Search

Simultaneously enhancing the strength, plasticity, and toughness of metal materials has been a prominent research objective. In this study, the precipitation of nano-scale vanadium carbide particles at a lower tempering temperature is controlled to achieve three key benefits: reducing lattice distortion in bainitic ferrite, strengthening through precipitation, and enhancing the toughness of bainitic ferrite, while also maintaining the content and stability of retained austenite. The adopted procedure increases the comprehensive mechanical properties of steel by 17%. In particular, the room-temperature impact toughness is increased by 41%. This comprehensive microstructure optimization endows bainitic steel with an excellent combination of mechanical properties. [ABSTRACT FROM AUTHOR]

With the rapid development of broadband transducers, there is an increasing demand for enhanced electromechanical properties in lead-free piezoelectric ceramics. In this study, the strategies to enhance the electrical properties of ceramics were explored by doping BaZrO 3 into 0.96(K 0.48 Na 0.52)Nb 0.96 Sb 0.04 O 3 -0.04(Bi 0.5 Ag 0.5)ZrO 3 ceramics, inducing lattice distortion (c / a) and regulating the phase structure. The ceramics doped with 1.5 mol% BaZrO 3 demonstrate excellent electrical performance, with a piezoelectric coefficient (d 33) of 545 pC/N, a relative dielectric constant (ε r) of 4126, and an electromechanical coupling factor (k p) of 54.1 %. The reduced c / a ratio and rhombohedral-orthorhombic-tetragonal phase structure reduce the polarization energy barrier and promote the ordered arrangement of ferroelectric dipoles, thereby enhancing the comprehensive performance of the ceramics. Lastly, the electrical impedance of ceramics is studied in detail and reveals the main conduction mechanism in the microscopic region. This research provides new insights into optimizing the electrical properties of ceramics through microstructural manipulation and demonstrates the potential application of KNN-based ceramics in high performance piezoelectric transducers. [ABSTRACT FROM AUTHOR]

The internal modification with rare earth ion doping proved to be a very effective strategy for improving the luminescent properties of NaYF 4 -based upconversion materials. However, greatly enhancing the luminescence efficiency of NaYF 4 :Yb3+/Er3+ remains a major challenge. Herein, the effects of Sn4+ doping on the structure and luminescent performance of such material were explored. The hydrothermal molten-salt method was applied to synthesize the Sn4+-doped NaYF 4 :Yb3+/Er3+ upconversion materials, and their crystal structures, morphologies, surface chemical composition and element states, and luminescence performance were characterized. It was found that Sn4+ doping can significantly enhance the luminescence intensity and tailor the chromaticity of NaYF 4 :Yb3+/Er3+. In particular, the green (G) and red (R) luminescence intensity levels of the 30 mol% Sn4+ doped material were increased by factors of 26.97 and 38.91, respectively. The R/G ratio was incremented from 0.34 for the undoped material to 0.83 for the 40 mol% Sn4+ doped counterpart. The Sn4+ doping led to the change of lattice distortion and crystal growth pattern of NaYF 4 :Yb3+/Er3+. The mechanism for Sn4+ doping to affect the luminescence properties of the prepared upconversion material was also explored. The changes in luminescence intensity levels and R/G ratios could be attributed to the highly asymmetric distorted lattice and crystal field resulting from Sn4+ doping. [ABSTRACT FROM AUTHOR]

In the present study, we optimized the fabrication process, characterized the microstructures and evaluated the mechanical properties of a high entropy carbide ceramic with novel composition, (HfNbTaTiW)C. Our results show that 1700 °C carbon thermal reduction (CTR) and 1800 °C spark plasma sintering (SPS) can yield a single phase (HfNbTaTiW)C with high relative density, low residual C/O and fine grain structure. The nanohardness of (HfNbTaTiW)C is on the lower end (28.16 GPa), but its fracture toughness (4.84 MPa m1/2) is superior to both its constituent monocarbides and most existing multi-cation transition metal carbides. The lattice distortion, bonding strength and stacking fault energy of (HfNbTaTiW)C are compared with (HfNbTaTiZr)C through First Principle Calculations to help understand the observed mechanical properties. The results indicate first, the reduced bonding strength contributes more importantly than the large lattice distortion to the hardness, leading to the observed low hardness of (HfNbTaTiW)C and second, the reduced bonding strength and low intrinsic stacking fault energy synergistically contribute to the observed high toughness of (HfNbTaTiW)C. [ABSTRACT FROM AUTHOR]

In this study, varying amounts of MnO2 up to 5 wt.% were added to magnesium aluminate spinel (MA) bodies using a solid‐state sintering method at 1200–1600°C. The effect of MnO2 addition on the phase composition, microstructure, distribution of elements, and ionic valence of MA was investigated via X‐ray diffraction, scanning electron microscopy, energy‐dispersive spectroscopy, and X‐ray photoelectron spectroscopy, respectively. The results showed that Mg2+ ions in MA crystals were replaced by Mn2+ ions, resulting in the formation of the (Mg1‐xMnx)Al2O4 solid solution. The distorted crystal structures promoted the sintering reactions, and the mechanical characteristics of MA were greatly improved by the solid solution strengthening process. When the additive amount of MnO2 was 5 wt.% and the sintered temperature reached at 1600°C, excess manganese ions hardly dissolved into the lattice of MA. And these ions were only distributed at the grain boundaries of MgAl2O4, forming a “barrier” that hindered the migration and diffusion of particles, thereby suppressing the sintering process and weakening the mechanical strength of MA. [ABSTRACT FROM AUTHOR]

A novel synergistic strategy was used to improve the piezoelectric characteristics of high-temperature piezoelectric ceramics. This work combined three commonly used strategies, constructing the Morphotropic Phase Boundary to reduce energy barriers, changing domain structures impacting macroscopic piezoelectric properties, and adjusting BO 6 octahedral distortions reflecting microstructural changes, thus effectively regulating the piezoelectric behaviors of BiFeO 3 -based ceramics. As a result, the 0.67BiFeO 3 -0.32BaTiO 3 -0.01BiAlO 3 component, exhibiting the maximum distortion of the BO 6 octahedron and the coexistence of macrodomains and nanodomains, achieved the optimal piezoelectric characteristics (d 33 = 225 ± 10 pC N−1, T C = 450 °C). Additionally, the ceramic maintained its high piezoelectric properties even at temperatures as high as 280 °C (346 pC N−1). This study presents a novel collaborative design strategy that combines phase structure, domain structure, and BO 6 octahedral distortion, significantly enhancing the development potential of lead-free high-temperature piezoelectric materials in the future. [ABSTRACT FROM AUTHOR]

Near‐infrared (NIR) phosphors have been widely used in biomedical applications based on their deep tissue penetration. However, the lack of blue‐pumped NIR phosphors with emission ranges beyond 1000 nm has greatly limited the development of NIR phosphor‐converted light‐emitting diodes (pc‐LEDs). Herein, a facile way to boost the luminescence efficiency and thermal stability by introducing the promoters of Ce3+ and Na+ into Nd3+‐doped SrS NIR phosphor is demonstrated, thus achieving light emitting at 850–1500 nm with a peak wavelength of ≈1070 nm. Through sensitization by the allowed 4f → 5d transition of Ce3+, the SrS: Nd3+ phosphors are excitable by using a commercial blue LED, attributing to the effective energy transfer between Nd3+ and Ce3+. Besides, the structural analysis and density functional theory calculations reveal the lattice distortion mechanism and geometry of doping ions contributed to the weakened thermal quenching effect and the increasing of internal quantum efficiency. The optimized NIR phosphor luminescence intensity remains at 91.8% of the initial intensity at 393 K, and the internal quantum efficiency increases to 42.8% from 31.7% of the sample without Na+ doping. The present exploration of Nd3+‐doped NIR phosphors will provide a reference for designing NIR pc‐LEDs with enhanced properties. [ABSTRACT FROM AUTHOR]

High Q (Hf1−xSnx)O2 ceramics were prepared via a standard solid‐state reaction route, and the microwave dielectric characteristics were investigated systematically together with the structure evolution. With increasing x, the structure changed from HfO2 (monoclinic in space group P21/c, x = 0 and 0.03) to Hf0.77Sn0.23O2 (orthorhombic in space group Pbcn, x = 0.23), while the two‐phase structure: HfO2 major phase and Hf0.77Sn0.23O2 secondary phase, was determined for x = 0.05–0.21, and Hf0.77Sn0.23O2 major phase combined with SnO2 tetragonal secondary phase in space group P42/mnm was confirmed for x = 0.30–0.40. The Qf value was significantly increased from 24,500 to 167,650 GHz by Sn‐substitution, and the best combination of microwave dielectric characteristics was obtained in Hf0.77Sn0.23O2 ceramics: εr = 17.2, Qf = 167 650 GHz at 9.6 GHz and 230 710 GHz at 26.1 GHz, and τf = −52.6 ppm/°C. The dielectric loss was deeply linked with the structure stability and lattice‐distortion. Also, the phase composition, the bond strength, as well as the degree of covalency, had a tight connection with dielectric loss. The present ceramics were expected to be the promising candidates as low‐εr microwave dielectric ceramics. [ABSTRACT FROM AUTHOR]

Traditional piezoelectric materials cause serious environmental and health issues because of their lead–containing substances, and thus lead–free piezoelectric ceramics would have many applications. In this study, we successfully prepared the lead–free ceramics (1- x) (K 0 · 48 Na 0 · 48 Li 0.04) (Nb 0 · 975 Sb 0.025)O 3 – x (Bi 0 · 5 Na 0.5) (Zr 0 · 8 Ti 0.2)O 3 ((1- x)KNLNS– x BNZT, x = 0, 0.005, 0.0075, 0.01, 0.015, 0.02 and 0.03) with rhombohedral–tetragonal (R–T) phase coexistence near room temperature, employing con–entional solid sintering. The minimum cell volume of the ceramics and R–T phase coexistence in them were achieved at a doping amount x = 0.01, which facilitated the optimal performance of the ceramics (d 33 ∼467 pC/N ± 14 pC/N, T c∼272 °C, ε r ∼1676, k p ∼0.42, where d 33 : piezoelectric constant; T c: Curie temperature; ε r : dielectric constant; k p : electromechanical coefficient). The ceramics exhibited microstructures with high density and low porosity and had a maximum relative density of 95.68 %. At x = 0.01, the ceramics exhibited a uniformly distributed small domain structures with nanodomains, accounting for their high-voltage electrical properties. Because these stable and reliable piezoelectric (1- x)KNLNS– x BNZT ceramics exhibit excellent electrical performance, they can replace lead–based materials. The direct solid–phase sintering method provides prospects for the large–scale application of the lead–free piezoelectric ceramics. The 0.99(K 0 · 48 Na 0 · 48 Li 0.04)(Nb 0 · 975 Sb 0.025)O 3 –0.01(Bi 0 · 5 Na 0.5)(Zr 0 · 8 Ti 0.2)O 3 ceramics exhibit excellent piezoelectric properties owing to their nanodomain structures, rhombohedral–tetragonal coexistence phase boundaries at room temperature (25°C ± 5°C) and dense microstructures. [Display omitted] [ABSTRACT FROM AUTHOR]

High entropy alloys (HEAs) are promising electromagnetic wave absorption (EMA) materials due to its designable crystal structure, variable electromagnetic properties, and excellent corrosion resistance. However, the impedance mismatch owing to the high electric and dielectric conductivity severely hinders the application of HEAs in the field of EMA. Herein, the lattice distortion of FeCoNiCu HEA is manipulated accurately by doping and annealing strategies to tailor the EMA properties. Significant lattice distortion is observed in the FeCoNiCuC0.37, which leads to a decrease in the electrical conductivity and the creation of abundant dipoles. Owing to the optimal impedance matching and boosted polarization loss, the FeCoNiCuC0.37 delivers a minimal reflection loss of −65.4 dB accompanied by an effective absorption bandwidth (EAB) of 6.81 GHz. After annealing at 200 °C, the EAB of the FeCoNiCuC0.37 is further increased to 7.99 GHz at 1.95 mm, which is better than that of most HEA‐based EMA absorbers reported so far. Moreover, it demonstrates excellent corrosion resistance owing to the more tortuous diffusion path of corrosive medium origin from lattice distortion. Thus, the study provides a new insight into designing high performance HEA‐based EMA materials with superior anti‐corrosion property by lattice distortion engineering. [ABSTRACT FROM AUTHOR]

Heterovalent ion doping has influenced the further development of piezoelectric applications. Pr3+ doping in relaxor ferroelectrics is rarely focused on piezoelectric performance enhancement. 0.51 Pb(Ni 1/3 Nb 2/3)O 3 -0.49 Pb(Hf 0.3 Ti 0.7)O 3 (PNN-49PHT) ceramics with Pr3+ doping ceramics were designed and fabricated by a two-step precursor method. Excellent dielectric diffusion coefficient (γ) of 1.96 was achieved at the low Pr3+ doping concentration of 0.2 %. Increased relaxation enhanced the nanoscale domains formation, resulting in a giant strain response (d* 33) of 1400 pm/V at 10 kV/cm, and a total strain (S tol) of 0.27 % at 20 kV/cm. Structural refinement unveiled that the high piezoelectricity originated from the mainly substitution of Pr3+ for Pb2+ at the A-site, inducing lattice distortion and phase transitions. Local domain switching and long-range ordered destruction were investigated by piezoresponse force microscopy (PFM) and Scanning Electron Microscopy (SEM). These findings contribute to the advancement of piezoelectric devices and provide valuable insights for the design and optimization of high-performance piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

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

Simultaneously enhancing the strength, plasticity, and toughness of metal materials has been a prominent research objective. In this study, the precipitation of nano-scale vanadium carbide particles at a lower tempering temperature is controlled to achieve three key benefits: reducing lattice distortion in bainitic ferrite, strengthening through precipitation, and enhancing the toughness of bainitic ferrite, while also maintaining the content and stability of retained austenite. The adopted procedure increases the comprehensive mechanical properties of steel by 17%. In particular, the room-temperature impact toughness is increased by 41%. This comprehensive microstructure optimization endows bainitic steel with an excellent combination of mechanical properties.

Titanium alloys are extensively utilized in the aerospace industry due to their exceptional strength and resistance to corrosion. However, litmited performance and high dispersion has always existed for the traditional manufacturing process. A novel Electroshock Treatment (EST) procedure proposed by author's team can synergistically improve the mechanical properties and its consistency of titanium alloys under limited temperature rise, but the relevant mechanism is not yet clear. In present work, the effects of various EST conditions on the mechanical characteristics were investigated by uniaxial tensile testing, and the effect mechanism was revealed using multi-scale microstructure characterization of titanium alloys, such as SEM, EBSD and TEM. The uniaxial tensile test results show that, compared with the sample without EST, the average elongation after fracture improved by 12.5%, the strength-plastic product improved by 16.1%, and the consistency of UTS and elongation after fracture improved by 63.4% and 57.1%, respectively, with a slight increase of tensile strength (30 MPa) after appropriate treatment (current density of 0.93 × 108A/m2, and pulse duration of 300 ms). The multi-scale microscopic characterization reveals a more uniform distribution of stress concentration in TC11 titanium alloy following the appropriate EST process. Besides, the entanglement of dislocations is reduced with some dislocations being annihilated. Especially, the remaining dislocations undergoing orderly rearrangement at grain boundaries after EST. The homogenization of local lattice distortion distribution and orderly rearrangement of dislocations at grain boundaries are the primary factors contributing to the comprehensive improvement in the mechanical properties and consistency of TC11 Titanium alloy.

The present work aims to create lattice distortion and optimize the surface oxygen vacancy (OV) concentration in a model spinel (Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)3O4 high-entropy oxide (HEO) through a heteroatom La3+ doping strategy. As demonstrated, La3+ with a large radius can be doped successfully into the spinel lattice of (Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)3O4, thereby not only causing lattice distortion to increase oxygen vacancies but also refining crystalline grains and improving the specific area. Compared with the (Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)3O4 anode, the (La0.01CoCrFeMnNi)3/5.01O4 anode with moderate doping exhibits excellent cycling performance (1228 mAh·g−1 after 400 cycles at 0.2 A·g−1) and yields an increase of 75% rate capability at 3 A·g−1 (420 mAh·g−1 at 3 A·g−1). The desirable kinetic transport of electrons and diffusion of Li+ within the moderately La3+-doped anode and the synergistic interfacial pseudocapacitive behavior satisfy the redox reaction at a high rate, thus increasing rate capability.

Medium entropy alloys (MEAs) have attracted significant interest due to their exceptional mechanical characteristics. This study employs molecular dynamics simulations to investigate the impact of transition metal (TM) elements doping on the mechanical properties of face-centered cubic (FCC) (CrFeNi)100−xTMx(TM=Cu,Mo,Nb,Tiandx=0,4) MEAs. We have doped 4% TM elements with pure CrFeNi MEA and analyze several mechanical characteristics such as lattice distortion, Yield strength, elastic constants and moduli, Vickers hardness, machinability index, and Kleinman parameters. The correlation between elastic moduli and doping implies a decrement in the stiffness of (CrFeNi)100−xTMx alloys. To confirm the ductility, a thorough assessment involving Poisson's ratio, Cauchy's pressure, and Pugh's ratio are conducted. According to the anisotropy factor analysis, the presence of doping increases anisotropy in (CrFeNi)100−xTMx MEAs. The findings of our work suggest that the improved mechanical properties can be beneficial in the development of MEAs suitable for diverse applications.

The unique coherency strain hardening mechanism and sluggish precipitation kinetics of γ″ phase have enabled Inconel 718 excellent elevated temperature serving performance and formability. However, the orienting character of γ″ phase determines its precipitation mutability and its morphology is susceptible to external stress and plastic deformation. Inconel 718 alloy is generally fabricated through plastic processing technologies like forging and rolling, where heterogeneous γ″ particles are commonly observed after aging. Therefore, it is vital to reveal the structural factor inducing the heterogeneous γ″ precipitation caused by deformation to lay fundamentals for particle configuration control. For this purpose, the present work aimed to define the heterogeneous γ″ configuration induced by prior deformation and explore the relevant structural mechanism. The γ″ particle morphologies in directly-aged cold-rolled Inconel 718 were characterized, prior rolling deformation resulted in heterogeneous γ″ precipitation during the aging process, which was defined as the inequivalence in their relative number fraction and particle size of perpendicular γ″-variants. Deformation led to the formation of β grains with lattice distortion in Inconel 718 alloy, which was the primary structural factor to induce the heterogeneous γ″ precipitation. These results explained that the FCC-γ lattice distortions caused by plastic deformation were responsible for the heterogeneous precipitation of second-particles.

Refractory high-entropy alloys (RHEAs) have remarkable properties like high strength and thermal stability at high temperatures. Their practical application is hindered by ambient brittleness and inferior formability. Titanium (Ti) is recognized as a crucial element in improving the ductility and oxidation resistance of RHEAs, but its plasticizing mechanism is still unclear. To address this, a series of body-centered cubic (BCC) single-phase VNbTaTix alloys were designed. The alloys exhibited exceptional ductility and cold-rolling formability at room temperature. Remarkably, the tensile fracture elongation of VNbTaTi alloy was about 26.9%, which surpassed most RHEAs. The major plastic mechanisms of the alloys are a/2-type dislocation and {1 1 2}-type twinning. Solid solution strengthening was identified as the primary strengthening mechanism. Although Ti reduced the solid solution strengthening effect, it contributed to weight reduction and enhanced local lattice distortion. This study not only designed several RHEAs with ductility but also provided insights into the effect of Ti content on their phase stability, lattice distortion, and strength mechanisms. These findings have significant implications for designing new RHEAs with ambient ductility.

BaTiO3, as a perovskite type material with excellent chemical stability and suitable conduction, has been widely studied in the field of photocatalysis. However, it can only absorb ultraviolet light because of its wide band gap. Herein, the lifetime of photogenerated electrons of BaTiO3 doped with Ta5+ can be enhanced. To study the band structure and photocatalytic performance of Ta‐doped BaTiO3, sol‐gel assisted solid‐phase method was employed to prepare BaTiO3 doped with varying Ta5+ doping amounts, and the structure characteristic and formation mechanism of the Ta‐doped BaTiO3 were analyzed. The results showed that the heat treatment temperature reached 1052.7 °C, sufficient thermodynamic conditions were obtained for Ta5+ to dope into the BaTiO3 lattice, and lattice distortion occurred in BaTiO3. Meanwhile, the particle size after doping decreased with the increase of Ta5+ doping amount. The 1.25 mol %Ta5+‐doped BaTiO3 had the lowest band gap (3.077 eV), and the photocatalytic water splitting had the best hydrogen evolution activity, which was 2.4 times that of BaTiO3. Furthermore, the conductance potential of 1.25 mol %Ta5+‐doped BaTiO3 was more negative than that of BaTiO3, which improved the thermodynamic advantage of the photocatalytic water splitting, and it had higher and more stable photoresponse and photogenerated carrier migration rate. [ABSTRACT FROM AUTHOR]

High entropy thermoelectric oxides offer a route towards highly efficient thermoelectric energy conversion as the materials frustrate parasitic phonon transport. Here, entropy-stabilised perovskite oxide thermoelectrics (Ca 0.33 Sr 0.33 Ba 0.33)(Ti 0.5−x Zr 0.5−x Nb x)O 3 (x = 0, 0.1, 0.2, 0.33) were prepared via solid-state reaction with sintering at 1673 K under a reducing atmosphere. The products contained two high entropy perovskite phases with homogeneous elemental distributions at the nanoscale. Through optimising the Nb content, the Seebeck coefficient was increased, yielding an enhanced power factor of 39.5 μW m−1 K−2 at 873 K. High resolution transmission electron microscopy revealed the presence of a large number of defects of different dimensionality, which enhanced phonon scattering. A glass-like, ultra-low thermal conductivity of 1.6 – 1.9 W m−1 K−1 was achieved from room temperature to 873 K, amongst the lowest reported values for perovskite oxides. This work highlights the design of high entropy oxide perovskites based on non-toxic components having both high Seebeck coefficients and ultra-low thermal conductivity. [ABSTRACT FROM AUTHOR]

In the thermal protection system of spacecraft, the bolts connecting the ceramic to the internal superalloy need to have low thermal conductivity and high strength. Two dense high entropy fluorite oxides (Zr 1/7 Hf 1/7 Ce 1/7 Y 2/7 La 2/7)O 2-δ (ZHCYL) and (Zr 1/8 Hf 1/8 Ce 1/8 Y 1/4 La 1/4 Pr 1/8)O 2-δ (ZHCYLP) were designed and synthesized by using the synergistic effect of plasma-assisted ball milling and spark plasma sintering(SPS). Through the synergistic effect of lattice distortion and oxygen vacancy guided by entropy regulation, ZHCYLP synthesized in this study has lower thermal conductivity(1.13 W·m−1·K−1), higher high temperature strength(192 MPa at 1000 °C) and high temperature phase stability up to 1600 °C than 8YSZ ceramics. The thermo-mechanical coupling finite element analysis results of high temperature bending test show that the variation trend of the maximum stress value of the sample is consistent with the experimental results. This shows that the mechanical and thermal properties of high entropy oxides can predict the variation trend of the maximum stress value in high temperature bending tests. It opens up a new way for designing and synthesizing high entropy oxide materials with low thermal conductivity and high strength which can be applied in the field of heat protection and load bearing. [ABSTRACT FROM AUTHOR]

The bulk Na5Lu9F32 single crystals with high quality serial Eu3+/Gd3+ co‐doped were grown by an ameliorative Bridgman technique. The measurement of X‐ray diffraction (XRD) and analysis of Rietveld refinement were implemented to validate the crystal phase. The Eu3+ doped Na5Lu9F32 single crystal emits intense red emission at 611 nm excited by 394 nm light. The intensity of 1.8 mol % Gd3+ doped sample is boosted by 3.56 times compared with the un‐doped one. The doping of Gd3+ ions replace competitively Lu3+ lattice sites with Eu3+ ions. Thus, they cause the lattice distortion and reduction of symmetry, enabling Eu3+ ions to overcome their 4f forbidden transitions. The change of Eu3+ ion local environment induced by Gd3+ ion doping was explored by the Eu3+ emission spectra and the variations of ratios between red and orange emission intensities (R/O). The fluorescence lifetime indicates that the introduction of GdF3 decreases the probability of non‐radiative transitions and increases the fluorescence lifetime. These results demonstrated that the Na5Lu9F32: Eu3+ single crystal doped with an appropriate concentration of GdF3 is a type of promising red emission single crystal for related optical devices of detector and laser due to its strong red emission, high transparency and high physico‐chemical stability. [ABSTRACT FROM AUTHOR]

Broadband absorber materials with high solar absorptivity and infrared emissivity are conducive to high-efficient and cost-effective heating technology in the civil and industrial field. The BaTi 1- x Co x O 3 ceramics are prepared by sol-gel method, showing mixed tetragonal/hexagonal phases. Co doping slightly reduces the phase transition temperature of BaTiO 3. Meanwhile, BaTi 1- x Co x O 3 ceramics present a composite Mott/charge transform band nature and the Co-3d impurity level and oxygen vacancies level lead to a narrowed bandgap. The enhancement of the absorption induced by free carriers, impurity level and lattice vibration promote the UV-Vis-NIR absorption and mid-infrared radiation of BaTi 1- x Co x O 3 ceramics. In conclusion, the optimized BaTi 0.95 Co 0.05 O 3 ceramic achieves a high solar absorptivity (0.88) in 0.25–2.5 µm and a high infrared emissivity (0.83) in 8–14 µm. The radiative performance presents good temperature stability, unaffected by phase structure and lattice thermal expansion, which provides prospective applications in solar energy conversion and infrared radiation heating. [ABSTRACT FROM AUTHOR]

The bulk Na5Lu9F32 single crystals with high quality serial Eu3+/Gd3+ co‐doped were grown by an ameliorative Bridgman technique. The measurement of X‐ray diffraction (XRD) and analysis of Rietveld refinement were implemented to validate the crystal phase. The Eu3+ doped Na5Lu9F32 single crystal emits intense red emission at 611 nm excited by 394 nm light. The intensity of 1.8 mol % Gd3+ doped sample is boosted by 3.56 times compared with the un‐doped one. The doping of Gd3+ ions replace competitively Lu3+ lattice sites with Eu3+ ions. Thus, they cause the lattice distortion and reduction of symmetry, enabling Eu3+ ions to overcome their 4f forbidden transitions. The change of Eu3+ ion local environment induced by Gd3+ ion doping was explored by the Eu3+ emission spectra and the variations of ratios between red and orange emission intensities (R/O). The fluorescence lifetime indicates that the introduction of GdF3 decreases the probability of non‐radiative transitions and increases the fluorescence lifetime. These results demonstrated that the Na5Lu9F32: Eu3+ single crystal doped with an appropriate concentration of GdF3 is a type of promising red emission single crystal for related optical devices of detector and laser due to its strong red emission, high transparency and high physico‐chemical stability. [ABSTRACT FROM AUTHOR]

Bismuth titanate (BIT) is widely known as one of the most prospective lead‐free ferroelectric and piezoelectric materials in advanced high‐temperature sensing applications. Despite significant advances in developing BIT ferroelectrics, it still faces major scientific and engineering challenges in realizing super‐high performance to meet next‐generation high‐sensitivity and light‐weight applications. Here, a novel ferroelectric domain‐engineered BIT ceramic system is conceived that exhibits super‐high piezoelectric coefficient (d33 = 38.5 pC N−1) and inverse piezoelectric coefficient (d33* = 46.7 pm V−1) at low electric field as well as excellent fatigue resistance (stable up to 107 cycles). The results reveal that the introduction of high‐density layered (001)‐type 180° domain walls with flexible polarization rotation features and the formation of small‐size multi‐domain states with low energy barriers are mainly responsible for the excellent electrical performance. To the best of knowledge, it is the first time to reveal such intriguing domain structures in BIT ceramics in detail, especially from the atomic‐scale perspective by using atomic number (Z)‐contrast imaging in combination with atomic‐resolution polarization mapping. It is believed that this breakthrough conduces to comprehensively understand structural features of ferroelectric domains in BIT ceramics, and also opens a window for future developments of super‐high performance in bismuth layer‐structured ferroelectrics via domain engineering. [ABSTRACT FROM AUTHOR]

A series of high entropy niobates with cation at A-site varying in size disorder and mass disorder is designed. High entropy niobates are all monoclinic structures with uniform rare-earth element distribution, but different space groups, which are closely related to the average radius at A-site. High entropy niobates possess excellent sintering resistance and ultra-low thermal conductivity due to stronger phonon-point defect scattering and shorter phonon lifetime. The effect of high entropy on average grain size and thermal conductivity is inversely proportional to size disorder. Moreover, the radiative heat transfer of (Dy 0.2 Ho 0.2 Er 0.2 Y 0.2 Yb 0.2)NbO 4 is substantially reduced due to the co-doping of active multi-component Dy3+, Er3+, and Yb3+, which broadens the range of intrinsic absorption band and improves lattice absorption derived from lattice distortion. Besides, the (La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Y 0.2)NbO 4 exhibits an ultra-high thermal expansion coefficient (12.34 ×10−6 K−1, 673 °C). The excellent thermophysical properties imply that high entropy niobates are more promising thermal barrier coating materials. [ABSTRACT FROM AUTHOR]

Near‐infrared (NIR) phosphors have been widely used in biomedical applications based on their deep tissue penetration. However, the lack of blue‐pumped NIR phosphors with emission ranges beyond 1000 nm has greatly limited the development of NIR phosphor‐converted light‐emitting diodes (pc‐LEDs). Herein, a facile way to boost the luminescence efficiency and thermal stability by introducing the promoters of Ce3+ and Na+ into Nd3+‐doped SrS NIR phosphor is demonstrated, thus achieving light emitting at 850–1500 nm with a peak wavelength of ≈1070 nm. Through sensitization by the allowed 4f → 5d transition of Ce3+, the SrS: Nd3+ phosphors are excitable by using a commercial blue LED, attributing to the effective energy transfer between Nd3+ and Ce3+. Besides, the structural analysis and density functional theory calculations reveal the lattice distortion mechanism and geometry of doping ions contributed to the weakened thermal quenching effect and the increasing of internal quantum efficiency. The optimized NIR phosphor luminescence intensity remains at 91.8% of the initial intensity at 393 K, and the internal quantum efficiency increases to 42.8% from 31.7% of the sample without Na+ doping. The present exploration of Nd3+‐doped NIR phosphors will provide a reference for designing NIR pc‐LEDs with enhanced properties.

Highlights A percolating network of distorted 2D Pt nanomembranes was synthesized by polymer surface buckling-enabled exfoliation for hydrogen evolution reaction. The 2D Pt nanomembrane enabled important technological applications for its high efficiency, low costs, and good stability, making it potential alternative to commercial Pt/C. Our 2D Pt nanomembranes offer insights into a new mechanism for efficient catalyst design strategy: lattice distortion-induced heterogeneous strain.

The rapidly advancing energy storage performance of dielectric ceramics capacitors have garnered significant interest for applications in fast charge/discharge and high-power electronic techniques. Simultaneously improving the recoverable energy storage density Wrec and efficiency η becomes more prominent at the present time for their practical applications. Herein, a high-entropy concept is implemented on the (K0·5Na0.5)NbO3 (KNN)-based ferroelectric ceramics to design the high-performance dielectric capacitors. First, the strong lattice distortion can absorb some electric energy during the electrical loading process and result in the delayed polarization saturation. Additionally, the large composition fluctuations induce the weak correlation between polar nanoregions and enhance the η. Finally, the high-entropy design and viscous polymer processing method reduce the grain size and improve the Eb. In consequence, excellent Wrec of 11.14 J/cm3 with high η of 87.1% are achieved under an electric field of 750 kV/cm in the high-entropy component. These results demonstrate that the high-entropy concept is a potential avenue to design the KNN-based high-performance dielectric energy storage capacitors.

ZrO 2 :(0.01)Dy3+:xA+ (A = Li+, Na+ and K+) phosphors were prepared by one step solution combustion method. X-ray diffraction (XRD), reveal formation of different phases. Functional group presence and its vibrations are assigned from FTIR measurements. Influence of alkali metal ions (A+) on surface morphology were realized from SEM micrograph. XPS study was carried out to confirm the presence of Li+ ions. Photoluminescence (PL) spectra of the samples excited at 350 nm exhibited two strong emission peaks at 480 nm and 580 nm, which are characteristic transitions of Dy3+ ions. However, the relative intensity between these peaks varies considerably due to the variation of the co-dopant/compensator (Li+, Na+, K+) concentration, representing the variation of the crystal field. Effects of different charge compensators (A+) and their concentration on the structural and luminescence properties of ZrO 2 :(0.01)Dy3+:xA+ phosphors were thoroughly investigated. Further, Judd-Ofelt parameters were calculated. Total emission colour (TEC) concentration of ZrO 2 :(0.01)Dy3+ phosphors were improved remarkably with the addition of charge compensators (A+), which would promote their applications in solid state lighting. The effective blue emission of the phosphors was changing with different co-dopant incorporation. Implying possible use of this material as a blue emitting phosphor as a blue emitting component in three-component white light-emitting diodes (WLEDs). [ABSTRACT FROM AUTHOR]

Ionic crystal ceramics are known to be susceptible to brittle cracks along the intergranular due to the strong ionic bond forces. Accordingly, an outstanding toughened coating consisting of yttria-stabilized tetragonal zirconia (YSTZ) and MgO, with a reinforced heterointerface, has been successfully achieved through the plasma electrolytic oxidation process. The results demonstrate that the enhanced Zr/Y–O bond strength improves the interfacial strength of the ionic crystal, while the lattice distortion activates continuous dislocation pinning at the (101) YSTZ//(111) MgO semicoherent heterointerface effectively hinders crack propagation of the coating. With the YSTZ content approaching 65 %, the toughness (K IC) value surpasses that of PEO coating by 42 %. These findings not only elucidate the scientific foundation for the improved toughness of the YSTZ/MgO nanocoating but also provide valuable insights into design strategies for improving ceramic toughness. [ABSTRACT FROM AUTHOR]

Electric field (E) control of magnetism is a persistent challenge in low-power consumption spintronic devices. A promising way to realize this control is to use the conversemagnetoelectric (ME) effect in insulating multiferroics.Here,we report considerable and repeatable E-modulated magnetization (M) at room temperature and even at 350 K via the significantly enhanced converseME effect near the morphotropic phase boundary (MPB) of the Cr-Mn co-doped (1-y)BiFe1-xCrxO3- yBaTi1-xMnxO3 (0.15 ≤ y ≤ 0.33, 0 ≤ x ≤ 0.03) solid solutions. In situ X-ray diffraction and Raman scattering experiments at different applied E for the sample near the MPB (i.e., y = 0.27, x = 0.03) show E-induced shift, broadening, and splitting in the {002}PC reflection, as well as a nearly monotonous variation in intensity of several phonon modes with E, reminiscent of the E-dependent M behavior. These results indicate that both E-induced lattice distortion and phase transformation dominate the converseME effects in these samples. Our demonstration of the E-regulation of magnetism via the E-sensitive crystal structures in designed insulating multiferroics near MPB may suggest a potential route to obtain efficient low-power spintronic devices. [ABSTRACT FROM AUTHOR]

High-performance lead-free piezoelectric thin films are urgently required for microelectromechanical systems. In this study, thin films based on the 0.8Bi0.5Na0.5TiO3-0.2(Sr0.7Bi0.20.1)TiO3 system were prepared on Pt(111)/TiOx/SiO2/Si substrates by a sol--gel method. The large lattice distortions were induced by introducing five rare-earth ions with different ionic radii (Er/Pr/Sm/Nd/La) to achieve the purpose of regulating the piezoelectric response of the thin films with the maximum inverse piezoelectric coefficient up to 425.9 pm/V. X-ray diffraction, Raman spectroscopy, Piezoresponse force microscope, and additional testing methods were used to observe the phase composition and microstructure of the thin films to investigate the effect of doping rare-earth elements with different ionic radii at the A-site on lattice distortion, and to summarize the transformation law. This study is significant for improving the piezoelectric properties of thin films and has crucial applications in microelectronic sensing. [ABSTRACT FROM AUTHOR]

Large-grain UO 2 has attracted much attention due to its advantage of suppressing fission gas release by reducing the specific surface area of grain boundaries. In this study, a single grain growth additive MnO is selected to modify UO 2 by conventional pressureless sintering method. The effect of MnO modification on UO 2 densification and grain growth at temperatures between 1200 and 1700 °C was investigated in detail. 0.5 wt%MnO-UO 2 pellets can reach nearly 95% T.D. when sintered at 1200 °C for 24 h. An average grain size greater than 300 µm can be obtained at 1700 °C for 24 h. A series of sintering experiments were designed and conducted to verify the specific mechanism of MnO on the grain growth of UO 2. The classical grain growth kinetics indicates that the grain growth exponent of MnO modified UO 2 in the early stage is 3, which corresponds to the lattice diffusion under pore control, while that of UO 2 is 2 and conforms to the grain boundary migration control. The SEM results show that there is solute segregation of MnO at the grain boundaries, followed by nucleation of lamellar structure in the form of piles and plates on the boundaries after high temperature treatment and traces of liquid phase in some region. Diffusion sintering experiments show that the mechanism of MnO-promoted UO 2 grain boundary migration is based on solid phase diffusion. The XRD results of UO 2 modified with different amounts of MnO demonstrate that the growth degree of UO 2 grains can be related to the variation of lattice parameters resulted from the MnO modification. This is due to the enhanced mobility of UO 2 grain boundaries because of the large distortion of surrounding lattice caused by Mn modification. These results can provide new ideas for the manufacture of UO 2 ceramic fuels. [ABSTRACT FROM AUTHOR]

Here, a novel aluminum-gallium-phosphate (GAHPO) metal-inorganic framework structure was prepared by hydrothermal method, and it was fully characterized by single crystal X-ray diffraction, powder X-ray diffraction, IR spectroscopy, and gravimetric analysis-differential scanning calorimeter (TG-DSC). Single crystal X-ray diffraction results show that GAHPO is attributed to the trigonal system and Rc3 space group. Al(Ga) O6 octahedra and PO4 tetrahedral structures is distorted to form one-dimensional chains, and then is stacked into three-dimensional metal-inorganic frameworks through hydrogen bonding. TG-DSC shows that GAHPO is of high thermal stability, with the initial decomposition temperature of 240 ²C. Compared with aluminum phosphate, the introduction of Ga3+ distorted the AlPO4 lattice, thus weakening and elongating the Al--O bond, which makes more acid catalytic sites exposed and enhanced the catalytic activity. The experiment shows that when the reaction temperature is 60 ²C, and the catalyst dosage is 10% of acetaldehyde, GAHPO could catalyze the condensation of acetaldehyde to produce butanolal with good conversion rate (47%) and excellent selectivity ( >99%). The reaction mechanism of acetaldehyde condensation catalyzed by GAHPO was investigated using scavengers, NH3-TPD and specially designed derivatives to confirm the reactive sites of the catalyst and the substrate. This work provides a feasible way for novel aluminum inorganic framework structures and the catalytic applications. [ABSTRACT FROM AUTHOR]

CrAlN and CrAlBN coatings were prepared on the surface of high-speed steel and shaper cutter by physical vapor deposition (PVD) technique using arc ion source. In the process of coating preparation, the adhesive layers were deposited by low bias voltage (−40 V) and the working layers are deposited by high bias voltage (−130 V). The effects of the addition of B element on the microstructure, hardness, elastic modulus and wear resistance of CrAlBN coating were studied. The results show that B element and its compounds exist in amorphous form in the coating, resulting in lattice distortion of the coating, increase of coating hardness to 37.1 GPa, and decrease of elastic modulus to 406.2 GPa. The addition of B element increases the uniformity of the columnar structure distribution and decreases the width of the columnar structure and grain size. The resistance to elastic deformation and plastic deformation of CrAlBN coating is improved, the wear resistance is improved. The performance of CrAlN and CrAlBN coatings on shaper cutter was studied. It was found that the main failure mode of shaper cutters is boundary wear and the wear mechanism of coatings had changed obviously. CrAlBN coating is mainly due to fatigue induced failure, accompanied by some diffusion wear. The addition of B element makes the CrAlBN coating have excellent resistance to oxidative wear, abrasive wear and diffusion wear during cutting. The results show that the addition of B element can improve the microstructure and mechanical properties of CrAlN coating, and the preparation of CrAlBN coating on the surface of the shaper cutter can significantly improve the service life of the coated shaper cutter, which has significance for the development of the shaper cutter industry. [ABSTRACT FROM AUTHOR]

The production of formic acid via electrochemical CO2 reduction may serve as a key link for the carbon cycle in the formic acid economy, yet its practical feasibility is largely limited by the quantity and concentration of the product. Here we demonstrate continuous electrochemical CO2 reduction for formic acid production at 2 M at an industrial‐level current densities (i.e., 200 mA cm−2) for 300 h on membrane electrode assembly using scalable lattice‐distorted bismuth catalysts. The optimized catalysts also enable a Faradaic efficiency for formate of 94.2 % and a highest partial formate current density of 1.16 A cm−2, reaching a production rate of 21.7 mmol cm−2 h−1. To assess the practicality of this system, we perform a comprehensive techno‐economic analysis and life cycle assessment, showing that our approach can potentially substitute conventional methyl formate hydrolysis for industrial formic acid production. Furthermore, the resultant formic acid serves as direct fuel for air‐breathing formic acid fuel cells, boasting a power density of 55 mW cm−2 and an exceptional thermal efficiency of 20.1 %. [ABSTRACT FROM AUTHOR]

Wide‐bandgap (WBG) perovskite solar cells (PSCs) have been widely used as the top cell of tandem solar cells. However, photoinduced phase segregation and high open‐circuit voltage loss pose significant obstacles to the development of WBG PSCs. Here, a two‐step small‐size A‐site and large‐size X‐site incorporation strategy is reported to modulate the lattice distortion and improve the film quality of WBG formamidinium‐methylammonium (FAMA) perovskite films for photostable PSCs based on two‐step deposition method. First, CsI with content of 0–20% is introduced to tune the lattice distortion and film quality of FAMA perovskite with a bandgap of 1.70 eV. Then, 4% RbI is incorporated to further modulate the perovskite growth and lattice distortion, leading to the suppression of photoinduced phase segregation in the resultant RbCsFAMA quadruple cation perovskites. As a result, the 20%CsI/4%RbI‐doped device obtains a promising efficiency of 20.6%, and the corresponding perovskite film shows good photothermal stability. Even without encapsulation, the device can maintain 92% of its initial efficiency after 1000 h of continuous operation under 1 sun equivalent white light‐emitting diode illumination. [ABSTRACT FROM AUTHOR]

The commercialization of high‐performance nickel‐rich cathodes always awaits a cost‐effective, environmentally friendly, and large‐scale preparation method. Despite a grinding process normally adopted in the synthesis of the nickel‐rich cathodes, lattice distortion, rough surface, and sharp edge transformation inevitably occurr in the resultant samples. In this work, an additional annealing process is proposed that aims at regulating lattice distortion as well as achieving round and smoother morphologies without any structural or elemental modifications. Such a structural enhancement is favored for improved lithium diffusion and electrochemical stability during cycling. Consequently, the annealed cathodes demonstrate a considerable enhancement in capacity retention, escalating from 68.7% to 91.9% after 100 cycles at 1 C. Additionally, the specific capacity is significantly increased from 64 to 142 mAh g−1 at 5 C when compared to the unannealed cathodes. This work offers a straightforward and effective approach for reinforcing the electrochemical properties of nickel‐rich cathodes. [ABSTRACT FROM AUTHOR]

Charge density wave (CDW) is a phenomenon that occurs in materials, accompanied by changes in their intrinsic electronic properties. The study of CDW and its modulation in materials holds tremendous significance in materials research, as it provides a unique approach to controlling the electronic properties of materials. TiSe2 is a typical layered material with a CDW phase at low temperatures. Through V substitution for Ti in TiSe2, we tuned the carrier concentration in VxTi1−xSe2 to study how its electronic structures evolve. Angle-resolved photoemission spectroscopy (ARPES) shows that the band-folding effect is sustained with the doping level up to 10%, indicating the persistence of the CDW phase, even though the band structure is strikingly different from that of the parent compound TiSe2. Though CDW can induce the band fold effect with a driving force from the perspective of electronic systems, our studies suggest that this behavior could be maintained by lattice distortion of the CDW phase, even if band structures deviate from the electron-driven CDW scenario. Our work provides a constraint for understanding the CDW mechanism in TiSe2, and highlights the role of lattice distortion in the band-folding effect. [ABSTRACT FROM AUTHOR]

Lead-based piezoelectric ceramics are the preferred material for commercial piezoelectric ceramic actuators due to their high performance and irreplaceability. However, the operating temperature (<100 °C) and strain (0.1 %∼0.2 %) of lead-based piezoelectric ceramics are still limited. Achieving large strain in a wide temperature range remains challenging. In this paper, a new strategy is proposed to effectively increase the strain value of lead-based piezoelectric ceramics through domain engineering. The new x PbTiO 3 -(0.97- x)PbZrO 3 -0.03(La 0.1 Sr 0.80.1)TiO 2.95 (x PT-PZ-LST) ternary piezoelectric ceramic system reaches a strain value as high as 0.5 % and exhibits extremely high temperature stability (13 %) in the range of 25–230 °C. By fine-tuning the content of PT components, the average length and width of a typical tetragonal domain are transformed from 800 nm to 80 nm (long and thin) to 300 nm and 200 nm (short and wide), relatively. From the experimental results of PFM and Rayleigh analysis, the high strain can be attributed to the synergistic effect of the reduced coercive field (E c), enhanced micro-region response, and regulated domain morphology, which ensures that high intrinsic and extrinsic contribution can be achieved at the same time. In this paper, a new strain regulation method is provided for lead-based piezoelectric ceramics, and a valuable large strain material is obtained via domain engineering. [ABSTRACT FROM AUTHOR]

Highlights: A percolating network of distorted 2D Pt nanomembranes was synthesized by polymer surface buckling-enabled exfoliation for hydrogen evolution reaction. The 2D Pt nanomembrane enabled important technological applications for its high efficiency, low costs, and good stability, making it potential alternative to commercial Pt/C. Our 2D Pt nanomembranes offer insights into a new mechanism for efficient catalyst design strategy: lattice distortion-induced heterogeneous strain. Hydrogen production through hydrogen evolution reaction (HER) offers a promising solution to combat climate change by replacing fossil fuels with clean energy sources. However, the widespread adoption of efficient electrocatalysts, such as platinum (Pt), has been hindered by their high cost. In this study, we developed an easy-to-implement method to create ultrathin Pt nanomembranes, which catalyze HER at a cost significantly lower than commercial Pt/C and comparable to non-noble metal electrocatalysts. These Pt nanomembranes consist of highly distorted Pt nanocrystals and exhibit a heterogeneous elastic strain field, a characteristic rarely seen in conventional crystals. This unique feature results in significantly higher electrocatalytic efficiency than various forms of Pt electrocatalysts, including Pt/C, Pt foils, and numerous Pt single-atom or single-cluster catalysts. Our research offers a promising approach to develop highly efficient and cost-effective low-dimensional electrocatalysts for sustainable hydrogen production, potentially addressing the challenges posed by the climate crisis. [ABSTRACT FROM AUTHOR]

It is well demonstrated that the complex chemical fluctuations on high/medium-entropy alloys (H/MEAs) play critical roles in their deformation process, but there are few reports related to the effect of such complex chemical fluctuations on the crack behavior. In this paper, the effects of chemical short-range order (CSRO) and lattice distortion (LD) on the crack-tip behavior of CrCoNi MEAs under mode I loading at room temperature are investigated by carrying out molecular dynamics (MD) simulation, hybrid MD/Monte-Carlo (MC) simulation and the J-integral method. The results reveal that CSRO can improve the J-integral value without significant changes in the localized deformation zone size. On the contrary, LD can lower the J-integral value with an increase in the localized deformation zone size. The energetic analysis shows that CSRO improves the activation energy barrier of Shockley partial dislocation from the crack-tip while LD reduces the activation energy barrier. Our work is a step forward in understanding the effects of CSRO and LD on the crack-tip behavior and deformation mechanisms of CrCoNi MEAs. [ABSTRACT FROM AUTHOR]

High entropy alloys (HEAs) were first reported in the early 2000s. High mixing entropy of the HEAs makes it present good thermal stability. Meanwhile, the large lattice distortion in the HEAs leads to significant solution strengthening. Additionally, cluster structures are formed within grains due to the large negative enthalpy. Consequently, the movement of dislocation is effectively hindered, and the strength of the HEAs is remarkably improved. Given to these unique characteristics, the HEAs is expected to have excellent physical and chemical properties at low and high temperatures. As a result, the HEAs have become a hot area with lots of published research papers. Based on existing physical and mechanical properties of the HEAs with BCC and FCC structure, relation among electron concentration, lattice constant, atomic mismatch, mixing enthalpy, hardness, elasticity modulus and normalized hardness were analyzed to develop a formula calculating elasticity modulus and hardness of the HEAs. On this basis, the composition design method of the HEAs with BCC and FCC structures is established by considering density, ductility and working environment. Finally, it is pointed out that the persistent strength of HEAs, the uniformity of composition and properties of large-sized ingots, and the preparation of large-sized alloy ingots are key issues that need to be addressed in the engineering application of HEAs.

Thermal barrier coatings (TBCs) are critical for the reliability and lifespan of aircraft engine turbine blades. In this study, a novel quaternary rare-earth oxide (La 2 O 3 , Gd 2 O 3 , Yb 2 O 3 , and Y 2 O 3) co-doped ZrO 2 solid solution, referred to as 1La-xGd-2Yb-3.5YSZ, was synthesized by varying the doping amount of Gd 2 O 3 from 0 to 6 mol. %. The impact of co-doping-induced lattice distortion on the phase composition, high-temperature phase stability, sintering resistance, and mechanical and thermal properties of the solid solution has been explored. It is found that the addition of Gd 2 O 3 stabilizer effectively increased the lattice distortion of the solid solution, which led to improved phase stability and sintering resistance, enhanced mechanical properties, and low thermal conductivity. Our findings highlight the promising properties of the 1La-xGd-2Yb-3.5YSZ solid solution, making it an attractive candidate for TBC materials. [ABSTRACT FROM AUTHOR]

Owing to their adaptable topologies and simplicity of functionalization, metal–organic frameworks (MOFs) are highly sought-after materials for battery-type electrodes. To improve the MOFs' overall conductivity and instability, a Ni/Co-MOF nanostructure grows in situ on nickel foam (NF) with the controlled introduction of structural defects using a one-step solvothermal method. Benzoic acid (BA) is selected as the cost-effective regulator and ligand to compete with the original ligand terephthalic acid (TPA), for inducing lattice distortion. The incorporation of BA results in increased micropore volume and surface area. These characteristics improve the contact between the electrode and electrolyte, leading to a rapid redox reaction. Thus, the defective sample Ni/Co-MOF/NF with 10% BA exhibits an ultrahigh capacity of 352.3 mAh g–1 at a current density of 1 A g–1. Moreover, the assembled hybrid supercapacitor device (10% Ni/Co-MOF/NF//AC) demonstrates a suitable energy density of 33.5 Wh kg–1 at a power density of 404.6 W kg–1 and 90.3% capacitance retention after 8000 cycles. These findings provide valuable insights for developing ultrahigh-performance MOF nanostructures that can be directly used as supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

In this paper, CoMn based nanowires were in-situ grown on foam nickel by hydrothermal method combined with calcination treatment, and a monolithic methane oxidation catalyst was obtained. The effects of hydrothermal temperature and calcination temperature on the crystal structure, micro morphology and catalytic performance of the catalysts were systematically studied. The results indicated that when the hydrothermal temperature was 160 °C and the calcination temperature was 350 °C, Mn doped Co 3 O 4 nanowires with uniform morphology can be obtained, accompanied by the appearance of CoMn 2 O 4. The introduction of Mn ions caused lattice distortion of Co 3 O 4 , achieving the regulation of adsorbed oxygen and lattice oxygen. The monolithic MnCoO/NF–H-160 °C catalyst showed the best catalytic activity (T 90 = 414 °C) for lean methane catalytic oxidation, which even surpassed the noble metal based catalyst. Its excellent catalytic activity was due to the fact that the catalyst can expose more active sites, rich active oxygen and good mass transfer characteristics. This study provides a new approach for designing efficient monolithic catalysts and has significant potential for application and development in the field of organic waste gas treatment. [ABSTRACT FROM AUTHOR]

The new (0.96‐x)(K0.48Na0.52Nb0.96Sb0.04)O3‐0.04(Bi0.5Ag0.5)ZrO3‐x(Fe2O3‐In2O3) ceramics with high dielectric, and electromechanical coupling properties were designed. In this work, the effect of KNN‐based ceramics lattice distortion (c/a) and microstructure on the electrical properties was explored by varying the doping amount of Fe3+ and In3+. The problem of a large number of oxygen vacancies generated by the volatilization of K and Na can be well solved by introducing Fe3+ and In3+. The bulk density increases significantly and the maximum value is about 4.52 g/cm3.The sample with x = 0.003 has the smallest c/a, and exhibits the best piezoelectric and dielectric properties (d33 = 536 pC/N, εr = 3432 and kp = 55.8 %). Low doping concentration of Fe2O3 is considered a "soft" addition for KNN‐based piezoelectric ceramics. The study of this mechanism provides a new idea to regulate the electrical performance of KNN‐based ceramics. [ABSTRACT FROM AUTHOR]