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Heterostructure or doping engineering on Mo2C by coupling with transition metal nanoparticles/atoms can optimize catalytic activities for oxygen evolution reaction (OER). However, the intrinsic catalytic activity of Mo2C is not fully stimulated at the atomic level, which is challenging. Herein, an adjacent‐confined pyrolysis strategy to manipulate the intrinsic electronic structure of Mo2C directly is reported. During the nucleation and growth of Mo2C, the replacement of Mo atoms by adjacent Ni atoms induces the generation of high‐density phase boundaries (PBs) with alternating face‐centered cubic (fcc) and hexagonal close‐packed (hcp) hetero‐phase. The lattice deformity in PBs affords an ultrahigh density of active sites, endowing Mo2C nanosheets with excellent OER activity and superior stability. Theoretical calculations reveal that introduced Ni atoms activate the adjacent Mo sites and optimize the thermodynamic reaction energetics for enhanced OER activity. The work offers a general adjacent‐confined pyrolysis strategy to achieve PBs‐controlling in Mo2C nanosheets for catalytic application and beyond. [ABSTRACT FROM AUTHOR]

Lead zirconia titanate (PZT) is the most often used piezoelectric material in various electronic applications like energy harvesters, ultrasonic capacitors and motors. It is true that PZT has a lot of significant drawbacks due to its 60% lead content, despite its outstanding ferroelectric, dielectric and piezoelectric properties which influenced by PZT's morphotropic phase boundary. The recently found potassium sodium niobate (KNN) is one of the most promising candidates for a new lead-free piezoelectric material. For the purpose of providing a resource and shedding light on the future, this paper provides a summary of the historical development of different phase boundaries in KNN materials and provides some guidance on how to achieve piezoelectric activity on par with PZT through a thorough examination and critical analysis of relevant articles by providing insight and perspective of KNN, which consists of detailed evaluation of the design, construction of phase boundaries and engineering for applications.

Lead zirconia titanate (PZT) is the most often used piezoelectric material in various electronic applications like energy harvesters, ultrasonic capacitors and motors. It is true that PZT has a lot of significant drawbacks due to its 60% lead content, despite its outstanding ferroelectric, dielectric and piezoelectric properties which influenced by PZT's morphotropic phase boundary. The recently found potassium sodium niobate (KNN) is one of the most promising candidates for a new lead-free piezoelectric material. For the purpose of providing a resource and shedding light on the future, this paper provides a summary of the historical development of different phase boundaries in KNN materials and provides some guidance on how to achieve piezoelectric activity on par with PZT through a thorough examination and critical analysis of relevant articles by providing insight and perspective of KNN, which consists of detailed evaluation of the design, construction of phase boundaries and engineering for applications. [ABSTRACT FROM AUTHOR]

The electrocatalytic CO2 reduction reaction (CO2RR) to fuels driven by electrocatalysts is a viable strategy for efficient utilization of emitted CO2. CO2RR involves multiple‐steps, including adsorption, activation, hydrogenation, etc. At present, copper‐tin alloy catalysts have shown the capability to reduce CO2 to formic acid or formate. However, their poor adsorption and activation capacities for CO2 molecules, as well as the sluggish kinetics in *H supply restrict the proton‐coupled electron transfer processes in the electrocatalytic CO2RR to produce formic acid. In order to solve the above problems, the ultra‐small SnO2/Cu6Sn5/CuO nanocatalysts with superscalar phase boundaries are fabricated by laser sputtering. The introduction of SnO2 enhances the adsorption and activation of CO2, while CuO promotes H2O decomposition and provides abundant *H intermediates, resulting in tandem catalytic sites on the SnO2/Cu6Sn5/CuO composite catalysts and thus leading to excellent CO2RR activity and high selectivity to formic acid. The Faradic efficiency of formic acid (FEHCOOH) at the SnO2/Cu6Sn5/CuO electrode reaches 90.13% along with a high current density of 25.2 mA cm−2 at −0.95 V versus reversible hydrogen electrode. The role of the multiphase boundaries constructed by introduction of oxides is confirmed by in situ infrared spectroscopy and kinetic isotope effects experiments, which is consistent with the design concept. [ABSTRACT FROM AUTHOR]

[Display omitted] • Variations of cutting forces occur at phase boudaries in machining Ti-6Al-4 V. • Force variations are related to the crystallographic orientation of workpiece. • The orientation, phase composition and slip systems on shear bands are varified. • Combining a constitutive model and geometric interplay between tool and workpiece. • Mechanism of boundaries effect on the cutting force variation is discussed. In micro-cutting, microstructure induced anisotropic properties highly affect the machinability of materials because the removal amount is almost on same level as the size of microstructures such as grains and phases. In this paper, cutting force fluctuation induced by different phases is theoretically and experimentally investigated in the micro-cutting of dual-phase Ti6Al4V alloy. Particularly, a significant change of cutting force was observed as the tool traverses phase boundaries. Furthermore, the mechanism of the variation of cutting forces is discussed from perspectives of crystallographic orientation, critical resolved shear stresses and slip systems. Constitutive model and geometrical relationship between the tool and workpiece are also proposed to analyzed the resolved shear stresses of phases with different crystallographic orientations. The results agree well with experimental data, indicating that activation of various slip systems is directly determined by the values of corresponding resolved shear stresses. Additionally, cutting force fluctuation is primarily attributed to the change of slip systems at phase boundaries in the micro-cutting. The main findings of this study present the significant role of crystallographic orientations and slip systems in governing cutting force fluctuations at phases and phase boundaries, which provide valuable insights for optimization of cutting parameters in machining of titanium alloys. [ABSTRACT FROM AUTHOR]

Dielectric polarization and magnetic resonance associated with intrinsic constituent and extrinsic structure are two kinds of fundamental attenuation mechanisms for microwave absorbers, but remain extremely challenging in revealing the composition‐morphology‐performance correlation. Herein, hierarchical MXene/metal‐organic framework derivatives with coherent boundaries and magnetic units below critical grain size are constructed to realize synergistic dielectric–magnetic enhancement by phase‐evolution engineering and dynamic magnetic resonance. Specifically, phase‐evolution induced inseparable interfaces, diverse incompatible phases, and defects/vacancies contribute to dielectric polarization, while closely distributed magnetic units simultaneously realize nanoscale multi‐domain coupling and long‐range magnetic interaction. As results, the hierarchical derivatives promise an exceptional reflection loss of −59.5 dB and an effective absorption bandwidth of 6.1 GHz. Both experimental results and theoretical calculations indicate that phase‐evolution engineering and dynamic magnetic resonance maximize the absorption capability and demonstrate a versatile methodology for manipulating microwave attenuation. More importantly, the proposed multi‐domain coupling and long‐range magnetic interaction theories innovatively offer dynamic magnetic resonance mechanism for magnetic loss within critical grain size. [ABSTRACT FROM AUTHOR]

The effect of the density of grain boundaries (austenite/austenite) and phase boundaries (austenite/particle) on hydrogen embrittlement was studied in high nitrogen austenitic steel Fe-19Cr-21Mn-1.3V-0.2С-0.8N (mass %). Experiments revealed that the microscopic structural parameters such as lattice distortions, phase and grain boundaries affect the macromechanical behavior of the hydrogen-charged steel. With increasing density of grain and phase boundaries and decreasing lattice distortion of the austenitic phase, hydrogen atoms absorbed during electrolytic hydrogen charging are redistributed from interstitial positions in austenitic grains to the boundaries. This leads to a decrease in hydrogen-assisted solid solution strengthening of austenite, reduces the hydrogen-induced increase in the steel yield stress, and suppresses transgranular but promotes intergranular fracture of the hydrogen-affected layer in the tensile specimens. It was experimentally shown that an increase in the grain boundary density only, with other structural parameters unchanged, slightly improves the resistance of steel to the negative effects of hydrogen, while an increase in the total density of grain and phase boundaries has the opposite effect. [ABSTRACT FROM AUTHOR]

One big risk for commercial solid oxide fuel cells (SOFCs) is the potential delamination between cathode and electrolyte layers. It can be effectively alleviated by the thermal expansion offset strategy proposed in 2021, i.e., conventional cathode composited with the negative thermal expansion oxides. Here novel composite cathodes designated as La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF)-xSm 0.85 Zn 0.15 MnO 3 (SZM) (x = 0, 5, 10, 15, and 20 wt.%) are developed. Random phase boundaries with apparent lattice distortion are formed between LSCF and SZM phases. The best electrochemical performance is obtained for x = 10%. The corresponding peak power density at 923–723 K is 1.151–0.147 W·cm−2, which is 57–69% higher than that (0.731–0.087 W·cm−2) for x = 0. More importantly, markedly enhanced long-term and thermal cycling stability is also obtained. Results of electrical conductivity, electrochemical impedance spectroscopy (EIS) and distribution of relaxation time (DRT) results further confirm that improved thermal match between cathode and electrolyte layers should be responsible for the high performance of intermediate temperature SOFCs (IT-SOFCs). • Thermal expansion offset composite cathodes LSCF-xSZM (x = 0–20 wt.%) are developed. • Random phase boundaries with lattice distortion are formed between LSCF and SZM. • The PPD of single cells with LSCF-10SZM cathode is 1.151 W⋅cm−2 at 923 K. • Thermal stability can be markedly improved with the novel cathode. [ABSTRACT FROM AUTHOR]

The paper presents and discusses questions on structure formation during the sintering process of Cr2O3-based composites using the hot pressing method, when a chemical reaction between the components takes place. The task was difficult because Cr2O3 decomposes when sintered at temperatures above 1300 °C. The proposed novel method allowed for interaction between aluminum and chromia, thus avoiding the decomposition of the latter. Here, ultrafine aluminum powder played the role of the active agent forming a liquid phase and reacting with Cr2O3. The appearance of the solid solutions of (Cr,Al)2O3 with different stoichiometry of Cr and Al depended on the aluminum content in the initial mixture. The solid solution significantly strengthened boundaries between composite phases, resulting in the composite material of high fracture toughness between 5 and 7 MPa m½ and bending strength of ca. 500 MPa. The best mechanical properties exhibited the cermet with 22 wt.% of the restored chromium. [ABSTRACT FROM AUTHOR]

A phase diagram, which is understood as a graphical representation of the physical states of materials under varied temperature and pressure conditions, is one of the basic concepts employed in high-pressure research. Its general definition refers to the equilibrium state and stability limits of particular phases, which set the stage for its terms of use. In the literature, however, a phase diagram often appears as an umbrella category for any pressure–temperature chart that presents not only equilibrium phases, but also metastable states. The current situation is confusing and may lead to severe misunderstandings. This opinion paper reviews the use of the "phase diagram" term in many aspects of scientific research and suggests some further clarifications. Moreover, this article can serve as a starting point for a discussion on the refined definition of the phase diagram, which is required in view of the paradigm shift driven by recent results obtained using emerging experimental techniques. [ABSTRACT FROM AUTHOR]

Developing high-performance lead-free piezoceramics, such as (K,Na)NbO 3 (KNN) material, is critical to achieving environmental sustainability in next-generation electromechanical devices. Although substantial advancements have been made in KNN-based ceramics, a general coherent framework is lacking that links microscopic structure to the enhancement of macroscopic properties. Our findings indicate that the enhanced performance of KNN-based ceramics in multiphase coexistence boundaries can be attributed to the formation of self-adjusting nanodomains in response to strong local structural heterogeneity. The self-adjusting behavior of domain structure is an outcome of minimizing the local stress generated by the lattice mismatch within KNN-based ceramics, which conforms to the thermodynamic principles that favor minimizing total free energy. Guided by this strategy, the present work achieves a significant improvement of electromechanical properties, including a piezoelectric coefficient (d 33) of ∼585 pC N−1, an electromechanical coupling factor (k p) of ∼62 %, and a figure of merit (d 33 × g 33) of ∼12.78 ×10−12 m2 N−1. This study offers a new strategy for developing lead-free piezoceramics through dedicated design of novel phase boundaries. [Display omitted] • The framework links microstructure to performance in lead-free piezoelectric ceramics. • Enhanced KNN-based ceramics' performance at phase boundaries is due to self-adjusting nanodomains. • Improved electromechanical properties of KNN-based ceramics: d 33 of 585 pC N-1 and k p of 62%. [ABSTRACT FROM AUTHOR]

We consider two related models for the propagation of a curvature sensitive interface in a time independent random medium. In both cases we suppose that the medium contains obstacles that act on the propagation of the interface with an inhibitory or an acceleratory force. We show that the interface remains bounded for all times even when a small constant external driving force is applied. This phenomenon has already been known when only inhibitory obstacles are present. In this work we extend this result to the case of - for example - a random medium of random zero mean forcing. The first model we study is discrete with a random forcing on each lattice site. In this case we construct a supersolution employing a local path optimization procedure. In the second, continuous, model we consider a random heterogenous medium consisting of localized small obstacles of random sign. To construct a stationary supersolution here, we need to pass through sufficiently many blocking obstacles while avoiding any obstacles of the other sign. This is done by employing a custom percolation argument. [ABSTRACT FROM AUTHOR]

A phase diagram, which is understood as a graphical representation of the physical states of materials under varied temperature and pressure conditions, is one of the basic concepts employed in high-pressure research. Its general definition refers to the equilibrium state and stability limits of particular phases, which set the stage for its terms of use. In the literature, however, a phase diagram often appears as an umbrella category for any pressure–temperature chart that presents not only equilibrium phases, but also metastable states. The current situation is confusing and may lead to severe misunderstandings. This opinion paper reviews the use of the “phase diagram” term in many aspects of scientific research and suggests some further clarifications. Moreover, this article can serve as a starting point for a discussion on the refined definition of the phase diagram, which is required in view of the paradigm shift driven by recent results obtained using emerging experimental techniques.

Zirconium is used as an alloying element owing to its ability to form carbides, nitrides, oxides, and other intermetallic compounds. Zirconium alloying has the high efficacy in increasing the oxidation and irradiation resistance of steel via the formation of Zr-containing complex oxides. Furthermore, the formation of oxides and intermetallic compounds was shown to inhibit corrosion. The use of Zr as an alloying element facilitated stabilization of the microstructure at elevated temperatures and under high-heat-input welding conditions. The present review summarizes studies examining the influence of Zr on the formation of Zr-containing phases, microstructure stabilization, and various properties, such as mechanical properties, high-temperature oxidation resistance, irradiation resistance, and corrosion resistance. Furthermore, the applications of Zr to four types of steels, i.e. Zr-containing oxide-dispersion strengthened (ODS) steels, Zr-containing stainless steels, Zr-containing heat-resistant steels, and high-heat-input welding steels, under different conditions were summarized and analyzed. [ABSTRACT FROM AUTHOR]

As an empirical tool in materials science and engineering, the iconic phase diagram owes its robustness and practicality to the topological characteristics rooted in the celebrated Gibbs phase law free variables (F) = components (C) - phases (P) + 2. When crossing the phase diagram boundary, the structure transition occurs abruptly, bringing about an instantaneous change in physical properties and limited controllability on the boundaries (F = 1). Here, the sharp phase boundary is expanded to an amorphous transition region (F = 2) by partially disrupting the long-range translational symmetry, leading to a sequential crystalline-amorphous-crystalline (CAC) transition in a pressurized In 2 Te 5 single crystal. Through detailed in situ synchrotron diffraction, it is elucidated that the phase transition stems from the rotation of immobile blocks [In 2 Te 2 ] 2+ , linked by hinge-like [Te 3 ] 2- trimers. Remarkably, within the amorphous region, the amorphous phase demonstrates a notable 25% increase of the superconducting transition temperature (T c ), while the carrier concentration remains relatively constant. Furthermore, a theoretical framework is proposed revealing that the unconventional boost in amorphous superconductivity might be attributed to an intensified electron correlation, triggered by a disorder-augmented multifractal behavior. These findings underscore the potential of disorder and prompt further exploration of unforeseen phenomena on the phase boundaries., (© 2024 Wiley‐VCH GmbH.)

Temperature- and irradiation-assisted failure mechanisms in miscible phase boundaries are clarified via atomistic calculations. We first establish the temperature-dependent brittle-to-ductile transition in U–Zr miscible phase boundaries. Our results confirm that these boundaries are mostly brittle at low temperatures and ductile at elevated temperatures. We then investigate the changes induced by irradiation on the fracture mechanisms in such phase boundaries. The irradiation-induced defect accumulation follows a multi-stage process that starts with the accumulation of isolated small dislocation loops before transitioning to the saturation and growth of larger dislocation loops and end up with a reorganization into forest dislocations. The accumulation of loops is the primary feature to participate in the delineation between brittle and ductile interfacial fracture in irradiated phase boundaries. At low damage levels, radiation defect interactions with the crack tip are limited and U–Zr miscible boundaries fail through the emission of dislocations ahead of the crack tip followed by brittle cleavage in agreement with the classical Griffith's criterion for crack stability. At higher damage levels, the failure mode transitions from brittle crack growth to ductile void growth. In this case, the microcrack tip is blunted by the high density of pre-existing, radiation-induced defects in the vicinity of the crack. This interaction leads to the development and growth of a cavity at the interface as opposed to interfacial cleavage. [ABSTRACT FROM AUTHOR]

Interface engineering has proven an effective strategy for designing high‐performance water‐oxidation catalysts. Interface construction combining the respective advantages of amorphous and crystalline phases, especially embedding amorphous phases in crystalline lattices, has been the focus of intensive research. This study concerns the construction of an amorphous−crystalline FeOOH phase boundary (a−c‐FeOOH) by structural evolution of iron oxyhydroxide‐isolated Fe(OH)3 precursors from one‐step hydrothermal synthesis. a−c‐FeOOH demonstrates superb electrocatalytic activity for the oxygen evolution reaction (OER) with overpotential of 330 mV to drive a current density of 300 mA cm−2 in 1.0 m KOH, which is among the best OER catalysts and much better than the pristine amorphous or crystalline FeOOH alone. Density functional theory calculations reveal that the high‐density a−c phase boundaries play a critical role in determining high OER activity. [ABSTRACT FROM AUTHOR]

Partial and integral thermodynamic functions of the mixing and evaporation of nickel–calcium melts are calculated from the values of calcium vapor pressure at 900–1300°C (1173–1573 K), determined using the boiling points approach (isothermal version), and those of nickel, found via numerical integration of the Gibbs–Duhem equation. It is established that the formation of alloys containing up to 65.5 mol % calcium (the rest is nickel) is exothermic, while at higher Ca content the process is endothermic. The excess entropy of mixing is negative up to a Ca content of ∼64 mol %, testifying to a certain ordering in the melts due to the existence of associates. Using data on the pressure of a saturated vapor of calcium and nickel, the state diagram is supplemented by the fields of the coexistence of melts and vapor at atmospheric pressure and in vacuums of 1.33 and 0.7 kPa. The location of the boundaries of the fields of vapor–liquid equilibrium confirms the possibility of separation of the Ni–Ca melts by distillation in a vacuum. [ABSTRACT FROM AUTHOR]

The present contribution examines the accessibility of diffusivities across the two-phase region of an equimolar methane–propane mixture for dynamic light scattering (DLS) experiments. Heterodyne DLS experiments and theoretical calculations of the Rayleigh ratio were performed at 125 different thermodynamic states including the gas, liquid, supercritical, and the two-phase region. The present measurements document that two diffusivities can be determined simultaneously in the liquid state and saturated liquid phase for temperatures and pressures which correspond to densities larger than 1.15 times the critical density. Based on a rigorous assignment of the signals detected in this work, the slow and fast diffusivities could be associated with the Fick and thermal diffusivities. For all other thermodynamic states, a single hydrodynamic mode or signal was obtained experimentally. With the help of theoretical Rayleigh ratios as well as from the general behavior of the diffusivities as a function of temperature and pressure, the signals were identified to be related to the Fick diffusivity in the supercritical state and to a mixed diffusivity in the gas state and the saturated vapor phase. The results are discussed in connection with the behavior of the diffusivities along certain paths in the pressure–temperature projection of the phase diagram of the mixture. [ABSTRACT FROM AUTHOR]

The Bi0.5Li0.5ZrO3 and CaZrO3 co-modified (K,Na)NbO3-based ceramics, with a formula of (0.98-x)K0.4Na0.6NbO3-xBi0.5Li0.5ZrO3-0.02CaZrO3, were designed to form a rhombohedral-tetragonal phase boundary, and a conventional solid-state sintering method was employed to prepare them. X-ray diffraction analysis revealed that a pure perovskite structure could be maintained in the studied composition range 0 ≤ x ≤ 0.05. Dielectric-temperature measurements were performed to further identify the phase structure of the ceramics, which was found undergoing a gradual evolution from an orthorhombic to a rhombohedral structure with increasing x. Furthermore, a rhombohedral-tetragonal phase boundary was observed to be formed at x = 0.035, near which enhanced piezoelectric properties were obtained, with piezoelectric constant d33 = 241 pC/N and planar electromechanical coupling coefficient kp = 0.37. Additionally, an investigation was conducted of the influence of Bi0.5Li0.5ZrO3 addition on the microstructure and paraelectric-ferroelectric phase transition of the ceramics as well. We believe that the findings in this current work can deepen our understanding of the role of Bi0.5Li0.5ZrO3 in the construction of a phase boundary and improvement of piezoelectric properties for (K,Na)NbO3-based ceramics. [ABSTRACT FROM AUTHOR]

It is established that 82% of the vapor can condense into the liquid phase when calcium is evaporated from an alloy with copper at low pressures of 0.7–1.33 kPa under nonequilibrium conditions. Based on values of the vapor pressure of calcium and copper determined using the boiling point approach, a complete diagram of state is constructed that includes the condensed and vapor phases at atmospheric pressure and in vacuums of 0.7 and 1.33 kPa. The temperatures of boiling and the composition of the condensate are calculated from the boundaries of the melt–vapor phase transitions. The condensate is represented by calcium with a copper content no greater than 3.95 × 10–2 wt % and a boiling point 77–129°С higher than the melting point of Ca. It is assumed that the condensate remains in the molten state. The fundamental possibility of a liquid–vapor–liquid process that can be applied to distillation for the production of calcium is thus proved. [ABSTRACT FROM AUTHOR]

Abstract The cubic-plus-association equation of state was applied to model the phase behaviour of bitumen/ n -alkane systems including saturation pressures, liquid-liquid boundaries, yields, and phase compositions. Yield is defined here as the mass of bitumen in the heavy phase divided by the mass of bitumen in the feed. To implement the model, the bitumen was divided into a set of pseudo-components based on a distillation assay and either the n -pentane insoluble content of the oil (CPA-C5 approach) or the propane insoluble content (CPA-C3 approach). The pseudo-components in the solvent insoluble part of the oil were defined as self-associating components, all other pseudo-components were non-associating. The critical properties and acentric factor for each pseudo-component were determined from established correlations. A set of CPA parameters was then developed to fit the available phase behavior data. The self-associating pseudo-components were assigned a distribution of self-association energies in order to capture the sequential partitioning of asphaltenes to the heavy phase upon solvent addition or in different solvents. Both approaches matched the phase behavior data for mixtures of bitumen with n -pentane and higher carbon number n -alkanes almost to within the experimental error. The CPA-C3 approach also matched the phase behavior data for mixtures of propane and bitumen. The CPA-C5 approach could not match the yield data for propane diluted bitumen but was more straightforward to implement and was less computationally intensive because it employed fewer self-associating components. To apply either approach to another oil, only the self-association energy of the self-associating pseudo-components need be adjusted. The cross-association energy between the solvent and the self-associating pseudo-components must be tuned for any new solvent. [ABSTRACT FROM AUTHOR]

The structural transformation of thin-plate pearlite in the cold plastic deformation (drawing) of C86D steel coils with total reduction up to 83.2% is considered. In terms of the physical mesomechanics of structurally heterogeneous media, it is shown that the ferrite–cementite phase boundaries play a significant role in the localization of the deformation and the formation of fragmented mesostructure at different degrees of cold plastic deformation. The transformation of cementite in cold dynamic spheroidization is shown to be associated with the fragmentation of plates and the formation of local submicrocrystalline sections in the pearlite. [ABSTRACT FROM AUTHOR]

Abstract New lead-free piezoelectric ceramic system based on (1- x) (K 0.4 Na 0.6) Nb 0.96 Sb 0.04 O 3 - x Ba 0.1 (Bi 0.5 Na 0.5) 0.9 ZrO 3 was designed and fabricated by using conventional ceramic processing techniques. An investigation was carried out with a focus on the effects of Ba 0.1 (Bi 0.5 Na 0.5) 0.9 ZrO 3 content on the phase structure, dielectric and piezoelectric properties of the ceramics. It was found that adding Ba 0.1 (Bi 0.5 Na 0.5) 0.9 ZrO 3 could move the rhombohedral-orthorhombic phase transition temperature upwards and simultaneously shift the orthorhombic-tetragonal phase transition temperature downwards, and thereby resulted in the formation of a rhombohedral-tetragonal phase boundary with 0.045 ≤ x ≤ 0.05. The piezoelectric properties were obviously enhanced for the ceramics with compositions near the rhombohedral-tetragonal phase boundary. Furthermore, an analysis was as well conducted on the main characteristics of the ferroelectric-paraelectric phase transition of the ceramics. Our experimental results suggest that the Ba 0.1 (Bi 0.5 Na 0.5) 0.9 ZrO 3 is an effective additive for the construction of phase boundaries in (K,Na)NbO 3 -based ceramics, therefore benefiting the improvement of piezoelectric activity. Highlights • Lead-free (1-x) (K0.4Na0.6) Nb0.96Sb0.04O3-xBa0.1(Bi0.5Na0.5) 0.9ZrO3 ceramics. • A solid solution system with a rhombohedral–tetragonal phase boundary. • Main features of their ferro-paraelectric phase transition have been analyzed. • Investigating the relationship between composition, structure and properties. [ABSTRACT FROM AUTHOR]

To achieve an effective design of additively manufacturable Ni superalloys with decent service performance, a hybrid computational design model has been developed, where the strategy to tailor local elemental segregations was integrated within a scheme of minimizing the cracking susceptibility. More specifically, the phase boundary of primary NbC / γ matrix was introduced into the design routine to tune the spatial distribution of critical solutes at an atomic scale, thereby inhibiting the formation of borides and segregation-induced cracking. Based on the output of the design, new grades of Ni superalloy have been developed with excellent additive manufacturability, as confirmed by the robustness of printing parameters in fabricating low-defect-density samples. The capability of the phase boundaries to evenly distribute boron atoms was validated experimentally, and the cracking induced by uncontrolled boron segregation at grain boundaries was effectively prevented. The newly designed alloys showed good tensile properties and decent oxidation resistance at different service temperatures, which are comparable to those of conventionally produced superalloys. The finding that phase boundaries can be employed to prevent undesirable clustering of boron atoms can be extended to manipulate the distributions of other critical elements, which provides a new path for designing novel Ni superalloys with balanced printability and mechanical properties. [Display omitted] [ABSTRACT FROM AUTHOR]

• A seed-induced strategy is adopted to construct MoSe 2 /ZnSe-NC@NC nanotube. • The heterostructure of MoSe 2 /ZnSe promote the high-rate Na+/K+ storage. • Kinetic analyses and DFT calculation reveal the improved electrochemical kinetics. • The Na+/K+ storage mechanism is confirmed by ex-situ Raman and XRD results. It is a challenge to construct suitable hosts for the large-sized Na+/K+ to overcome the hampered reaction kinetics for the energy storage. Component regulation and ingenious structure design are significant for achieving high electrochemical performance in Na+/K+ ions batteries (SIBs/PIBs). Herein, though a seed-induced assembly and subsequent high-temperature selenization process, MoSe 2 /ZnSe nanotubes encapsulated in N-doped carbon (NC) framework (MoSe 2 /ZnSe-NC@NC) are rationally synthesized. In this MoSe 2 /ZnSe-NC@NC structure, there are abundant heterointerfaces, which can induce to form self-built electric field and increase the interfacial Na+/K+ storage, promoting charge transfer and accelerating reaction kinetics. This leads to enhance Na+/K+ storage performance in terms of high reversible capacity, superior rate performance and long term cycling stability. Simultaneously, MoSe 2 /ZnSe-NC@NC exhibits impressive electrochemical properties, including high rate capability of 236.3 mAh g−1 at high current denisity of 5.0 A g−1 for SIBs and stable capacity of 162.4 mAh g−1 at 0.2 A g−1after 500 cycles for PIBs. Moreover, high energy density of 121.2 Wh kg−1 at power densities of 11486.3 W kg−1 can be also obtained in MoSe 2 /ZnSe-NC@NC//Na 3 V 2 (PO 4) 3 /C full cell, demonstrating a promising anode candidate for large-sized Na+/K+ storage. [ABSTRACT FROM AUTHOR]

The eutectic high-entropy alloys have shown promising mechanical behaviors while their softening at elevated temperatures is still a challenge. Generally, the boundaries are the weak parts to be strengthened with increased temperatures in eutectic high-entropy alloys. Here, we found that the minor addition of boron in Ni 30 Co 30 Cr 10 Fe 10 Al 18 W 2 eutectic high-entropy alloy can significantly strengthen the FCC grain boundaries and the FCC/B2 phase boundaries at elevated temperatures. A remarkable tensile yield strength over 581 MPa with elongation of 71 % at 800 °C is achieved with minor boron addition, corresponding to a 45 % increase in yield strength and 129 % improvement in ductility compared with the boron-free counterpart. Accompanied by the boron-strengthened phase boundary, sustainable dynamic recovery occurs in the FCC and B2 phases during high-temperature tensile testing, ensuring excellent ductility. Moreover, the benchmark test indicates that the strengthening effect of boron and borides on the boundaries contributes up to 166 MPa to the yield strength of eutectic high-entropy alloy at 800 °C. These findings shed light on the development of high-temperature eutectic high-entropy alloys with a microalloying strategy. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of high-voltage LiCoO 2 (LCO) is crucial for achieving lithium-ion batteries with a high volumetric energy density. However, LCO experiences accelerated degradation at high voltages due to severe interface and structure instability. A uniform and robust cathode-electrolyte interphase (CEI) serves as a vital barrier for protecting the interface. However, the smooth surface of single-crystalline LCO, lacking grain boundaries, poses challenges in generating an effective CEI. Herein, ZrO 2 nano-rivets are constructed on the surface of LCO to provide phase boundaries for preferential film-forming sites, inducing the formation of a uniform and robust CEI. The high-quality CEI derived from ZrO 2 nano rivets stabilizes the fragile surface of high-voltage LCO and facilitates lithium-ion diffusion. In addition, a Zr diffusion layer is simultaneously built in the LCO bulk. Zr diffusion into the LCO lattice not only effectively suppresses unfavorable phase transitions to stabilize the bulk structure, but also mitigates oxygen charge deficiencies at the highly delithiated state, therefore stabilizing lattice oxygen. Consequently, the modified LCO exhibits excellent capacity retention of 80% after 700 cycles at 4.6 V. This work emphasizes the significance of material surface properties in CEI formation and provides new insights for the design of CEI. [Display omitted] • ZrO 2 nano-rivets are constructed on LiCoO 2 surface to provide phase boundaries to induce the formation of uniform CEI. • The high-quality CEI stabilizes the fragile surface of high-voltage LiCoO 2 and facilitates lithium-ion diffusion. • Zr diffuses into the LiCoO 2 lattice which effectively suppresses unfavorable phase transitions and mitigates oxygen charge deficiencies. [ABSTRACT FROM AUTHOR]

The ratio of the number of intra- and interphase crosslinks in the mixtures of nitrile-butadiene rubber with different content of acrylonitrile units and polyvinyl chloride was estimated from the contribution of each phase to the tensile modulus. It is shown that the number of chemical bonds between the components has a decisive effect on ozone-protective effect by a thermoplastic. The degree of crosslinking of rubber does not matter. [ABSTRACT FROM AUTHOR]

Time‐resolved X‐ray diffraction measurements have been carried out on dynamically compressed Sn up to a maximum pressure of ∼13 GPa at the European Synchrotron Radiation Facility. The phase transition from β‐Sn to body‐centered tetragonal (b.c.t.) Sn has been observed using synchrotron X‐ray diffraction for the first time undergoing shock compression and release. Following maximum compression, the sample releases to lower pressures for several nanoseconds until the reverse transition occurs. The data are in good agreement with previous shock boundaries that indicate that the β‐Sn phase is stable ∼2 GPa higher than the static boundary upon compression and the b.c.t.‐Sn phase is stable ∼1 GPa lower upon release. The transition to the high‐pressure phase reveals a loss of texture in the X‐ray diffraction data from the 'quasi' single‐crystal β‐Sn structure to a more powder‐like Debye–Scherrer ring. Time‐resolved X‐ray diffraction measurements were carried out on dynamically compressed Sn at the ID09 beamline of the European Synchrotron Radiation Facility. Using an infra‐red laser (up to 180 mJ at 1064 nm) with a 5 ns Gaussian pulse shape, the high‐pressure β‐Sn to b.c.t.‐Sn phase transition was observed using a single X‐ray bunch from the synchrotron. [ABSTRACT FROM AUTHOR]

Adsorption of Co, Mn, and Fe atoms on the surface of calcite in ultrahigh vacuum and the interaction of the generated adsorption systems with water were studied by X-ray photoelectron spectroscopy. It is demonstrated that Mn and Fe atoms form CaCO3/Mn(Fe)CO3 solid solutions on calcite surface, whereas the dominant compounds of adsorbed Co atoms are CoО and Co3О4. When interacting with water, the Mn and Fe surface compounds are not appreciably modified, whereas the Co compounds are partly transformed into soluble hydroxylated complexes. [ABSTRACT FROM AUTHOR]

Abstract Developing anode materials that have high safety and high performance is essential for their application in Li ion batteries. Ternary phase Li 4 Ti 5 O 12 /rutile/anatase (N-LTO/A/R) nanocomposites that have abundant phase boundaries and structure defects are prepared via solvothermal synthesis and following calcination under an Ar/NH 3 atmosphere. With the introduction of multiple phases and defects, the as-prepared ternary phase nanocomposites display excellent lithium storage capability in a Li half-cell as well as in full-cell batteries. The nanocomposites deliver a reversible specific capacity of 149.0 mAh g−1 at a current density of 10 A g−1 and maintain about 85% of the specific capacity after 800 cycles at a higher rate of 5 A g−1 for the Li half-cell. Even in the Li ion full-cell, the as-prepared nanocomposites deliver specific capacities of 210 and 124 mAh g−1 at current densities of 0.05 and 1 A g−1, respectively. The extraordinary electrochemical performance of the N-LTO/A/R nanocomposites is attributed to the nanostructures, phase boundaries, presence of structure defects, and larger specific surface area, which favor facilitating lithium ion diffusion and electron transfer. This study shows that the ternary phase nanocomposites are very promising as a high-performance anode in lithium ion batteries. Highlights • Li 4 Ti 5 O 12 /anatase/rutile with structural defects prepared by NH 3 /Ar atmosphere. • Superior rate performance and cycle stability in Li-ion half-cell and full-cell. • Performance enhanced by the combination of phase boundaries and defects. [ABSTRACT FROM AUTHOR]

The possibilities of increasing the interaction between the components of previously developed thermoplastic vulcanisates based on polypropylene and a combination of isoprene and nitrile butadiene rubbers were studied. The morphology of the composites was recorded by means of optical microscopy using an analytical complex based on a Leica DM-2500 optical microscope, a Leica DFC-420C digital high-resolution colour camera with a Peltier cooling system, and a specialised computer desk. The parameters of crystallisation of polypropylene were measured by differential scanning calorimetry using a DSC 204F1 Phoenix instrument (Netzsch). The physicomechanical properties of the vulcanisates were also determined. Maleinised polypropylene, a copolymer of ethylene with vinyl acetate, and their mixtures were used as compatibilising additives. Maleinised polypropylene was introduced together with polypropylene in a quantity of 1-10 parts; no changes in properties were observed with increase in the dosage above 4 parts, so this dosage was used. The copolymer of ethylene with vinyl acetate (1-10 parts) was introduced into the rubber phase at the stage of rubber mix preparation specially to improve the compatibility of polypropylene and nitrile butadiene rubber. The introduction of maleinised polypropylene leads to an increase in the workability and in the level of elastic strength properties, in particular the tensile elastic modulus and hardness. A considerable increase in the uniformity of distribution of components throughout the volume, a finer dispersion of the rubbers in the polypropylene matrix, and a reduction in the number of pores in the material were shown, and also an increase in the degree of polypropylene crystallinity measured under experimental conditions. The most positive effect is observed with the combined introduction of the copolymer of ethylene with vinyl acetate and the maleinised polypropylene: the nominal stress under elongation increases by 34%, and the elongation at break by 15%. The combined introduction of the compatibilising additives improves the compatibility of the components of the system, the phase boundaries become more diffuse, there is a reduction in the optical density of rubber-rich zones, and these zones are penetrated by polypropylene fibrils. [ABSTRACT FROM AUTHOR]

For TA15 titanium alloy, slip is the dominant plastic deformation mechanism because of relatively high Al content. In order to reveal the grain-scale stress field and geometrically necessary dislocation (GND) density distribution around the slip traces and phase boundaries where the slip lines are blocked due to Burgers orientation relationship (OR) missing. We experimentally investigated tensile deformation on TA15 titanium alloy up to 2.0% strain at room temperature. The slip traces were observed and identified using high resolution scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) measurements. The grain-scale stress fields around the slip traces and phase boundaries were calculated by the cross-correlationbased method. Based on strain gradient theories, the density of GND was calculated and analyzed. The results indicate that the grain-scale stress is significantly concentrated at phase/grain boundaries and slip traces. Although there is an obvious GND accumulation in the vicinity of phase and subgrain boundaries, no GND density accumulation appears near the slip traces. [ABSTRACT FROM AUTHOR]

High entropy alloys present opportunities to develop new materials with unique mechanical properties. Through careful selection of constituent elements and thermal processing, different microstructures with varying properties can be achieved. This study is focused on an interesting class of high entropy alloys with dual phase microstructure, a soft FCC and a hard BCC phase. Specifically, the local material response of Al 13 CoCrFeNi (atomic %), at the microscale and in the vicinity of phase boundaries, is analyzed using high resolution strain and grain orientation measurements. Different heat treatments resulting in varying phase volume fractions and deformation temperatures were considered. The local response of this high entropy alloy displayed significant heterogeneity in plastic strain accumulation with preferential accumulation in the FCC grains and localizations at phase boundaries. The preferential accumulation of plastic strains in FCC grains (33–85% higher than BCC) was further enhanced with very high temperature heat treatments conducted at 1300 °C. These changes in plastic strain partitioning were associated with the increase in BCC phase volume fraction which was altered during heat treatment. At the macro-scale, the unloading response of Al 13 CoCrFeNi revealed a nonlinear unloading behavior with large magnitudes of recoverable strains (0.9–1.4%). Deformation at cryogenic temperatures revealed slip dominated plasticity and no changes in the underlying deformation mechanism due to temperate reduction. However, the plastic strain partitioning between the FCC and BCC phases is shown to be affected with larger magnitudes of plastic strains accumulating in the FCC phase, and less in the BCC phase, compared to the room temperature deformation response. [ABSTRACT FROM AUTHOR]

CO2 Reduction Reaction In article 2203506, Lin Gu, Xiao Li, Hong Liu, Weijia Zhou, and co‐workers aim to solve the problems of poor CO2 adsorption capacity and weak *H supply capacity in Cu‐Sn alloys, by designing SnO2/Cu6Sn5/CuO nanocatalysts with superscalar phase boundaries. This strategy of tandem electrocatalytic CO2 reduction reaction (CO2RR) with multiple active sites reduced the reaction barrier in the CO2 reduction process, resulting in excellent CO2RR activity and high selectivity of formic acid. [ABSTRACT FROM AUTHOR]

Ti-based nanoplates with abundant phase boundaries have been synthesized via partial lithiation reaction and optimized heat treatment. Using phase boundaries (rather than free surfaces) to keep the crystalline domains small might have significant advantages, such as improved tap density (therefore volumetric energy density) and reduced loss of live Lithium to the solid electrolyte interphase (SEI) which only coats the free surfaces. As lithium ion battery anode, the obtained Li 4 Ti 5 O 12 /TiO 2 (Anatase)/TiO 2 (Rutile) three-phase mixture shows a capacity of about 170 mA h g −1 at 4000 mA g −1 (fully charged in ~150 s), and undergoes more than one thousand cycles with capacity fade of only 0.02% per cycle. It also demonstrates excellent cycling stability even after 4000 cycles at 500 mA g −1 in a Li-matched full cell vs. LiFePO 4 cathode in large pouch cell format, with tolerable gassing behavior. Rather than relying on Ti 3+ defects or excessively large surface area, the present material is prepared in fully oxidizing environment, with abundant phase boundaries as the main capacity enhancement mechanism, which simplify its industrial production. [ABSTRACT FROM AUTHOR]

The subsolidus equilibrium phase diagrams of Ti–V, Ti–Nb and Ti–Ta alloys have been computed through cluster expansion, lattice dynamics and Monte Carlo modeling methods combined with Density Functional Theory total-energy calculations. Computed phase boundaries in Ti–V alloy are found to be in good agreement with reported CALPHAD assessed experimental boundaries. For Ti–Ta system, the computed phase boundaries agree well with CALPHAD boundaries for Ta-rich alloys. For Ti-rich alloys, the transformation temperatures are overestimated by up to 200 K. In the case of Ti–Nb system, the calculated boundary of the bcc-solid-solution phase decreases rapidly in temperature with increasing Nb concentration compared to CALPHAD boundary, deviating from the latter by up to 600 K at 80% Nb. Our calculation gives qualitatively correct hcp-solid-solution regions for all the three alloy systems (i.e., solubility of V/Nb/Ta in hcp Ti). A key difficulty in modeling these systems is the presence of mechanical instability in the bcc phase at high Ti concentration. In this work, we circumvent this difficulty by excluding structures exhibiting instability in the cluster expansion construction process. We find that, while such a scheme is often appropriate (as in the Ti–V and Ti–Ta systems), it can become unreliable when the result exhibit a too strong sensitivity to the exclusion rule used (as in the Ti–Nb system). In all systems, we find that the inclusion of lattice vibration effects is crucial to obtain even qualitative agreement with experiment. [ABSTRACT FROM AUTHOR]

The binary manganese-antimony (Mn-Sb) phase diagram was reinvestigated in the whole composition range using powder-XRD, DTA and SEM-EDX. The phase boundaries and melting temperatures of the ferromagnetic phases MnSb and MnSb were modified by taking into account the new experimental data. Most of the reaction temperatures could be verified within a range of ±10 °C. Nevertheless, a few temperatures had to be revised, such as the eutectic reaction L → β- Mn + Mn Sb at 893 °C and the eutectoid reaction β- Mn → α- Mn + Mn Sb at 718 °C. The previously reported peritectic melting behavior of MnSb could be confirmed. The variation of the lattice parameters of the NiAs-( B8 ) type MnSb phase with composition was determined. A revised version of the of the Mn-Sb phase diagram is presented. [ABSTRACT FROM AUTHOR]

We generalize the classical Legendre-Hadamard conditions by using quadratic extensions of the energy around a set of two configurations and obtain new algebraic necessary conditions for nonsmooth strong local minimizers. The implied bounds of stability are easily accessible as we illustrate on a nontrivial example where quasiconvexification is unknown. [ABSTRACT FROM AUTHOR]

For designing new and improved materials, predictive modeling of precipitation and segregation kinetics is required. So far, no modeling approach is available that couples precipitation with ab initio segregation data. We derive the mathematical basis for a model to describe segregation and precipitation kinetics with grain boundary segregation energies obtained from ab initio simulations. The model is implemented rigorously and validated with experimental data on a Fe-Au system from literature. [Display omitted] [ABSTRACT FROM AUTHOR]

The nonuniformity of hot plastic deformation of 08X21H5T steel is studied. Tensile tests are conducted in the vacuum chamber of the IMASH-20-75 Ala-Too machine. The samples are attached to a clamp in the chamber by means of straps. A junction of a platinorhodium-platinum thermocouple is soldered to the side surface of the sample. Air is pumped out of the chamber to a residual pressure of 5.0 × 10 mm Hg (6.7 × 10 Pa). The sample is heated to 800-1200°C by means of industrial-frequency current. The precision of temperature maintenance is ±5°C. The deformation of the austenite and ferrite phases is investigated as a function of the overall deformation of the steel and the temperature. The influence of these factors on the slip rate of the austenite and ferrite phases along the grain boundaries is also considered. The hot-microhardness ratio of the austenite and δ ferrite in 08X21H5T steel is investigated as a function of the temperature. [ABSTRACT FROM AUTHOR]

Tuning the lattice degree of freedom in nanoscale functional crystals is critical to exploit the emerging functionalities such as piezoelectricity, shape-memory effect, or piezomagnetism, which are attributed to the intrinsic lattice-polar or lattice-spin coupling. Here it is reported that a mechanical probe can be a dynamic tool to switch the ferroic orders at the nanoscale multiferroic phase boundaries in BiFeO3 with a phase mixture, where the material can be reversibly transformed between the 'soft' tetragonal-like and the 'hard' rhombohedral-like structures. The microscopic origin of the nonvolatile mechanical switching of the multiferroic phase boundaries, coupled with a reversible 180° rotation of the in-plane ferroelectric polarization, is the nanoscale pressure-induced elastic deformation and reconstruction of the spontaneous strain gradient across the multiferroic phase boundaries. The reversible control of the room-temperature multiple ferroic orders using a pure mechanical stimulus may bring us a new pathway to achieve the potential energy conversion and sensing applications. [ABSTRACT FROM AUTHOR]

Complexing between soy proteins (SP) and gum arabic (GA) was achieved by mutual titration of soy protein and gum arabic and was characterized using isothermal titration calorimetry (ITC), turbidity, sedimentation and ternary phase boundaries. In the first section, SP were titrated into GA (SP-to-GA titration) under salt-free condition (no added NaCl) at pH 3.0 and pH 5.6, respectively. ITC experiments displayed exothermic processes at both pH status, but the enthalpy changes (Δ H ) at pH 3.0 was −0.70 ± 0.02 cal/g as compared to −0.10 ± 0.01 cal/g at pH 5.6. For SP-to-GA titration at pH 3.0, a sudden turbidity increase was observed at the critical SP/GA mass ratio ( r φ ) of 0.42, which was approximately equal to the charge density ratio of GA and SP (0.36), indicating the charge compensation was achieved at phase separation point. In the second part, GA was titrated into SP (GA-to-SP titration) under salt-free condition at pH 3.0. An immediate turbidity increase was observed when GA was added into SP, while the sedimentation ratio measurement showed that the complex was unstable only in the GA/SP mass ratio range of 0.3–0.6. The ITC result showed a much higher Δ H than that for SP-to-GA titration. Effect of NaCl concentration on the complexing behavior by SP-to-GA titration at pH 3.0 was studied in the last. Δ H s and binding isotherms changed monotonically with the increase of salt concentration from 0 to 250 mM. However, turbidity measurement and phase boundaries revealed that the maximum phase separation was obtained at salt concentration of 100 mM. [ABSTRACT FROM AUTHOR]

[Display omitted] The CSL/DSCL model for interfaces in crystalline materials offers a unified framework to study interface dislocations in phase boundaries and disconnections in grain boundaries. The model relies on the existence of a coincidence relation between the two lattices that meet at an interface. The model's ability to quantitatively predict the thermodynamics and kinetics of interfaces has been demonstrated for a limited set of symmetric tilt grain boundaries (STGBs) in cubic materials and twin boundaries. However, the lack of a general framework of interface defects prevents its applicability to arbitrary rational boundaries. In this paper, we present a mathematical framework based on the Smith normal form (SNF) for integer matrices to study the bicrystallography of rational phase and grain boundaries. One of the main results of the paper is a constructive proof of the invariance of the coincident site lattice (CSL) under discrete relative displacements of the parent lattices (of possibly different kind) by a displacement shift complete lattice (DSCL) vector. In addition, we obtain necessary and sufficient conditions on two lattices, related by not only rotations but also lattice distortions, for the existence of a coincidence relation. We first apply these results to explore coincidence relations in arbitrary phase boundaries, and study interface dislocations. In particular, we demonstrate the framework for a phase boundary formed by a strained hexagonal lattice and a square lattice. As a second application, we show how to enumerate all possible (geometric) disconnection modes in arbitrary rational grain boundaries, including glide and non-glide modes in both STGBs and asymmetric-tilt grain boundaries (ATGBs). The constructive nature of the framework lends itself to an algorithmic implementation based exclusively on integer matrix algebra to construct all interfaces that admit CSLs up to a prescribed size, and determine disconnection modes in grain boundaries. We demonstrate the use of SNF bicrystallography on selected bicrystal misorientation axes/angles in face-centered cubic (fcc), body-centered cubic (bcc), and hexagonal (hex) lattices. [ABSTRACT FROM AUTHOR]