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Abstract The PZT ceramics with different weight content from 78% to 89% were printed using the stereolithography method. The piezoelectric properties as well as the microstructure of the ceramics were investigated in detail. X-ray patterns and Raman spectra demonstrate that the steady PZT tetragonal phase has already formed in these sintered ceramics. Besides, the piezoelectric constant and dielectric constant were 212–345 pC/N and 760–1390, which were sligthly lower than that of the dry pressing disk. Furthermore, a two-dimensional ultrasound transducer array (8 × 8) was designed and developed to evaluate the properties of the 3D-printed PZT ceramics. [ABSTRACT FROM AUTHOR]

Plasma electrolytic oxidation (PEO) treatment has been performed on AZ91 Mg alloy in a silicate-containing alkaline electrolyte to disclose the relationship between second phase and resultant coating. The morphology and corrosion behavior were characterized for PEO coatings on three different AZ91 substrates with microstructures altered by heat treatment. In the presence of β phase, both the substrate and PEO coating exhibit enhanced corrosion resistance with finer and more evenly distributed β phase precipitates. In the as-cast AZ91, the anodized coating displays chemically and morphologically discontinuity on α and β phase with very coarse and defective regions on two-phase boundaries. In aged AZ91 with nano-sized β phase precipitates, the PEO coating shows no obvious difference on two-phase boundaries and is more homogenous with fewer pores and defects. The residual stress values given by X-ray diffraction (XRD) analysis indicate that PEO coating on aged AZ91 with finest β phase has the smallest stress which might be the reason for its improved corrosion resistance under synergetic effect of corrosive ions and residual stress. Conversely, in the absence of β phase, i.e. after solid solution treatment, the coating is characterized by the most inhomogeneous microstructure and the worst corrosion resistance, presumably owing to the absence of protective aluminum-containing oxides in the coating and more severe localized oxidation behavior adjacent to AlMn phase. Understanding the effect of second phase on PEO coating will enable us to optimize porous oxide structures for improved corrosion resistance by properly altering the substrate microstructure. [ABSTRACT FROM AUTHOR]

Laser powder bed fusion (LPBF)-fabricated Al matrix composites reinforced with SiC particles are strongly influenced by SiC particle features. In this study, the microstructural features, mechanical properties, and porosity of moderate volume fraction (10 vol%) microscale SiC-particle-reinforced AlSi10Mg composites fabricated by LPBF under different oxidation temperatures of SiC particles were investigated. The results demonstrate that LPBF-deposited SiC p /AlSi10Mg composites mainly exhibited laser track segments in macroscale and fine cellular-like dendrite grains and (Al + Si) eutectic phases within the melt pool on a microscale. The transition layer of MgAl 2 O 4 was present around the SiC particles in the oxidized-SiC p reinforced AlSi10Mg composites. In addition, the pore spatial distribution of the deposited composites using the microcomputed tomography test and the microstructural formation mechanism using Thermal Calc software were also studied. Using the finite element to model the deposited composites, it was found that the stress and strain distribution presented higher values than those without long-stripe precipitation phases in the deposited parts with long-stripe precipitation phases. The LPBF-fabricated oxidized-10 vol% SiC p /AlSi10Mg composite part with a relatively large ultimate tensile strength (∼405.3 MPa), relative density (∼98.89%), compressive strength (∼1046 MPa) and friction coefficient (0.32) were obtained. In particular, the ultimate tensile strength was larger than that of the other reported SiC p /AlSi10Mg composites with similar volume fractions and particle sizes. • The microstructures and mechanical properties of L-PBF 10 vol% oxidized-micro-scale SiC p /AlSi10Mg composites were studied. • Pores spatial distribution of deposited composites was studied by micro-CT. • Deformation behavior of composites under tensile conditions was performed by finite element modeling. • The reinforcement types and their formation process were discussed. [ABSTRACT FROM AUTHOR]

Ca/Mg/Al/Fe layered double hydroxides (LDHs) were synthesized through coprecipitation using steelmaking slag as raw material. The structural morphology of Ca/Mg/Al/Fe LDHs was characterized, and results revealed a well-defined shape with obvious intercalated structure under pH 12 at 150 °C. The presence of acetate groups in the LDHs interlayer was further confirmed. Ca/Mg/Al/Fe LDHs was used to absorb methyl orange from aqueous solution. The results demonstrate that the as-prepared Ca/Mg/Al/Fe LDHs exhibit excellent absorption capacity (58.18 mg/g) towards methyl orange in aqueous solutions when the initial methyl orange concentration was at 50 mg/L This result is practically significant for absorbent selection to control environmental pollution. [ABSTRACT FROM AUTHOR]

Cobalt–chromium–molybdenum (CoCrMo) alloys are widely applied as wear-resistant material. This article aims to illustrate the influence of phase constitution and precipitate morphology on the wear behavior of hot-pressed high carbon alloys. Wear behavior of two kinds of CoCrMo alloys, HP (hot-pressed) and HPA (hot-pressed+annealing) with various microstructure, hardness and surface topography were evaluated in detail. The ε phase dominant HP alloy with homogenous lamellar precipitates demonstrates higher hardness, consequently lower coefficient of friction and prominent wear resistance with mild sliding wear. In contrary, the γ phase dominant HPA alloy with carbide-free grains was characterized by abrasive wear of micro grooves. The matrix hardness strengthened by ε phase is more significant to affect wear behavior than precipitate hardening. Homogenous lamellar precipitates have a stand-out effect to block abrasion and accumulate tribochemical products. [ABSTRACT FROM AUTHOR]

Effect of dissolution and precipitation of Nb on the phase transformation during cooling was investigated. It is firstly recognized that either the formation of acicular ferrite or the separation of bainite ferrite could be adjusted by the preparation of the steel specimens with different amounts of solute Nb and Nb-precipitates in austenite (isothermally holding at 850°C for different durations). An increase in isothermal duration at 850°C would spawn more Nb(CN) precipitates, leading to a microstructural evolution from bainite ferrite to acicular ferrite/bainite ferrite dual phase, and eventually to acicular ferrite in the final microstructure. This could be explained by the solution of Nb in the austenite, due to the solute dragging effect of Nb, can decrease the Ar3 temperature and promote the formation of bainite ferrite, while the precipitation of NbC can increase the Ar3 temperature and promote the formation of acicular ferrite by increasing the nucleation sites of acicular ferrite. Thus, the properties of acicular ferrite/bainite ferrite dual phase steel can generally be improved by appropriately controlling the state of Nb (Nb(CN) as precipitates and Nb in solution) in the austenite before cooling, which provides a new approach to the modification of acicular ferrite/bainite ferrite ratio. [ABSTRACT FROM AUTHOR]

Abstract: The mechanical properties of anode materials play an important role in the reliability and durability of solid oxide fuel cells operating at high temperatures in a reducing environment. In this paper, we produced the results of the mechanical properties investigation of Ni/10mol% Sc2O3–1mol% CeO2–ZrO2 cermet anodes. Young''s modulus as well as strength and fracture toughness of non-reduced and reduced anodes has been measured, both at room and at high temperatures. High temperature experiments were performed in the reducing environment of forming gas. It is shown that while at 700°C and 800°C, the anode specimens exhibited purely elastic deformation and brittle fracture, a brittle-to-ductile transition occurred for heating above 800°C and the anode deformed plastically at 900°C. Fractography of the anode specimens were performed to identify the fracture modes of anodes tested at different temperatures. [Copyright &y& Elsevier]

Abstract: The microstructure and electric properties of the rhombohedral–tetragonal morphotropic phase boundary (MPB) composition 0.8Bi1/2Na1/2TiO3–0.2Bi1/2K1/2TiO3 have been investigated. X-ray and electron diffraction results substantiate the co-existence of tetragonal and rhombohedral phases. The ferroelectric domains were clearly observed by electron microscopy. The oxygen octahedron tilting of the samples was studied by SAED. Both saturated polarization–electric field and butterfly shaped strain–electric field hysteresis loops prove that the MPB composition shows typical ferroelectric nature. The detailed microstructure–property characterization may shed light on the physical property of further work on BNT–BKT around morphotropic phase boundary. [Copyright &y& Elsevier]

Abstract: Two series of raw materials were adopted to form TiAl/Ti2AlC composites: Ti/Al/TiC and Ti/Al/C. Differential thermal analysis (DTA) of starting powers and X-ray diffraction (XRD) of samples sintered at different temperatures from 600°C to 1300°C by hot pressing were utilized to analyze the phase transformation and the mechanism of synthesis. Scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) was utilized to investigate the morphology characteristics of the products. The experimental results showed that Ti reacted with Al to form TiAl intermetallics below 900°C; and above 900°C, TiAl reacted with TiC to produce dense TiAl/Ti2AlC composites. The products sintered at 1200°C had fine crystals and dense fibres, and the distribution of Ti2AlC particles in TiAl matrix was homogeneous. [Copyright &y& Elsevier]

A series of quasi-static and dynamic uniaxial compression experiments over a wide range of temperatures were conducted on polyurea elastomer. The stress-strain response of polyurea exhibits extreme nonlinearity, temperature and strain-rate sensitivity. How to comprehensively describe these complex behaviors regulated by the unique micro-structure of polyurea is still an open question. In this paper, a nonlinear viscoelastic constitutive model for polyurea is developed. The nonlinear viscoelasticity, entropic and energetic elasticity are taken into account, correlated with the interaction of chain segments, the stretch of molecular chains and covalent bonds from the perspective of molecular structure. The viscoelastic response is formulated by the hereditary integral of relaxation modulus and strain rate with time. The real time is accelerated by shift factor, which depends on the free volume. A new mechanism of shear-induced increase of free volume, which gives rise to the nonlinearity of viscoelasticity, is proposed, and the corresponding rate-dependent evolution equation of fractional free volume is developed. Parameters in the model are determined through the compression experiments and DMA test. Comparison with experimental data, as well as the data from references, verifies the ability of the model to predict the nonlinear stress-strain response of polyurea over a wide range of temperatures and strain rates. • Quasi-static and dynamic compression were conducted on polyurea over a wide range of temperatures. • A new mechanism of shear-induced increase of free volume is proposed. • A free volume based nonlinear viscoelastic constitutive model is established for polyurea. • The model predicts the response of polyurea over a wide range of temperatures and strain rates. [ABSTRACT FROM AUTHOR]

Quasicrystals have been used in various applications to improve wear resistance as well as friction. It is known that quasicrystal (i-phase) content and microstructure in alloys have a decisive effect on the mechanical properties and tribological performance. In this research, four (β + i)-dual-phased quasicrystal alloys with different i-phase content and grain size were developed to alleviate the brittleness of the i-phase with the help of the soft β-phase. The influences of the i-phase content and grain size were investigated through impact test, wear test, and analysis. Through the annealing process, the amount of the i-phase was increased by about 38% (59.24% → 81.75%), and, besides, the grain size of the i-phase was simultaneously increased from 3.47 μm up to 9.98 μm. As the amount of i-phase increased, it was possible to increase the hardness from 712 HV to 763 HV. Meanwhile, the increased grain size (i-phase) reduced the contact stress of the grain during wear testing; thus, the specific wear rate could be decreased from 2.21 × 10−4 mm3/Nm to 0.5 × 10−4 mm3/Nm. Not only that, but an experimental wear equation was obtained using empirical data to predict the wear behavior of the dual-phased alloys. Design of dual-phased quasicrystal alloys with different i-phase content; 59.24% (0 h), 68.85% (12h), 75.84% (24 h), and 81.75% (36 h) under a 600 °C annealing process. The higher content of i-phase in quasicrystal alloy shows a favorable tribological behavior because of the microstructure and mechanical properties of the dominant i-phase. Unlabelled Image • Dual-phased quasicrystal alloys were developed by a simple processing procedure. • The wear resistance is enhanced according to the increase of the i-phase. • The ductile beta-phase in dual-phase quasicrystal alloys reduces the cracking. • The optimal concentration of the two phases was found for the best tribological performance. [ABSTRACT FROM AUTHOR]

Highlights • 205A aluminum part fabricated using robotic CMT technology. • In-situ 3D tensile propertied characterization using X-ray microscopy. • Periodic refined α-Al grains with dispersed dot-like Al 2 Cu within AM part. • Homogenous spherical pores with a relatively high porosity within AM part. • Enhanced tensile strength, while a slightly deteriorated plasticity for AM part. Abstract 205A aluminum thin-wall part was additively manufactured using cold metal transfer (CMT) equipment. The influence of α-Al grains, Al 2 Cu phase, and pore characteristics on the in-situ tensile behavior was investigated. The experimental results show an enhancement in the ultimate tensile strength (UTS) in the as-deposited sample, as compared to its as-cast counterpart. This can be largely attributed to the presence of the refined α-Al grains more than dot-like Al 2 Cu phase. A slightly deteriorated plasticity was observed, which was mainly related to micro-scaled spherical pores with a relatively high porosity of 3.51%. [ABSTRACT FROM AUTHOR]

Wire arc additive manufacturing (WAAM) technology was adopted to deposite 2Cr13 thin-wall part using robotic cold metal transfer (CMT) equipment; the process stability, phase identification, microstructural evolution, and tensile properties in different layers were investigated. The results showed that a smooth surface was obtained for each layer due to the stable droplet transfer process, which ensured a stable deposition process. Positions in different layers had no significant influence on the structural aspects of the as-fabricated part according to XRD results. Elongated ferrite grains and fine-grained acicular martensite within the matrix in the top layer were recrystallized, instead of a spatial periodicity of martensite laths within equiaxed ferrite grains in the inner layers. Martensite content was increased gradually away from the base metal in the 05–25 th layers except nearly 100% martensite in the first layer. Long axis of martensite laths was randomly distributed in the X-Y plane in the both top and middle regions, while an epitaxial growth parallel to the building direction was found in the X-Z and Y-Z planes. Higher homogeneous ultimate tensile strength (UTS) and strong anisotropy in poorer ductility were obtained for the AM part when compared with the as-solutioned counterpart. Fracture behavior was transformed from ductile to mixed-mode, and finally to brittle from the 01 st layer to the 25 th layer. [ABSTRACT FROM AUTHOR]

Asymmetric-structured La 5.5 W 0.6 Mo 0.4 O 11.25-δ (LWM) ceramic membranes were fabricated by phase-inversion process followed by sintering. Finger-like pores with distributed small pores extend through most bulk of the membrane and reduce the thickness of the dense layer. The hydrogen permeation properties of the LWM asymmetric membranes were investigated as a function of temperature and H 2 partial pressures in feed gas at the temperature range from 800 °C to 1000 °C. The hydrogen permeation flux as a function of time at 900 °C under humid atmosphere was also investigated. Compared with the conventional symmetric dense LWM membrane, the hydrogen permeation flux through the asymmetric membrane is tripled. Furthermore, the chemical stability of LWM oxides after phase-inversion process and H 2 permeation were confirmed by XRD. [ABSTRACT FROM AUTHOR]

"Self-sharpening", a material maintaining its acute head shape during penetration, is highly desirable in a wide range of engineering applications. However, it remains a great challenge to make it occur in conventional single-principal-element alloys. Here, we develop a new chemical-disordered multi-phase tungsten high-entropy alloy that exhibits outstanding self-sharpening capability, in sharp contrast to conventional tungsten alloys only showing mushrooming. This alloy consists of a BCC dendrite phase and a rhombohedral μ phase embedded in the continuous FCC matrix, and such a unique microstructure leads to a 10–20% better penetration performance than conventional tungsten heavy alloys. We show that emergence of the self-sharpening is triggered by the ultrastrong μ phase stimulated dynamic recrystallization softening mediated shear banding. This study sheds light on the origin of self-sharpening and might open new opportunities for developing high-performance penetrator materials. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Abstract: 1–3 and 2–2 types Pb(Zr0.53Ti0.47)O3–CoFe2O4 (PZT–CFO) composite films with controllable microstructures, consisted by CFO nanopillar embedded in PZT matrix and PZT–CFO gratings respectively, have been fabricated on Pt/Ti/SiO2/Si substrates by combining lithography technology and pulsed laser deposition. X-ray diffraction confirms that the films are well crystallized under optimized postannealing conditions. Scanning electron microscope reveals that the periodic microstructures can be well controlled. Especially, intrinsic room temperature ferroelectric and ferrimagnetic behaviors are observed simultaneously. The structure–properties relationship is discussed. Our results may provide an alternative method to design and prepare multiferroic composite films with controllable microstructures. [ABSTRACT FROM AUTHOR]

CoCrFeMnNi high-entropy alloys (HEAs) are additively manufactured by laser directed energy deposition (L-DED) and laser powder bed fusion (L-PBF) processes. Comparative studies are conducted for the microstructures and deformation mechanisms of L -DED and L -PBF samples. In both types of samples, highly heterogeneous microstructures are formed, consisting of columnar grains, solidification cells, and dislocation networks. However, substantial differences are measured in the crystallographic texture, cell size, and elemental distribution. Deeper melt pools in the L -DED samples promote a mixed crystallographic texture of <101>/<111> as opposed to <001> along the build direction in the L -PBF samples. The <101>/<111> texture elevates the flow stresses and facilitates the activation of deformation twins in the L -DED samples. Moreover, their larger solidification cell sizes and associated chemical segregation across cell walls increase the dislocation storage capability and resistance to dislocation motion, leading to profuse planar slip bands and microbands during plastic deformation. The enhanced plastic deformation capabilities in the L -DED samples give rise to more sustained strain hardening and thus higher ductility compared to the L -PBF samples. Our work not only provides fundamental insights into the deformation mechanisms of additively manufactured HEAs, but also underscores the critical impact of processing conditions on the solidification microstructure and material design by additive manufacturing. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, a ceramic suspension with appropriate viscosity was prepared by optimizing the powder solid content and the dispersant content. An Al 2 O 3 -ZrO 2 ceramic green body was fabricated using the SLA technique, followed by the application of a liquid drying and two-step debinding process to prepare the defect-free Al 2 O 3 -ZrO 2 ceramic green body. The relative density, phase composition, microstructure, grain size, and mechanical properties of Al 2 O 3 -ZrO 2 samples sintered at different temperatures were compared. The main results indicated that the sample density increased with the sintering temperature until reaching a maximum density of 4.28 g/cm 3 at 1600 °C. When the temperature further increased to 1650 °C, the density dropped instead. With increasing sintering temperature, both the number of grain boundaries and the number of pores located at the grain boundaries reduced greatly. The Vickers hardness of the samples first increased and reached its maximum at 1550 °C with a value of 17.6 GPa, and then decreased with further increases in sintering temperature. The fracture toughness increased with the sintering temperature and reached a maximum value of 5.2 MPa·m 1/2  at 1650 °C. A sintering kinetics window which could offer the relationship between the sintering temperature and the relative density & grain size was set and also the microstructure evolution of the sintered body was conducted to get a deeper understanding of the 3D printing Al 2 O 3 -ZrO 2 composites. [ABSTRACT FROM AUTHOR]

Chromium nitride coatings are synthesized on the stainless steels by plasma immersion ion implantation and deposition. The microstructure and tribocorrosion behaviors of the as-deposited coatings are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, reciprocating-sliding tribometer and electrochemical testing. The results show that the CrN coatings have a typical columnar growth structure consisting of face-centered cubic crystals. The CrN coatings greatly enhance the corrosion resistance and wear resistance of the stainless steel. However, frictional forces induce numerous micro-cracks which act as the diffusion channels for NaCl solution. Multi-scale Cl ion corrosion occurs simultaneously during the tribocorrosion and a force-corrosion synergy interaction induces the multi-degradation (e.g., intersecting cracks and layer delamination) of the CrN coating. The synergistic damage mechanisms of wear and corrosion are systematically discussed. [ABSTRACT FROM AUTHOR]

The study of ZrTe 5 is revived because theory predicts the quantum spin Hall effect in monolayer ZrTe 5 and topological phase in bulk ZrTe 5 . To study the topological property of ZrTe 5 , the growth of large size and high-quality single crystals is the first and crucial step. Here, by mean of iodine (I 2 ) transport agent, centimeter-sized ZrTe 5 single crystals were successfully grown by the chemical vapor transport technique. The microstructure characterization reveals that grown ZrTe 5 crystal has “stacking stripes of wood” morphology, and growth mechanism is proposed accordingly. The size of grown ZrTe 5 crystals can be reached as large as 35×2×0.5 mm 3 , which enable us to measure the a -, b - and c - axis anisotropic resistance. Large and single crystalline ZrTe 5 crystals provide a solid basis for exploring its topological phase. [ABSTRACT FROM AUTHOR]

Nano/micro-carrier systems have shown promising application in the biomedical field as various delivery carriers. The composite material and fabrication method determine their microstructures, properties and thus their potential applications. Since approved as tablet coating material by the U.S. Food and Drug Administration (US-FDA), zein has been widely investigated as one of protein-based materials in the past few decades. Zein is renewable, biodegradable and relatively inexpensive in comparison with animal proteins ( e.g ., gelatin and albumin). This paper reviews the current landscape of zein-based nano/micro-carrier systems, with particular emphasis on nano/microparticles, nano/microcapsules and their design, fabrication, assembly mechanisms and biomedical applications especially for controlled drug delivery. The benefits, challenges and related solutions of zein-based colloidal carrier systems are also discussed. In addition, investigations on the molecular structure, biocompatibility and immunogenicity of zein are summarized and discussed. [ABSTRACT FROM AUTHOR]

In this work, the morphology, crystallization process and crystal structure of the phase-change material TiSbTe (TST) alloy have been successfully established, which is essential for applying this alloy in phase-change memory. Specifically, atomic force microscopy (AFM) was employed to characterize the as-deposited and post-annealed thin films, and transmission electron microscopy (TEM) analyses of the films annealed in situ were used in combination with selected-area electron diffraction (SAED) and radial distribution function (RDF) analyses to investigate the structural evolution from the amorphous phase to the polycrystalline phase. Moreover, the presence of structures with medium-range order in amorphous TST, which is beneficial for high-speed crystallization, was indicated by the structure factors S(Q)s . The crystallization temperature was determined to be approximately 170 °C, and the grain size varied from several to dozens of nanometers. As the temperature increased, particularly above 200 °C, the first single peak of the rG(r) curves transformed into double shoulder peaks due to the increasing impact of the Ti Te bonds. In general, the majority of Ti atoms were doped into the SbTe lattice and tended to form structural defects, whereas the remainder of the Ti atoms aggregated, leading to the appearance of TiTe 2 phase separation, as confirmed by the SAED patterns, high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) images and corresponding energy-dispersive X-ray (EDX) mappings. [ABSTRACT FROM AUTHOR]

Abstract: Chromium carbide (Cr3C2) nanopowders can be synthesized by carbon thermal reduction of nanometer chromic oxide (Cr2O3) and with nanometer carbon black. Effect of reaction time on phase composition and microstructure of chromium carbide nanopowders was researched under the conditions of 28wt.% C and 1100°C. The products were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric and differential scanning calorimetry (TG–DSC) and X-ray photoelectron spectroscopy (XPS) techniques. The results show that the product is mainly composed of Cr2O3 when the reaction time is 0.5h, and the diffraction peaks of carbon are not observable. Some powders show a spherical morphology, others appear as fused mass. The powders with the single phase of Cr3C2 can be synthesized at 1h, and an average crystallite size of 26nm. The powders show good dispersion and are mainly composed of spherical or nearly spherical particles with a mean diameter of about 30nm. Compared with those of 1h, the diffraction lines of Cr3C2 synthesized at 1.5h and 2h shift toward smaller angles, and the powders exhibit a lot of agglomerated particles. [Copyright &y& Elsevier]

Highlights: [•] Systematically and comparative microstructure analysis for the SrIrO3 thin films. [•] Meta-stable orthorhombic SrIrO3 phase was obtained under normal conditions. [•] The stabilization of meta-stable orthorhombic SrIrO3 was quantitatively understood by lattice mismatch strain. [ABSTRACT FROM AUTHOR]

Abstract: Double perovskite Sr2Fe10/9Mo8/9O6 films with different thicknesses have been prepared on (111)-SrTiO3 substrates by pulsed laser deposition in flowing N2 atmosphere. The X-ray diffraction indicates the films have no impurity phases and are (111) oriented. The epitaxy and local Fe/Mo ordering are confirmed by high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED). Mixed valence states of interior Fe and Mo cations are observed by the x-ray photoelectron spectroscopy. Interestingly, the films show significantly thickness-dependent magnetization properties: at 10K, the films show the saturated magnetization of 2.30μB/f.u. (formula unit), 1.12μB/f.u., and 0.50μB/f.u., respectively. On the other hand, the thickest film shows a magnetoresistance of −13% at 120K whereas other two samples show considerably higher resistivity and neglectable MR. The thickness effects on microstructure and properties have been discussed in detail. [Copyright &y& Elsevier]

Abstract: We present a structural and kinematic study of an Early Paleozoic subduction mélange and a magmatic arc that form the main elements of the Southern Orogen Belt of Inner Mongolia, which lies in the eastearn part of the Altaids or Central Asia Orogenic Belt. The structural analysis of the mélange conducted in the Hongqi and Ondor Sum areas (western Inner Mongolia) shows two phrases of ductile deformation. The D 1 event is responsible for the pervasive S 1 foliation, NW–SE striking L 1 stretching lineation and F 1 intrafolial folds. These microstructures are coeval with a greenschist facies metamorphism. During D 2, NW-verging F 2 folds associated with a S 2 axial planar cleavage deformed S 1 and L 1. The D 1 kinematic criteria indicate a top-to-the-NW sense of shear. D 1 and D 2 developed before the unconformable deposition of the Early Devonian shallow water sandstone. A lithosphere scale geodynamic model involving an Early Paleozoic southeast-directed subduction beneath the North China Craton and late Silurian collision of the North China Craton with an hypothetical microcontinent is proposed to account for the microstructural evolution. [Copyright &y& Elsevier]

Abstract: Cu/Mo duplex coating was introduced as interfacial modification layer to investigate its effect on the interfacial microstructure and the mechanical properties of SiCf/Ti6Al4V composite. The results show that the copper coating has completely diffused into the matrix and made the matrix form brittle substances like Widmanstaten structure which contains Ti2Cu and α-Ti. The Mo coating has become Mo–Ti mixed coating. However, the longitudinally tensile strength of the composite is excellent as the Cu/Mo duplex coating can hinder the fiber/matrix interfacial reaction. [Copyright &y& Elsevier]

Abstract: The solution-derived precursor method was used to synthesize chromium carbide (Cr3C2) nanopowders, ammonium dichromate ((NH4)2Cr2O7) and nanometer carbon black were used as raw materials. The products were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The results show that the single phase Cr3C2 can be synthesized under the conditions of 21wt.%C, 1100°C and 30min, and the average crystallite size is 27.2nm. The powders show good dispersion and are mainly composed of spherical or near- spherical particles with a mean diameter of ~30nm. The surface of the specimen mainly consists of Cr, C and O three species elements. The XPS spectrum of Cr2p consists of two peaks with the binding energies of 577.5eV and 575.3eV, which are assigned to the Cr2p3/2 species of Cr2O3 and Cr3C2− x (0≤ x ≤0.5), respectively. The XPS spectrum of O1s energy region for chromium carbide contains three peaks (Oa, Oh and Od), which are considered to be due to O−, OH− and Cr2O3, respectively. [Copyright &y& Elsevier]

Abstract: The creep-rupture lives of Sn3.8Ag0.7Cu and Sn3.8Ag0.7Cu0.03Ce lead-free solder joints for electronic packaging were investigated, respectively. And the relationship between creep behavior and intermetallic compound (IMC: Ag3Sn, Cu6Sn5, CeSn3) particles in SnAgCu/SnAgCuCe solder joints has been obtained. Meanwhile, rare earth Ce concentration gradient and retardation effect of Ce on the IMC layer have been observed at the solder/Cu interface. Moreover, aging reaction of Sn and Cu, and the effect mechanism of rare earth Ce on two IMCs (Cu6Sn5 and Cu3Sn) are reported. [Copyright &y& Elsevier]

Abstract: A series of lead-free piezoceramics of (1− x)K0.5Na0.5NbO3–xBi0.8La0.2FeO3 [(1− x)KNN–xBLF, 0.005≤ x ≤0.04] were synthesized by conventional solid-state sintering. Crystal structures and microstructures of the ceramics were characterized by X-ray diffraction and transmission electron microscopy. X-ray diffraction substantiates the existence of an orthorhombic-tetragonal morphotropic phase boundary (MPB) near x =0.01. Highest electrical performances were observed near the MPB. The maximum remnant polarization, piezoelectric coefficient, and coupling factor were measured as 22.5μC/cm2, 144pC/N, and 0.34, respectively. The effects of BLF on structures and electrical properties were discussed. Our results might be helpful for developing KNN-based piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

Abstract: In order to improve the properties of Sn–3.8Ag–0.7Cu and Sn–0.5Cu–0.05Ni solders, 0–0.1wt.% of rare earth Ce was added to the base alloys, and the microstructures were studied. Meanwhile, the solderability of solders on Cu substrate was determined by the wetting balance method, the mechanical properties of soldered joints were investigated by the pull-force test and the fracture morphologies were analyzed. It is found that the new solder alloys possess better solderability than the base solder alloys, and the greatest improvement to the solderability of Sn–3.8Ag–0.7Cu–xCe is obtained with around 0.03–0.05wt.% Ce, while the optimal Ce content is in the range of 0.05–0.07wt.% for Sn–0.5Cu–0.05Ni–xCe solders. The results also indicate that the mechanical properties of soldered joints are improved with increasing Ce addition, with peak mechanical properties at Sn–3.8Ag–0.7Cu–0.03Ce and Sn–0.5Cu–0.05Ni–0.05Ce. The grain sizes of solder alloys are refined due to the addition of Ce, thus the mechanical properties of soldered joints are improved simultaneously. [Copyright &y& Elsevier]

Abstract: La-substituted BiFeO3, Bi0.8La0.2FeO3, thin films were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. X-ray diffraction and high-resolution transmission electron microscope were used to analyze the structures of the films. The results show the films fabricated under optimized growth condition are (012) textured. X-ray photoemission spectroscopy results indicate that the oxidation state of Fe ion is Fe3+ in the films without detectable Fe2+. The films show low leakage current and excellent dielectric characters. Multiferroic properties with a remnant ferroelectric polarization of 5.2μC/cm2 and a remanent magnetization of 0.02μB/Fe were established. These results have some implications for further research. [Copyright &y& Elsevier]

CrWN glass molding coatings with different W contents were synthesized by plasma enhanced magnetron sputtering (PEMS). The microstructure, mechanical, wear resistance, and anti-oxidation properties of as-deposited coatings were investigated using various techniques and tests. The results showed that the as-deposited coatings exhibited typical columnar growth structure, consisting of layered CrN and W 2 N, and showed increased lattice expansion and hardness enhancement with increasing W content. Whereas the coating with high H/E value showed better toughness to resist fatigue deformation and fracture, which eventually resulted in excellent wear performance and low wear rate of 0.89 × 10−6 mm3/Nm. Annealing revealed that the as-deposited coating with low W content showed a slight increase in thickness and Ra value because of high volume fraction of Cr 2 O 3 phase, which effectively delayed the oxidation reaction and suppressed the expansion of WO 3 phases. With the increase in W content, the rising volume fraction of WO 3 phases weakened the stabilized effects of Cr 2 O 3 phases and eventually led to a constant increase in thickness and Ra value of the annealed coating. The mold tests confirmed that the CrWN coating showed a stable structure and excellent chemical inertness and anti-sticking performance, making it a potential coating for glass molding processes. • Microstructure, wear and oxidation resistance of CrWN coatings are investigated. • The coating shows a multilayer columnar structure of CrN and W 2 N phases. • The coating with high H/E value shows better toughness and anti-wear performance. • The coating undergoes aggravated oxidation damage with the increase of W content. • The oxidation damage induces severe volume expansion and surface coarsening. [ABSTRACT FROM AUTHOR]

The CrWN glass molding coating was synthesized by plasma enhanced magnetron sputtering (PEMS). The effect of annealing environment (e.g., vacuum, N 2 and Air) on the microstructure and mechanical property of as-deposited coating was investigated by the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscope (AFM) and nanoindentation tests. Results showed that the as-deposited coating exhibited dense columnar structure consisting of multilayer CrN and W 2 N phases. The vacuum annealed coating showed similar thickness to that of as-deposited coating, but underwent visible surface coarsening because of slight oxygen erosion. The N 2 and air annealed coatings suffered from varying degree of oxidation damage accompanied by the formation of mixed WO 3 -CrWO 4 phases, which consequently resulted in severe thickness expansion and surface coarsening. The vacuum annealing induced a spinodal decomposition of supersaturated solid solution to form nm-sized CrN and W 2 N domains. Strain fields originating from the lattice mismatch eventually caused a pronounced age-hardening in the vacuum annealed coating. Whereas the N 2 and air annealed coatings showed significant mechanical degradation because these loose WO 3 -CrWO 4 oxides degraded the stable matrix structure. Our results clearly demonstrated that vacuum environment effectively suppressed the oxidation damage and mechanical degradation of glass molding coating. • The microstructure and mechanical property of the annealed coating are studied. • The vacuum annealing induces spinodal decomposition and light oxidation damage. • The N 2 and air annealing induce serious volume expansion and surface coarsening. • The vacuum annealed coating shows a pronounced age-hardening effect. • The N 2 and air annealed coatings suffer from remarkable mechanical degradation. [ABSTRACT FROM AUTHOR]

Controlled cold rolling impacts on microstructure and mechanical properties of the rare earth Ce-modified SAF 2507 super duplex stainless steel (SDSS) are investigated towards a better application and development prospective over the pristine SDSS. Rolling was performed at room temperature with the deformation level in a range of 30%–90%. A large amount of dislocations into the ferrite phase turned out, and their density increased with the deformation. While, emergence of dislocation plugs group, ferrite grains get refined to nanometer scale during the deformation process. In addition to deformed bands within austenite, formation of α′-martensitic phases and significant increment in their volume fraction are detected and attributed to deformation-induced martensitic transformation. Elongation of the ferrite and austenite microstructures along the deformation direction under the action of high strain also resulted in fibers formation gradually. Correspondingly, significant increase in the strength index while decrement in the plasticity index are observed. Moreover, cold rolling deformation not only affects the tensile fracture morphology but also switches it from a typical ductile to a ductile and quasi-cleavage mixed fracture. [ABSTRACT FROM AUTHOR]