathways, leading to a diverse microstructure that includes martensite, bainite, carbide, and retained austenite. Advanced X-ray diffraction and scanning electron microscopy techniques were employed to analyze the complexities of this microstructure. A key aspect of this study is the precise control of partitioning temperature and time, crucial for modulating lattice distortion and dislocation density within martensitic and bainitic structures. Optimal partitioning temperature promotes carbon distribution into austenite, tempering lattice distortions, and dislocation densities. Concurrently, carbide precipitation and segregation contribute to the refinement of the bainite phase. The sample quenched at 125 °C and partitioned at 350 °C (Q&P-125/350) demonstrates notable mechanical properties: a yield strength of 950 ± 15 MPa, an ultimate tensile strength of 1710 ± 15 MPa, and an elongation of approximately 9.7%. These results are partly attributed to the effect of silicon in preventing cementite coarsening and the effective distribution of carbide. Our findings highlight the potential of Q&P heat treatment in developing tailored microstructures with enhanced mechanical properties in steel, without relying on costly alloying elements. This approach presents new avenues for the design and application of high-performance materials. [ABSTRACT FROM AUTHOR]

This study delves into the microstructure and mechanical properties of a dissimilar metal weld (DMW) joining Incoloy 800HT and P91 steel. The P91 was buttered with Inconel 82 (ERNiCr-3) filler layers, and the final DMW weld was fabricated using Inconel 617 (ERNiCrCoMo-1) filler. Weld interface regions were characterized using electron backscatter diffraction (EBSD) and scanning electron microscopy. EBSD uncovered unique microstructural characteristics across the DMW. Extensive investigation was conducted on the heat-affected zone (HAZ) of Incoloy 800HT, revealing a consistently stable austenitic microstructure characterized by random grain orientations. Nevertheless, the weld fusion zone (WFZ) exhibits an intricate microstructure characterized by dendrites that extend into packets. The WFZ and the buttering layer interaction exhibited a predominantly face-centered cubic (FCC) structure. Recrystallization was indicated in this region. During tensile testing, the DMW specimens experienced failures at different locations and exhibited varying mechanical properties. A standard specimen made of Incoloy 800HT base metal experienced failure during welding. The DMW exhibited a maximum ultimate tensile strength (UTS) of 671 MPa and a yield strength (YS) of 234 MPa. The buttering process helped avoid the post-weld heat treatment to a certain extent. A maximum of 98 ± 5 J Charpy impact toughness was observed in the WFZ of the DMW failing in a complete ductile mode. [ABSTRACT FROM AUTHOR]

Textured microstructures and anisotropic properties are key factors for the optimization of magnetic materials. Only for high texture grades can the remanence Jr and the maximum energy product (BH)max be maximized. In additive manufacturing such as laser powder bed fusion (PBF-LB), methods to achieve texture have to be developed. In this work, anisotropic (CoCuFeZr)17Sm2 sintered magnets have been used as a substrate in experiments featuring single laser tracks to study the relationships between crystallographic orientation of the substrate grains and crystallographic orientation of grain growth in the melt-pool. The <0001> crystal direction (c-axis) of the substrate has been systematically varied with respect to the orientation of the laser scan track on the specimen surface. Crystallographic orientations of the melt-pool and the substrate have been analyzed using electron backscatter diffraction (EBSD). It is found that if the c-axis is oriented perpendicular to the temperature gradient in the melt-pool, grains grow with orientation similar to that of the substrate grain. If the c-axis and the temperature gradient are oriented in the same direction, the grains grow with high misorientation to the substrate. The highest anisotropy in the melt-pool is achieved when the substrate's c-axis is oriented along the laser scan track. Under these conditions, 98.7% of the melt-pool area shows a misorientation <45° compared to the substrate orientation. The texture grade of the melt-pool area is comparable to that of the substrate magnet, at 91.8% and 92.2%, respectively. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) alloys with long-period stacking ordered (LPSO) phases are receiving increasing interest because of their excellent mechanical performance. The close similarity in atomic stacking sequences between different LPSO polytypes and Mg lattice often leads to ambiguous indexing in electron backscatter diffraction (EBSD), a commonly used material characterization technique. Instead of the Hough transformation approach used in commercial software, an alternative indexing approach, which can catch subtle differences by matching experimental patterns with simulated ones, is explored in this study. Our results, showing ~94% of mapping data being correctly indexed as the target phase, 14H LPSO, demonstrate the capability of not only resolving the LPSO phases but also distinguishing different LPSO polytypes. This approach offers a valuable, if not unique, solution for the microscale characterization of LPSO phases, enabling precise microstructure tuning to further promote the mechanical properties of Mg alloys. [ABSTRACT FROM AUTHOR]

Glass substrate, a new type of substrate with excellent mechanical and electrical properties of glass itself, has great potential to become an ideal platform for heterogeneous integration in chiplet systems for high-performance computing applications. The residual stress of the metal layer generated on the glass surface during the electroplating process is one of the major bottlenecks of glass packaging technologies, resulting in glass-metal layer delamination and glass breakage. This paper demonstrated for the first time a method to regulate the residual stress by manipulating the nanotwin directions of the electroplated Cu. The experimental results show that nanotwins with three different directions (non-directional, vertical, and horizontal) can be manipulated by controlling electroplating conditions (concentration of Cl− and gelatin, stirring speed). The orientations of non-directional, vertical, and horizontal nanotwinned Cu are non-oriented, 110 and 111, respectively. After electroplating, the 111-oriented nanotwinned Cu has the smallest residual stress (39.7 MPa). Annealing can significantly reduce the residual stress of nanotwinned Cu, which has been attributed to the decrease in the geometric necessity dislocation density. 110-oriented nanotwinned Cu had drastic recrystallization, while 111-oriented nanotwinned Cu and non-oriented nanotwinned Cu had only slight recrystallization. After annealing, the residual stress of 111-nt-Cu remains the lowest (29.1 MPa). [ABSTRACT FROM AUTHOR]

Large electron backscatter diffraction area maps were used in the present work to characterize the microstructure and texture near the horizontal and vertical keyhole peripheries of the AA5182 alloy after friction stir spot welding. The findings demonstrate that the horizontal keyhole peripheric comprises a stirred zone (SZ) and a thermo-mechanically affected zone (TMAZ). The SZ started 300 µm away from the keyhole center and became thicker with increasing horizontal distance. The texture gradually changed from shear A 1 ∗ / A 2 ∗ components at the SZ to rolling cube, goss, and brass components at the TMAZ. The vertical keyhole peripheric is mainly composed of SZ with an onion ring grain structure and is dominated by the C shear component. [ABSTRACT FROM AUTHOR]

Monel K500 is a high strength, precipitation hardenable, nickel-copper alloy with additions of Al and Ti, having excellent corrosion resistance and ignition resistance to high pressure gaseous oxygen. However, this alloy is highly sensitive to hot workability and is crack prone during hot deformation. This study investigates the effect of hot workability parameters such as temperature, strain rate, and overall strain on the microstructure evolution. The hot deformability of this alloy was studied using isothermal hot compression tests in the temperature range of 850 °C to 1150 °C and at strain rates ranging from 10− 3 to 10 s− 1, using a Gleeble 3800 thermo-mechanical simulator. The flow behaviour was analysed using stress-strain and strain hardening plots. Initial microstructure of the material has as-cast dendritic structure, while microstructural analysis of hot deformed samples revealed gradual reconstitution with increasing temperature and decreasing strain rate. Hot deformed samples showed traces of recrystallized grains and carbides across the matrix at high temperatures and low strain rates. EBSD GROD mapping further elucidates the variation of microstructural features with variation of strain rate. In accordance with the Ziegler instability criterion, processing maps were constructed for a true strain of 0.65, encompassing deformation temperatures between 850 °C and 1150 °C, and strain rates ranging from 0.001 to 10 s− 1. Through an examination of strain rate sensitivity map, processing map and analysis of deformation activation energy, both undesirable (unstable) and potentially favourable (stable) hot deformation parameters were identified. Instability regions in the processing maps were validated with the microstructural features of deformed samples of cast Monel K500 alloy. [ABSTRACT FROM AUTHOR]

The mechanical behaviors of CL65 wheel rim material from tread to depth under different temperatures (25-600 °C) and strain rates (0.001-7000 s−1) were investigated by utilizing quasi-static tensile and split Hopkinson pressure bar tests. The Johnson–Cook model of CL65 wheel steel was fitted, and the corresponding dynamic mechanics of wheel steel was discussed. The results show that the stress–strain curves of CL65 wheel rim steel were strain rate dependent and temperature dependent that the stress increased with the increase in strain rate and decreased with the rise of test temperature. With the elevated distance from the tread, the pearlite grain size, interlamellar spacing, and volume fraction of pre-eutectoid ferrite increased, resulting in an increase in ductility of quasi-static tensile and a decrease in the strength of the materials. In addition, the thin cementite layers showed more substantial toughness than the thick cementite layers. During the plastic deformation, high temperature promoted the fragmentation and dissolution of cementite lamellae, significantly impacting the thin cementite layer more than the thick cementite, which reduced the hindrance of dislocation movement during the plastic deformation, leading to weaker strain rate sensitivity and stronger temperature sensitivity in the material near the wheel tread (Zone 1) than in the deep material (Zone 2 and Zone 3). [ABSTRACT FROM AUTHOR]

In this manuscript, I introduce a convenient method to convert the Euler angles (complete crystal orientations) obtained with EBSD (electron back-scattered diffraction) to the azimuth and inclination angle of crystallographic axes to reconstruct the pole figures. This method, which is subsequently coupled with the rotation of the pole figures, is particularly useful for the analyses of quartz c-axis fabrics in the deformed rocks, where the foliation and/or lineation is not clear or unknown. Although we arbitrarily choose the sample coordinates (Xs-Ys-Zs) in such cases, it is often possible that we can rotate the quartz c-axis pole figures so that they will exhibit a well-defined intrinsic symmetry in the rotated sample frame. The rotated XsYs-plane and Xs-direction can be now called the foliation and lineation, respectively, inversely defined by the quartz c-axis fabrics. On the other hand, the foliation and lineation clearly defined by the shape-preferred orientations (SPOs) of platy or columnar minerals can be oblique to those defined by the quartz c-axis fabrics. In this case, the former foliation and lineation could represent the total strain, while the latter ones could represent the last incremental strain, indicating triclinic deformation symmetry (e.g., triclinic transpression). [ABSTRACT FROM AUTHOR]

This study explores the impact of microstructural features on fatigue crack initiation in poly‐crystalline materials, emphasizing hydrogen‐induced complexities. Grain anisotropy, misorientations, grain size variations, and elastic–plastic inhomogeneities concentrate stress at grain boundaries, making them susceptible to crack initiation during fatigue loading. The presence of hydrogen compounds this process, due to complications of characterization of local hydrogen content and activating embrittling mechanisms. Building upon a model for nickel, this research investigates 316L austenitic stainless steel specimens with varying grain sizes, both uncharged and hydrogen‐charged. In situ low‐cycle fatigue loading experiments establish correlations between fatigue crack initiation and microstructural features. The study reveals specific combinations of features crucial in the initiation process, undergoing alterations in the presence of hydrogen. A proposed qualitative model links microstructural features with accumulated plastic shear strain during fatigue and prevalent hydrogen embrittlement mechanisms like hydrogen‐enhanced local plasticity and hydrogen‐enhanced decohesion. Highlights: The effects of hydrogen on fatigue crack initiation (FCI) sites in stainless steel 316L are studied.Two different grain sizes were analyzed by in‐situ scanning electron microscopy (SEM) and electron back‐scattered diffraction (EBSD) and high‐resolution digital image correlation (HR‐DIC).Hydrogen‐assisted FCI is correlated with initial features of the microstructure.A model is proposed linking FCI with microstructure and accumulated plastic shear strain. [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]

The additive manufacturing technique has emerged as a prominent primary manufacturing technique on a global scale. Technological advances in the metal additive manufacturing process have made it a potentially revolutionary novel method to manufacture complicated structures in aerospace, energy, and construction industries. In the present study, Hastelloy C-22 thin-wall part was developed using a mechanized pulsed mode wire arc additive manufacturing (WAAM) process. The microstructural and mechanical strength characterization of the additively developed thin-wall part was investigated in the cross and transverse sections. The metallographic structure investigation of both sections revealed the existence of equiaxed, cellular, and elongated dendrites in the top, middle, and bottom regions, respectively. The scanning electron microscope (SEM) with energy dispersive spectrum (EDS) assessment revealed a increases in the concentration of Mo in the inter-dendritic regions of the thin-wall section, in contrast to the dendritic core regions. The pulsed mode process uses an increased cooling rate, which reduces elemental segregation, encourages a improved microstructure, and enhances better mechanical performance. In the electron-backscattered diffraction analysis, the mean grain size is 139.29 µm in the cross-section and 109.30 µm in the transverse section. The volume proportion of higher-angle grain boundaries (HAGBs) is more significant than that of lower-angle grain boundaries (LAGBs), increasing mechanical characteristics. The maximum Vickers microhardness values are attained in the transverse section, with measurements of 311 HV, 304 HV, and 300 HV at the top, middle, and bottom, respectively. Similarly, the mechanical strength also increased in the top region of the transverse section, with an ultimate tensile strength (UTS) of 745 MPa ± 2.80. The fluctuation in mechanical strength can be related to the presence of microstructural heterogeneity. The present research examines the correlation between the microstructural and mechanical properties of a Hastelloy C-22 developed by robust wire arc additive manufactured. [ABSTRACT FROM AUTHOR]

Scanning electron microscopy (SEM) enables microstructure characterization at multi-scale, having potential to quantify strain distribution across multiple fields of view (FOVs) and exploring coordinated relationships among the deformations of multi-scale microstructures. Optimizing distribution of multi-scale speckles is crucial for achieving high precision and efficiency in digital image correlation (DIC) computations. In this work, a multi-scale strain measurement method is proposed for in-situ SEM mechanical experiments, which relies on an uncomplicated multi-scale speckle preparation method. Multi-scale speckle preparation can be achieved by the combination of spin-coating and magnetron sputtering. By using micro- and macro-speckle, multi-scale strain calculations can be achieved during the in-situ SEM mechanical loading. The InSn macro-speckle is composed of controllable-sized InSn nanoscale speckles, ensuring that the accuracy of DIC measurements in the microscopic regions are not compromised by the coverage of macro-speckles in the testing region. In regions covered exclusively by SiO2 nano-speckles, in-situ SEM mechanical loading allows for the acquisition of high-resolution DIC (HR-DIC) and electron backscatter diffraction (EBSD) data from the same region and under the same deformation state. Experiments are conducted to illustrate the functionality and utility of the multi-scale speckles. Such experimental analyses offer an opportunity to further explore multi-scale strain heterogeneity in some advanced structural materials and provide reliable experimental verification for material mechanics simulations.

Near-β titanium alloys have shown low Young's modulus and good strength, making them excellent implant candidates. However, their processing using thermomechanical routes in single phase β region results in heterogeneous microstructures due to high content alloying elements and consequent slow diffusion-controlled processes such as dynamic recovery. This study investigates the deformation behaviour of a Ti–15Mo alloy through hot compression experiments using a Gleeble ® 3800 device in the single β domain at strain rates from 0.01 s−1 to 10 s−1, reaching final strains of 0.50 and 0.85 followed by immediate water quench. The findings show that the material presents a low strain rate sensitivity. The flow curves show significant strain hardening before reaching a steady-state regime, particularly at high strain rates. The strain hardening exponent calculations support the effect of molybdenum on retarding softening mechanisms such as dynamic recovery. Electron backscatter diffraction (EBSD) measurements of deformed samples revealed that dynamic recovery is the primary restoration mechanism, with continuous and geometric dynamic recrystallisation evidence. Due to the slow restoration process, we observe the subgrain formation for different deformation parameters. Therefore, we introduced an EBSD-based method to quantify dynamic recovery and subgrain size. We concluded that for a given deformation, the areas of dynamically recovered and recrystallised regions decrease with increasing strain rate and decreasing temperature, exhibiting negligible variation at higher strain rates.

In this study, the thermal deformation behavior of Cu–Ti–Zr(-Mg) alloys were investigated by Gleeble-1500D. The two alloys were deformed at 700–900 °C with 0.003–10 s−1 strain rate. The intrinsic equations of the two alloys were constructed and calculated thermal activation energies, which indicates that it is improved from 325.67 kJ/mol to 344.03 kJ/mol after Mg addition. The result showed that the hot working area of Cu–Ti–Zr alloy is greatly extended after Mg addition, and rheological instability area is reduced. The morphology of the alloys was observed to analyze thermal behavior. It revealed that Mg elements inhibited the occurrence of dynamic recrystallization and shifted the texture types in the alloys by characterization of EBSD. TEM results showed that the phases during hot deformation in Cu–Ti–Zr–Mg are Cu4Ti and Cu10Zr7, which are in a semi-coherent relationship with the Cu matrix.

Following the advent of three-dimensional (3D) printing technology, multi-material 3D printing has garnered significant attention due to its potential to enhance the flexibility and development of high-performance 3D printing materials. This study investigated the application of explosive welding to create multi-material 3D printed structures. Specifically, we explored the use of direct and interlayer explosive welding to fabricate SLM-AlSi10Mg/SLM-SUS316L explosive composites with the aim of further improving material properties. Our primary objective was to explore the unique interfaces and mechanical characteristics of 3D printed materials subjected to explosive impact loading. This study provides a new idea of 3D printing multi-materials, which is of great significance for the development of both explosive welding and 3D printing. The results demonstrated the feasibility of using explosive welding to create multi-material composites from 3D printed metals, including both direct and interlayer welding of SLM-AlSi10Mg/SLM-SUS316L. Interlayer welding exhibited superior mechanical performance compared to direct welding, with a 70%–250% increase in strength observed in the macro tensile shear test. Additionally, samples fabricated with a 40 mm explosive thickness displayed more stable and exceptional performance in the micro tensile test. Corrosion testing and X-ray computed tomography (XCT) analysis were employed to investigate the distribution of pores within the 3D printed materials.

A crystal plasticity model based on Electron Backscatter Diffraction (EBSD) experimental data has been developed to simulate the tensile behavior of additively manufactured TiAl alloys at various temperatures. To accurately capture the activity of different slip systems and their contribution to the material's plasticity, multiple slip systems across different phases are considered. The validity of the model is verified by comparing the simulation results, such as microscopic properties, with experimental and test data. Additionally, a continuous damage model is incorporated to analyze the damage behavior of additively manufactured TiAl alloys at different temperatures. Compared to experimental data, the crystal plasticity model incorporating damage effectively simulates the tensile failure behavior of TiAl alloys across a range of temperatures.

Based on the microstructure analysis, the present research investigated the influence of various austenitizing conditions on the transformation behavior of intermetallic compound particles, i.e. η-Ni3Ti, and the reversed austenite during ageing treatment in Ti–Mo maraging stainless steel, as well as the related mechanical properties. The results revealed numerous tiny rod-like intermetallic compound particles, i.e. η-Ni3Ti, having a Burgers orientation relationship, i.e., {101}α′//{0001}η ; α′//η, with the martensite matrix, as well as blocky, lath, and granular reversed austenite of various sizes distributed within the tempered martensite matrix. Regardless of the austenitizing treatment condition, more reversed austenite was found in the samples aged at 520 °C than in those aged at 640 °C. Although this finding was not consistent with the Thermo-Calc predictions, it should be associated with the thermal stability of reversed austenite at different ageing temperatures. In other words, the greater amount of reversed austenite that formed at 640 °C did not remain at room temperature due to secondary martensite transformation during cooling, as was verified by EBSD analysis.

Copper as one of the major electronic metals will experience electric current stressing during electronics application. The study comprehensively investigated microhardness and electrical resistivity variations of copper under current stressing at current densities 1.4 x 104 and 1.7 × 104 A/cm2 for up to 8 h. The variations in these properties were correlated with dislocation density and twin fraction. The dislocation density and twin fraction were estimated, respectively, with high resolution transmission electron microscope and Electron Backscatter Diffraction. The twin boundary acts as obstacle to dislocation movement as revealed by high resolution transmission electron microscopy. The twin boundary predominates over dislocation in governing the microhardness and electrical resistivity of copper under current stressing.

An enhancement in fatigue life for ferrite–pearlite low-carbon steel (LCS) at high temperature (HT) has been discovered, where it increased from 190,873 cycles at room temperature (RT) to 10,000,000 cycles at 400 °C under the same stress conditions. To understand the mechanism behind this phenomenon, the evolution of microstructure and dislocation density during fatigue tests was comprehensively investigated. High-power X-ray diffraction (XRD) was employed to analyze the evolution of total dislocation density, while Electron Backscatter Diffraction (EBSD) and High-Resolution EBSD (HR-EBSD) were conducted to reveal the evolutions of kernel average misorientation (KAM), geometrically necessary dislocations (GND) and elastic strains. Results indicate that the enhancement was attributed to the dynamic strain aging (DSA) effect above the upper temperature limit, where serration and jerky flow disappeared but hindrance of dislocations persisted. Due to the DSA effect, periods of increase and decrease in the total dislocations were observed during HT fatigue tests, and the fraction of screw dislocations increased continuously, caused by viscous movement of the screw dislocations. Furthermore, the increased fraction of screw dislocations resulted in a lower energy configuration, reducing slip traces on sample surfaces and preventing fatigue-crack initiation. [ABSTRACT FROM AUTHOR]

Copyright of Iron Steel Vanadium Titanium is the property of Iron Steel Vanadium Titanium Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To develop new criteria to distinguish different crystal nucleation mechanisms in silicate melts, we performed crystallization experiments using a synthetic hydrous (2 wt% H2O) trachybasalt and combined three-dimensional information from synchrotron X-ray computed microtomography with two-dimensional mapping of crystallographic orientation relationships (CORs) using electron backscatter diffraction. Crystallization experiments were performed at 400 MPa by cooling the melt from 1300 °C to resting temperatures of 1150 and 1100 °C and maintaining isothermal conditions for 30 min and 8 h. Three distinct titanomagnetite (Tmt) populations formed: (1) skeletal crystals, isolated or partially embedded in clinopyroxene (Cpx); (2) anhedral crystals, always attached to Cpx; (3) flattened needle-shaped crystals, embedded in Cpx. These morphologically different Tmt populations formed in response to one cooling event, with varying nucleation mechanisms and at different undercooling conditions. The clustered three-dimensional distribution of population 2 and 3 Tmt grains and the high proportion of Tmt-Cpx interfaces sharing CORs indicate that these Tmt grains heterogeneously nucleated on Cpx. The near-random three-dimensional distribution of (often isolated) population 1 Tmt grains, together with the low proportion of Tmt-Cpx interfaces sharing CORs, imply their isolated, possibly homogeneous nucleation, potentially followed by heterogeneous nucleation of Cpx on population 1 Tmt. Heterogeneous nucleation in slightly to moderately undercooled magmas should affect the sequence of crystallization as well as morphology and clustering of crystals, which may actively contribute to the variation of rheological parameters like viscosity. Finally, observed intra- and inter-sample variations in Tmt-Cpx COR frequencies indicate the potential for this parameter to record further petrological information. [ABSTRACT FROM AUTHOR]

For permanent magnetic materials, anisotropic microstructures are crucial for maximizing remanence Jr and maximum energy product (BH)max. This also applies to additive manufacturing processes such as laser powder bed fusion (PBF-LB). In PBF-LB processing, the solidification behavior is determined by the crystal structure of the material, the substrate, and the melt-pool morphology, resulting from the laser power PL and scanning speed vs. To study the impact of these parameters on the textured growth of grains in the melt-pool, experiments were conducted using single laser tracks on (CoCuFeZr)17Sm2 sintered magnets. A method was developed to quantify this grain shape anisotropy from electron backscatter diffraction (EBSD) analysis. For all grains in the melt-pool, the grain shape aspect ratio (GSAR) is calculated to distinguish columnar (GSAR < 0.5) and equiaxed (GSAR > 0.5) grains. For columnar grains, the grain shape orientation (GSO) is determined. The GSO represents the preferred growth direction of each grain. This method can also be used to reconstruct the temperature gradients present during solidification in the melt-pool. A dependence of the melt-pool aspect ratio (depth/width) on energy input was observed, where increasing energy input (increasing PL, decreasing vs) led to higher aspect ratios. For aspect ratios around 0.3, an optimum for directional columnar growth (93% area fraction) with predominantly vertical growth direction (mean angular deviation of 23.1° from vertical) was observed. The resulting crystallographic orientation is beyond the scope of this publication and will be investigated in future work. [ABSTRACT FROM AUTHOR]

In this study, 48 hot-rolling processing conditions were designed to investigate the influences of thermomechanical processing parameters on the recrystallization behavior and texture development. The hot-rolling experiments were conducted using the thermomechanical simulator Gleeble 3800 at temperatures of 275, 300, and 350 °C with strain rates of 5 and 90 s − 1 up to 60 and 85% reduction. The microstructure and texture analysis were measured by using the EBSD technique on a large area. Experimental results show that the Cube component maintains a volume fraction between 10% and 20%, below the 40% recrystallization fraction, but the volume fraction of Cube significantly increases between 20% and 50% above the 40% recrystallization fraction. However, the fractions of Rotated Cube (RC) and Goss components remain below 10%. [ABSTRACT FROM AUTHOR]

In this study, the creep deformation behavior of conditioning-treated Co-Cr-W-Ni-based cast superalloy with and without B and Zr additions was investigated using constant load creep tests conducted at temperatures of 700 °C (973 K) and 800 °C (1073 K) and stresses ranging from 200 to 400 MPa. For both alloys, secondary creep strains were analyzed in terms of minimum creep rate and activation energy. Also, modified Monkman–Grant relation was used to analyze the experimental data, and a good correlation between minimum creep rate and rupture time was observed. Creep results revealed that the samples with B and Zr additions exhibited remarkably higher creep strain and longer creep life for the same loading condition. The failure mechanism was investigated with scanning electron microscopy (SEM), and the results show that the alloy without additions exhibits a failure mechanism caused by nucleation and void coalescence within skeleton-type M23C6 carbides. In the case of the alloy with additions, it was caused by nucleation and growth of voids in the interface of the matrix and bulk M23C6 carbides. Finally, electron backscatter diffraction (EBSD) results unveiled that the matrix shows low creep-induced plastic strain in the case of the alloy without additions. While in the case of the alloy with additions, extended plastic strains are seen in the γ matrix that can be related to its higher creep strain, lower creep rate, and longer creep life. [ABSTRACT FROM AUTHOR]

In the multilayer thin-walled Inconel 625 alloy structures fabricated by the laser additive manufacturing (LAM) process, the poor plasticity of the interlaminar region often leads to structural fractures. In this paper, an oscillating LAM (O-LAM) technology using a transverse linear beam oscillation (LBO) process was proposed, and the effect of laser scanning speed on the forming accuracy, microstructure, crystallographic texture, and mechanical properties of interlaminar region was studied. The results show that the LBO process refined the grains and increased the number and length of high-angle grain boundaries in the interlaminar region. In addition, the LBO process with high laser scanning speed weakened the preferential orientation along the directions of laser scanning and deposition build-up. In particular, the dominant crystallographic textures of { 1 ¯ 10 } < 1 ¯ 1 ¯ 1 > and { 2 ¯ 21 } < 1 ¯ 1 ¯ 0 > in the interlaminar region were significantly reduced. The analysis of the Schmidt factor and the results of nano-indentation test show that the LBO process with high laser scanning speed reduced the stress concentration, and the elastic modulus and dislocation density in the interlaminar region. Therefore, the LBO process with high laser scanning speed can improve the plasticity and relieve the stress concentration of the interlaminar region, which is conducive to improving the overall mechanical properties of the Inconel 625 alloy multilayer thin-walled structure. [ABSTRACT FROM AUTHOR]

Mollusk shells protect the animals that form and inhabit them. They are composites of minerals and organics, with diverse mesostructures, including nacre, prismatic calcite, crossed‐lamellar aragonite, and foliated calcite. Twins, that is, crystals mirror symmetric with respect to their coherent interface, occurring as formation or deformation twins, are observed in all mollusk shell mesostructures but never within calcite prisms. Here, nanotwins and microwins within single calcite prisms are observed in different shells. Using Polarization‐dependent Imaging Contrast (PIC) mapping with 20–60 nm resolution, twins are observed to be 0.2–3 µm thick layers of differently oriented and colored crystals with respect to the main prism crystal. Multiple twins are interspersed with the prism crystal, parallel to one another, and similarly oriented. When comparing images of calcite prisms and twins obtained by PIC mapping and by Electron Back‐Scattered Diffraction (EBSD), the images correspond precisely. All twins are e‐twin types, with 127° angular distance between c‐axes. E‐twins are the most common deformation twins in geologic calcite, as also observed here in Carrara marble. Location of all twins near the outer surface of all shells and e‐twin type both suggest that twins within calcite prisms in mollusk shells result from deformation twinning. [ABSTRACT FROM AUTHOR]

In this article, the evolution of microstructural characteristics of selectively laser-melted AlSi10Mg alloy subjected to equal channel angular pressing (ECAP) is investigated. The microstructures were analyzed in detail using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission Kikuchi diffraction (TKD), and transmission electron microscopy (TEM). A heterogeneous ultrafine-grained microstructure was produced after one ECAP pass at 100 °C. This microstructure was composed of Al/Si cells and sub-micrometer grains. The grains were refined by conventional dislocation processes; however, evidence of dynamic recrystallization was also documented. Furthermore, it was revealed that the Al/Si cells contribute significantly to grain refinement. EBSD/TKD investigations showed that cell misorientation increased after ECAP processing, resulting in an increased fraction of grains with very low misorientation angles. [ABSTRACT FROM AUTHOR]

In this study, a comprehensive set of characterization techniques are employed to demonstrate that the cold spray deposition process can result in a significant increase in martensite in austenitic stainless steel. The lack of consensus in the literature on the formation of strain-induced martensite in cold spray can be attributed to the diverse processing conditions and measurement techniques used in different studies. In this work, EBSD, neutron diffraction, TEM imaging, and precession electron diffraction were used in combination to examine whether strain-induced martensite is formed during cold spray deposition of 304L stainless steel powder and to give further insight into possible mechanisms controlling this phenomenon. Cold spray was performed at both 350 °C and room temperature (25 °C) to investigate the effects of spray temperature on the martensite transformation. It is shown that the strain-induced martensite formation is significantly suppressed compared to that which would be expected for comparable levels of plastic strain at quasi-static strain rates. Additionally, the spray gas temperature is shown to directly impact the microstructure formed at the prior particle interface and the formation of dynamically recrystallized regions. [ABSTRACT FROM AUTHOR]

Zircon, with a chemical formula of ZrSiO4, is a widely used mineral for determining the crystallization age of igneous rocks. It is also used to constrain the timing of metamorphic events from its overgrowth or recrystallized domains. Furthermore, detrital zircon grains can provide information on the sedimentary provenance. Due to the trace amounts of uranium (parent) which decays into its daughter element (Pb), it is a prime geochronometer for the majority of magmatic and metamorphic rocks. With high-precision analytical instruments, such as TIMS, SIMS, and LA-ICP-MS, huge amounts of geochronological and trace element data from zircon have been generated around the globe to date. Target domains within zircon grains are analyzed to extract geochemical and geochronological records using spatially resolved techniques such as ion probes or laser ablation coupled with mass spectrometry. Before any such analysis, the zircon grains are examined for internal structures, growth zoning, and the presence of tiny inclusions. However, many researchers analyze multiple domains within single zircon grains for U-Pb isotope analysis with little regard for their internal structures, particularly crystallographic orientations. Hence, they may obtain mixed ages with variable discordance, leading to imprecise interpretation especially when the growth domains are not well-identified. Particularly, zircon grains that contain multi-growth domains or have local internal deformations within a single grain may not produce geologically meaningful age results if the analyses are conducted on mixed domains. This study presents a brief review on zircon geochronology, how to identify and visualize micro-deformations in metamorphic zircons through the EBSD analysis, and the effects of micro-deformation on age results. Examples from a case study conducted on zircons hosted in the Himalayan high-pressure eclogites are presented that show intra-grain plastically deformed domains and their effects on the corresponding age results. [ABSTRACT FROM AUTHOR]

Achieving superior properties in hot working demands the integration of constitutive modeling, precise microstructure control, and the rigorous identification of safe and efficient conditions. To address this, a powder metallurgy Al–Zn–Mg alloy underwent isothermal compression tests under conditions of 300–500 °C and 0.1–0.0001 s−1. The experimental outcomes indicate that the flow stress of the Al–Zn–Mg alloy exhibits dynamic recrystallization as the predominant softening mechanism observed across all investigated hot working parameters. An Arrhenius-type model integrated with strain was constructed to describe its hot working behavior. Establishing processing maps, while considering the effect of strain, facilitated the assessment of the workability of the Al–Zn–Mg alloy. Constructed processing maps suggest that recommended processing conditions fall within the range of 475–500 °C and 0.001–0.0001 s−1, revealing the presence of uniform equiaxed grains and recrystallized structures. Samples compressed at 300 °C/0.1 s−1 exhibited adiabatic shear bands and partial recrystallization, while microcracks were found in samples deformed at 400 °C/0.1 s−1 and 500 °C/01 s−1. The microstructural changes were analyzed using EBSD, employing various maps, including IPF, KAM, GOS, and GAM, to assess dislocation density, grain misorientation, and their correlation with recrystallization in relation to both strain rate and temperature. [ABSTRACT FROM AUTHOR]

Titanium is as strong as steel with less density. Therefore, titanium and its alloys are used in several engineering applications. The primary benefits of using titanium alloys in the production of high-performance components include their light weight, superior tensile strength and exceptional corrosion resistance. Titanium alloys have the capacity to keep their characteristics even at high temperatures. Because of their low density and capacity to withstand temperature extremes, these alloys are mostly utilised in airplanes, spacecraft and missiles. Many of the initiatives to save costs in the production of titanium components are based on additive manufacturing. This study aims to provide preliminary insight into the microstructural and mechanical behaviour of commercially pure grade-2 titanium (CP-Gr-2-Ti) structured wall fabricated by gas tungsten arc welding assisted layer-by-layer manufacturing (GTAW-assisted-LM). Ideal process variables were selected through the trial-and-error method. The vacuum chamber was used during fabrication to ensure that the wall was free of contamination. The anisotropy in the LM processed wall is studied with different orientations of tensile samples. The variation in the microstructure observed in LM processed wall was due to varying complex thermal cycles. The phase texture and grain nature of the wall was studied using pole figures and inverse pole figures. The LM-processed wall exhibits better mechanical properties compared to wrought alloys. The fractography revealed several morphologies indicating that the fractured samples were ductile. Hence, a piece of first-hand information and experience is gained in this research work. [ABSTRACT FROM AUTHOR]

Heterogeneous integration is a key driver within the field of advanced electronic packaging. The realization of tomorrow's highly integrated electronic systems depends on the combination and compatibility of various integration technologies at the same hierarchy level. The adoption of novel bonding technologies for a cost-effective realization of multi-chiplet systems is a key aspect. Cu nanowire (NW) interconnects exhibit distinct advantages in terms of their scalability down to a few micrometers, the resulting joint properties and moderate demands with respect to the surface preparation, and the cleanliness of the bonding environment. No solder or flux is required for the bonding process, but the NW bumps still can compensate low height differences. The bonding process can be carried out near room temperature under ambient conditions. We demonstrate the technological possibility to integrate the Cu-NWs for a bump processing scheme including the Cu seed etching on 300 mm wafer for the first time. This paper focuses on the microstructure evaluation and the shear test of the formed Cu-NW interconnects fabricated under ambient conditions within a few seconds. The microstructure analysis shows the intact bonded interconnects and reveals high-resolution details of Cu-NWs. The shear strength of the formed interconnects varies between 4.6 MPa and 90.5 MPa depending on the bonding and annealing conditions. Overall, the results of this study highlight the potential of Cu-NW interconnects for future 3D heterogeneous system integration. [ABSTRACT FROM AUTHOR]

This study explores the effects of tempering on the precipitation behavior and impact toughness of high-nickel steel. The specimens underwent double quenching at 870 °C and 770 °C, followed by tempering at various temperatures. Advanced characterization techniques including optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to elucidate precipitation phenomena. Additionally, electron backscatter diffraction (EBSD) was employed to assess the misorientation distribution after tempering. Charpy impact tests were performed on specimens tempered at different temperatures to evaluate their toughness. The findings reveal that with increasing tempering temperature, the fraction of low-angle grain boundaries decreases, which correlates positively with enhanced impact toughness. The results demonstrate that tempering at 580 °C optimizes the material's microstructure, achieving an impact toughness value of approximately 163 J. [ABSTRACT FROM AUTHOR]

SA508Gr.3Cl.2 steel is extensively employed in fabricating nuclear reactor facilities consisting of reactor pressure vessels and steam generators. The functional performance of components is affected by the properties of superficial layers, and the machining process is indispensable for the final forming. Hence, it is essential to modify and improve surface quality via the regulation of machining parameters. This paper presents a comprehensive investigation of the effects of high-speed face milling process on the surface modification of SA508Gr.3Cl.2 steel, with particular attention to surface topography, microstructure alteration, micro- and nano-hardness, and residual stresses under semi-finishing conditions. To control the machined surface integrity via regulating milling parameters, surface characteristics are compared under various milling speeds and feeds. Results indicate that the unwanted geometrical defects in the form of feed marks, plowing grooves, surface tearing, and side flow are inherited on the machined surface, and the surface roughness is maintained at a relatively lower level, up to Sa 0.822 μm and Sz 5.824 μm. In addition, the material dragging layers with different thicknesses between 4.1 and 8.5 μm are introduced into the regions near the machined surface, which are subjected to intense plastic activities, including dislocation proliferation, grain boundary deflection, grain refinement, and elongation. There is no evidence of white layer and phase transformation at the superficial layer of machined SA508Gr.3Cl.2 steel. Besides, the increased milling speed and feed are responsible for thicker plastic deformation layers and greater hardening depths and promote surface hardening. A cutting configuration with a higher milling speed and lower feed is recommended to obtain attractive component surfaces with fewer geometrical defects, lower roughness, lower tensile residual stresses, proper hardening, and no white layer and phase transformation. [ABSTRACT FROM AUTHOR]

The hot compression test of CrFeCoNiAl0.1 high entropy alloy at temperature range of 950-1100 °C and strain rates range of 0.001–1 s−1 was carried out by Gleeble−3500 thermal compression simulator. The characteristics of microstructure evolution of the studied alloy during hot deformation were studied by means of OM and EBSD. The Arrhenius-type constitutive equation was constructed, and the hot deformation activation energy was calculated to be 307.77 K J mol−1. The proportion of low angle grain boundaries is 10.2% at the condition of 1050 °C/0.01 s−1, and the complete dynamic recrystallization (DRX) occurs. The characteristic parameters are determined according to the relationship between the work hardening rate and the true stress, and the mathematical relationship between the critical conditions for DRX and Z parameters is obtained. The critical stress for DRX decreases with increasing temperatures and decreasing strain rates. The kinetic model of DRX is constructed by the Avrami equation. Higher temperature and lower strain rate were beneficial to the occurrence of DRX. Based on microstructure evolution, the DRX volume fraction model of CrFeCoNiAl0.1 high entropy alloy was verified, and the experimental results are close to the predicted results. The DRX volume fraction model can correctly predict the DRX behavior of CrFeCoNiAl0.1 high entropy alloy. [ABSTRACT FROM AUTHOR]

Palladium–platinum alloys were analysed by dynamic secondary ion mass spectrometry (SIMS) to investigate grain orientation effects that gave differences of up to 400% in the Pt/Pd count rate ratios, even within the same grain upon small rotations of a Pd sample with 1 wt% Pt. The sample had been homogenized by annealing, and the homogeneity was confirmed by X‐ray analysis in scanning electron microscopy (SEM). Grain orientations were determined by electron backscatter diffraction (EBSD). Crater depths were measured by white light interferometry (WLI). SEM images from the bottom of SIMS craters made in the same grain after small rotations around the sample surface normally showed different patterns of microfaceting for some rotation angles, probably exposing low‐index crystallographic planes. A complete understanding of the observed grain orientation effect is still lacking. However, factors such as ion mass, sputter rate, ion channelling, ion focusing, preferential sputtering, surface height, crater microfaceting and/or angle‐dependent sputtering seem to play a role. For these Pd–Pt alloys, the strong grain orientation effect adds another level of complexity when attempting to quantify concentrations and obtain depth profiles by SIMS. Without proper sampling and/or averaging, one could reach very wrong conclusions when comparing results from different samples. [ABSTRACT FROM AUTHOR]

The cast IN 713 C alloy is extensively used in the aerospace and automobile industries. Even with improved casting methods, the inhomogeneity in the microstructure is still inevitable and causes strain localizations during cyclic loading. So far, the effect of microstructural variables on the low cycle fatigue (LCF) deformation behavior of IN 713 C alloy has rarely been studied. In this study, IN 713 C alloy is LCF tested at 650°C and 750°C for strain amplitudes of 0.35% to 0.6%. The results showed that the deformation heterogeneity resulted from carbides, γ′ precipitates, and γ–γ′ eutectics distribution, governing the LCF failure micro‐mechanisms. The principle fatigue cracks were seen to be initiated from the precipitate‐free zone and oxidized‐surface carbides. It is corroborated that the higher GNDs were observed at carbide/matrix, eutectic/matrix, γ′/matrix interfaces, and in the interdendritic areas where voids and cracks formed. The higher GNDs at these sites facilitate crack initiation and propagation. Highlights: The fatigue life of alloy IN 713 C is highly sensitive to the microstructure.Higher tendency for carbide cracking was observed at high Δε/2.Cracks are seen to be initiated in PFZ and at oxidized MC carbides.Higher GND density was observed near carbides and eutectics. [ABSTRACT FROM AUTHOR]

The ability to economically offer distinct properties within a single component has gathered significant attention for bimetallic or cladded tubular components across various industries. A novel friction stir-based cladding method and its in-depth analyses to achieve internal cladding of Al inside the stainless steel (SS) tubes are presented. The process outcome with the variation in process parameters and its impact on heat generation and intermetallic compounds (IMCs) formation was analyzed. In this process, the joining between the base substrate and the cladded material is due to the heat generation that leads to interdiffusion and ultimately promotes the formation of IMCs. The mechanism of IMCs formation, its growth phenomenon, and its impact on joining efficacy were investigated. The cladded Al exhibited an approximately twofold increase in grain size compared to the base Al alloy, as revealed through electron back-scattered diffraction (EBSD) analysis. The coarser grains help to restrict the propagation of fracture during the flattening test. The cladded tube exhibits no sign of delamination after compression, which paves the way for the industrial adoption of the process. [Display omitted] • Friction stir backward extrusion based bimetallic tubular component fabrication. • Analysis of heat generation and its impact on the formation of IMCs. • Confirmation of Al-rich IMCs at the interface and its effects on bonding. • Uniform IMC layer thickness (3-4 µm) results in optimum bond strength at interface. • A twofold increase in the grain size of Al, resulting in resistance to delamination. [ABSTRACT FROM AUTHOR]

Copyright of Iron Steel Vanadium Titanium is the property of Iron Steel Vanadium Titanium Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)