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One of the primary hurdles in microdevice fabrication lies in ascertaining the most impactful tactics for adapting metal surfaces. Through a one-pot tackle and distinct mechanochemical reactions evoked by 15 min aqueous wet sand-milling (SM-15), we successfully grafted Mo-based metal–organic frameworks (Mo-MOFs) onto graphene oxides (GOs). Following this, a convenient and readily scalable methodology of electrophoretic deposition was implemented to create controllable thickness of SM-15 GOs@Mo-MOFs lubricating films, achieving considerable enhancements of 143% and 91% in hardness and Young's modulus, respectively, when compared to those of SM-15 Mo-MOFs. The successful synthesis of SM-15 GOs@Mo-MOFs was corroborated using strategies such as x-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. Analyses using the micro-tribotester indicated that the new film exhibited a lowest friction coefficient of roughly 0.5 when imposed with a load of 5 N and sliding speed of 8 mm/s. In addition, the optical profiler nano-indentation in situ scanning probe microscope revealed that SM-15 GOs@Mo-MOFs films had smaller and shallower scratches and grooves compared to SM-15 Mo-MOFs ones. The calculated results of key descriptors (EHOMO, ELUMO, ΔE, etc.) in density functional theory quantitatively disclosed the interaction mechanisms between GOs@Mo-MOFs molecules and microdevices. We first scrutinized the innate properties of molecule adsorption energy and frictional mechanical behaviors using synergetic cross-scale simulations, such as Monte Carlo and finite element methods. The expectation was that this process would motivate a valuable technique for shielding in the thriving micromanufacturing. [ABSTRACT FROM AUTHOR]

Due to their nanoscale features, nanometric multilayers can have a large variation in properties for varying bilayer heights. While the hardening at small feature sizes and the consequent softening at even smaller feature sizes have been observed for decades, the underlying mechanisms are still under debate. In this study, molecular dynamics uniaxial compression simulations are employed to study the mechanical properties of Al/Ni multilayers for bilayer heights h from 100 nm down to 5 nm. The effect of the microstructure on Young's modulus and the yield strength was investigated. Furthermore, the mechanical properties of equiatomic and equivolumetric multilayers were compared. A comparison with experimental results from the literature showed good agreement. Both the hardening at intermediate bilayer heights as well as the softening at very small bilayer heights were observed. The results are discussed in the context of possible hardening and softening mechanisms. While the Hall–Petch effect with a h − 1 / 2 scaling is not contradicted, it is shown that, although the underlying mechanisms are different, both the hardening as well as the softening are based on a general size effect with a scaling of ln (h) / h. [ABSTRACT FROM AUTHOR]

Motivated by the recent experimental synthesis of two-dimensional (2D) NbOI2 which possesses a moderate bandgap and outstanding absorption of sunlight, using the first-principles calculations, we conduct a thorough study of the geometric configuration, electronic structures, and photocatalytic properties for NbOX2 (X = Cl, Br, I) monolayers. These NbOX2 monolayers have been demonstrated to be dynamically, thermally, and mechanically stable. The significant anisotropic mechanical properties of NbOX2 monolayers are reflected by the calculated Young's modulus and Poisson's ratio. Our results indicate that these NbOX2 materials unfold semiconductor characters with indirect bandgaps of 1.886, 1.909, and 1.813 eV, respectively. Among these monolayers, it is found that the NbOBr2 system exhibits a favorable photocatalytic activity in an acidic condition (pH = 0), and the NbOI2 monolayer can act as a potential photocatalyst for spontaneous photocatalytic water splitting under a neutral environment (pH = 7). Furthermore, the response of bandgap and band edge positions of NbOX2 monolayers to the exerting in-plane strain (–6% to 6%) are investigated. These NbOX2 monolayers also show strong light absorption from the visible to ultraviolet region and anisotropic high carrier transport. Particularly, the high solar-to-hydrogen efficiency of the NbOCl2 (1% tensile strain), NbOBr2, and NbOI2 monolayers are predicted to be 14.11% (pH = 0), 16.34% (pH = 0), and 17.05% (pH = 7), respectively. Therefore, we expect the NbOX2 monolayers to be promising candidates for highly efficient photocatalytic water splitting. [ABSTRACT FROM AUTHOR]

Due to high ion conductivity, low cost, and adjustable composition, antiperovskite has attracted much attention as a potentially useful material in solid-state batteries. Compared with simple antiperovskite, Ruddlesden–Popper (R–P) antiperovskite is an updated material, which is not only more stable but also reported to significantly enhance conductivity when added to simple antiperovskite. However, systematic theoretical research on R–P antiperovskite is scarce, hindering its further development. In this study, the recently reported easily synthesized R–P antiperovskite LiBr(Li2OHBr)2 is calculated for the first time. Comparative calculations were conducted on the transport performance, thermodynamic properties, and mechanical properties of H-rich LiBr(Li2OHBr)2 and H-free LiBr(Li3OBr)2. Our results indicate that due to the presence of protons, LiBr(Li2OHBr)2 is more prone to defects, and synthesizing more LiBr Schottky defects can improve its Li-ion conductivity. Young's modulus of the LiBr(Li2OHBr)2 is as low as 30.61 GPa, which is beneficial for its application as a sintering aid. However, the calculated Pugh's ratio (B/G) of 1.28 and 1.50, respectively, indicates that R–P antiperovskites LiBr(Li2OHBr)2 and LiBr(Li3OBr)2 exhibit mechanical brittleness, which is not conducive to its application as solid electrolytes. Through quasi-harmonic approximation, we found that the linear thermal expansion coefficient of LiBr(Li2OHBr)2 is 2.07 × 10−5 K−1, which is more advantageous in matching electrodes than LiBr(Li3OBr)2 and even simple antiperovskites. Overall, our research provides comprehensive insights into the practical application of R–P antiperovskite in solid-state batteries. [ABSTRACT FROM AUTHOR]

The research presented in the paper concerns the elastic properties of struvite. The article combines theoretical and experimental research. Experimental studies were carried out on struvite single crystals grown in sodium metasilicate gel by single diffusion. This unique method leads to obtaining crystals of sufficiently large size to conduct, for the first time, experimental measurement of elastic properties of monocrystalline struvite. Using the nanoindentation method, the Ez = 29.1 ± 0.7 GPa value of the component of Young's modulus was determined for a struvite single crystal. In addition, the elastic constants C11, C22, and C33 were determined using micro-Brillouin spectroscopy. Theoretical calculations of the abovementioned properties have been carried out by employing density functional theory methods. Scaling of the theoretical elastic constants leads to obtaining good agreement with the experimental values. Values of the Ex and Ey components of the Young's modulus, not available from the experimental nanoindentation technique, have been determined theoretically as 23 GPa and 27 GPa, respectively. Differences in the values of elastic components and Young's modulus components are related to the layered crystal structure of struvite and directional character of the hydrogen-bonding pattern. [ABSTRACT FROM AUTHOR]

Gravimeters fabricated with MEMS suffer from temperature-dependent drifts in their long-term stability. We analyze the thermal contributions to the signal, and we propose three mechanisms to mitigate their effects. The first one uses materials that fulfill the condition α E = − 2 α , where thermal expansion is canceled by the temperature variation of Young's modulus. The second one uses the thermal expansion to introduce a compression that compensates variation in the force of the spring. In the third one, expansion compensates the displacement of the proof mass in the sensor, rather than the force. The three mechanisms are robust since they only depend on the temperature of the sensor itself. [ABSTRACT FROM AUTHOR]

For better understanding the water influence on shale mechanical characteristics, chip, column, powder and semi-circular bend four types of shale sample from Longmaxi outcrop processed to 5 different moisture degree, are prepared to separately conduct SEM observation for in-situ location after processing, AFM test and nanoindentation for data of fracture toughness calculation, uniaxial/triaxial compression test for internal friction angle, nitrogen adsorption test for pore volume, SCB test for macro fracture toughness. An improved Energy-based method is proposed to calculate micro fracture toughness based on results from AFM test, in comparison with micro fracture toughness calculated with energy method and nanoindentation curves, the results of improved energy-based method are acceptable. By analogy with elastic modulus, a new method is proposed to calculate macro fracture toughness changing ratio with rising saturation based on micro fracture toughness computed with AFM test data including maximum force, maximum depth, contact area, hardness and elastic modulus. This method can be applied to computing macro brittleness changing ratio based on micro brittleness calculated with AFM test data, its changing pattern fits the pattern of brittleness computed by internal friction angle. Unlike fracture toughness getting down consistently, shale brittleness gets down initially then climbs up with rising saturation. But average value cannot represent macro level, the linear relationship between fracture toughness and Young's modulus disappears due to moisture influence. A comparative analysis between nanoindentation and AFM is conducted from three aspects, AFM is a better method to detect micro mechanical properties influenced by some factor at different degree.

This paper discusses a composite material from chopped thin narrow polymer tapes reinforced with carbon fibers and a polymer binder. The problem is posed to analytically determine the elastic and strength characteristics of the composite with a known minimum set of basic characteristics of the components. A methodology for sequential solving of the problem at the micro- and meso-levels is proposed. The key point in the methodology is the introduction of the “effective fiber volume factor” in the short filament and the way to calculate it using the “load-carrying factor” criterion. The following are presented: the results of calculating Young’s modulus and tensile strength of material samples from parts of tapes with fixed lengths (6, 12, 18 and 24 mm); comparison with the experimental data and evaluation of accuracy and limits of the applicability of this methodology.

Abstract Understanding the mechanical properties and porosity of reproductive tissues is vital for regenerative medicine and tissue engineering. This study investigated the changes in Young's modulus (YM), storage modulus (E′), loss modulus (Eʺ), and porosity of native and decellularized bovine reproductive tissues during the estrous cycle. Testis tunica albuginea had significantly higher YM, E′, and Eʺ than the inner testis, indicating greater stiffness and viscoelasticity. Endometrium showed no distinct differences in YM, E′, or Eʺ across the estrous cycle or between horns. Ovaries exhibited significant variations in YM, E′, Eʺ, and porosity, with higher YM and E′ in the ipsilateral cortex and medulla during the luteal phase. Decellularized ovarian tissues displayed increased porosity. The oviduct displayed no significant differences in YM or E′ in the isthmus, but the contralateral ampulla had reduced YM and E′ in the luteal phase. These findings offer valuable insights into the dynamic mechanical properties and porosity of reproductive tissues, facilitating the development of biomimetic scaffolds for tissue engineering applications.

It is well known that common orthopedic implant titanium materials have a higher Young's modulus (100+GPa) than bone. Stress shielding leaves the neighboring bone unstressed for long periods of time and bone resorption occurs around the implant, which triggers implant failure. Here, we developed a novel Ti–Mo–Zr alloy with a customizable Young's modulus by using in situ alloying and laser additive manufacturing (AM) methods. Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) were used to elucidate the distribution of submicron Mo particles in the materials, and selected laser melting (SLM) was used to customize the spatial concentration of Mo elements in novel alloys in a predictable way. By regulating the concentration and distribution of unmelted Mo particles, it is possible to tailor the grain growth angle and phases of the alloy. This results in excellent comprehensive mechanical properties for the alloys with a customizable Young's modulus ranging from 59.3 to 83.6 GPa, tensile strength from 564 to 1045 MPa, and a fracture strain of up to 13.1%. Orthopedic implants with a customizable Young's modulus can be adapted to bone tissues in different body parts, providing endless possibilities for personalized surgical solutions for patients. The economic potential for such materials in smart medical is enormous.

For decades, it has been widely accepted that adding Mg to Al alloys decays Young's modulus of Al alloys. However, the fundamental mechanism for Young's modulus reduction is still pending. In this study, we experimentally produce the Al–Li alloys and Al–Li–Mg alloys using centrifugal casting and trace Young's modulus as a function of the evolution of their precipitation structures. Atomic-resolution high-angle-annular-dark-field (HAADF) imaging in scanning transmission electron microscopy (STEM) indicates that the precipitate sizes of Al–Li and Al–Li–Mg alloys are essentially the same in the early and late stages of aging. While atomic resolution HAADF suggests that although the lattice constants of δ′-Al3Li in Al–Li and Al–Li–Mg alloys (0.404 nm) are consistent in the early aging stage, it changes to 0.422 nm in the Al–Li–Mg alloy at the end of peak aging, showing a significant expansion to the same level as α-Al (0.421 nm). The nanoindentation results confirm that Young's modulus decreases strongly from 89.04 to 76.39 GPa for Al–Li–Mg alloys due to the lattice relaxation. Combining atomic-resolution HAADF and first-principles calculations, it has been found that Mg atoms diffuse into Al3(Li, Mg) crystals by replacing Li in the L12 δ′-Al3Li and thus doping the crystal. Further, it has been found that Mg atoms expand the spacing between Al–Al and Al–Li pairs thereby lowering the energy between Al–Al and Al–Li bonds, which in turn stretches their potential energy curves reducing Young's modulus.

Silicone hydrogels coated with metallic nanostructures have attracted extensive attention because of their versatile applications in biomedical devices. However, few studies have been reported for characterizing the mechanical behavior of silicone hydrogel under biaxial tensile stresses. In addition, compared to most chemical coating processes, the deposition of nanostructures on silicone hydrogel by using a laser-assisted process can avoid chemical impurities and additional sterilization processes. Herein, a laser-assisted process is used for producing polyvinylpyrrolidone (PVP) modified silver (Ag) nanoparticles (Ag-PVP NPs), which are further deposited on silicone hydrogel. In the uniaxial mechanical test, the value of Young's modulus of Ag-PVP NP coated silicone hydrogels is increased as compared to that of silicone hydrogel. The energy absorption of silicone hydrogel and Ag-PVP NP coated silicone hydrogel measured by the uniaxial mechanical test is 15.137 ± 0.412 and 22.014 ± 0.186 MJ/m3, respectively. Furthermore, the biaxial test is applied to study the mechanical properties of silicone hydrogel coated with Ag-PVP NPs. Meanwhile, a constitutive model was applied to further understand the mechanical behavior of silicone hydrogel coated with Ag-PVP NPs. The result indicates that silicone hydrogel coated with Ag-PVP NPs shows a pseudo-elastic nonlinear behavior which is similar to collagen-based tissue substitutes. [ABSTRACT FROM AUTHOR]

The structural, mechanical, and electronic properties of Ni–Co-based layered transition oxide LiNixCo1−xO2 (x = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9) (LNCO) have been investigated using the first-principles method. The results show that the effect of Ni/Co mixing on the structural property is slight. For the case of the mechanical property, the elastic constant, elastic modulus, such as Young's modulus (Y), Poisson's ratio (v), Pugh's ratio (B/G), and Cauchy pressure (C′) of LNCO have been carefully analyzed based on the strain-energy method. The results demonstrate that the mechanical strength of LNCO materials is weaker than that of pure LiCoO2 (LCO) and LiNiO2 (LNO). However, the B/G ratio and Poisson's ratio of LNCO are greater than that of the pure LCO and LNO, which means that Ni/Co mixing can improve the ductility of pure LCO and LNO. In addition, Cauchy pressure and anisotropy are also discussed, and as cathode materials, LNCO still exhibits good electrical conductivity. Our results provide a feasible way to realize mechanical property modulation by Ni–Co-based layered transition metal oxides LCO. Furthermore, our study is also helpful to reveal the formation mechanism of intra-lattice microcracks in electrode materials. [ABSTRACT FROM AUTHOR]

The trade-off of stiffness and ductility of metals has long plagued materials scientists. To address this issue, atomic structure designs of short-range ordering (SRO) to sub-nanometer and nanometer scales have received much interest in tailoring the atomic environment and electronic interaction between solute and solvent atoms. Taking an example of Al–Li alloy with high specific stiffness and reverse correlation of Young's modulus and melting point, in this work, we investigate the SRO-dependent stiffness and intrinsic ductile–brittle properties by performing a full-configuration strategy containing various structural ordering features. It suggests that the short-range ordered arrangement of Li atoms can effectively enhance the stiffness while keeping ductility, playing a hydrostatic pressure-like role. Our findings present fundamental knowledge to enable high stiffness and ductility for solvent phases with low modulus through designing local short-range ordered cluster structures. [ABSTRACT FROM AUTHOR]

Nanostructures with high surface area to volume ratio, such as oxidized and coated Cu nanowires (NWs), exhibit unique mechanical properties due to their size and surface effects. Understanding the complex oxidation process of Cu NWs at nanoscale and quantifying its resulting effects on mechanical behavior and properties are significantly essential for effective usage of Cu NW devices in a wide range of applications in nanoelectronics. Here, we perform molecular dynamics simulations using ReaxFF (reactive force field) to investigate the oxidation process and mechanisms of [001]-oriented cylindrical Cu NWs and its contribution on the mechanical deformation behavior and material properties as a function of NW sizes. The relatively thin oxide CuxOy layer is formed on the surface of Cu NWs in an O2 environment, creating a core/shell (Cu/CuxOy) NW structure that played a key role in governing the overall tensile mechanical deformation behavior and properties of Cu NW. The formation of oxide layer effects, including the resulting interface and defects, leads to a reduction in the initial dislocation nucleation barrier, which facilitates the onset of plasticity and stress relaxation, ultimately resulting in a negative impact on the tensile strength, Young's modulus, yield stress and strain, and flow stress when compared to pristine counterparts. It is worth noting that the tensile mechanical response and properties of the Cu NWs are highly dependent on the pre-existing oxide shell layer associated with the size of NW, determining the overall mechanical performance and properties of Cu NWs. [ABSTRACT FROM AUTHOR]

The excellent shape stability of thermally expanded metamaterials and the good bandgap properties of acoustic metamaterials have a wide range of promising applications in aerospace and sensors. Here, a bi-material-directional honeycomb metamaterial (BHM) with tunable coefficient of thermal expansion (CTE) and bandgap properties is proposed. The theoretical analysis and numerical simulations are employed to reveal the thermal deformation mechanism of the BHM. In addition, the analytical expression of the effective Young's modulus is established by considering both tensile and bending deformation. Based on the Bloch theorem, the band structures of the BHM are calculated by the finite element method. Parameter analysis confirms that the CTE and bandgap of the BHM can be simultaneously regulated and drastically adjusted by changing the geometric parameters and material combinations. Meanwhile, the coupling relationship of the effective CTE, Young's modulus, and total effective bandgap width are investigated. The results show that the BHM can have tunable CTE function and large total effective bandgap width by selecting suitable parameters while satisfying stiffness requirements. This study achieves a dual objective of specific CTE properties and bandgap design through rational material selection and shape design, which makes the metamaterials have better tunability and multifunctionality. [ABSTRACT FROM AUTHOR]

We report here the FTIR, optical, and magnetic properties of Sn 1-x-y Zn x M y O z ceramics with various x, y, and M. The pure samples are called S1, S2, and S3 for ZnO, SnO 2 , and SnZn. The co-substituted samples are called S4, S5, S6, and S7 for SnZnFe, SnZnCo, SnZnNi, and SnZnMn, with Zn = 0.50, Sn = 0.25, and M = 0.25. The Young's modulus, was decreased from 5.70 (D/cm2) for S3 to 4.59, 3.14, 2.59, and 3.05 (D/cm2) for S4, S5, S6, and S7. The E g was decreased from 2.13 eV for S3 to 2.16, 2,2, and 1.6 eV for S4, S5, S6, and S7. The pure samples (S1–S3) exhibit ferromagnetic behavior at 300 K, and combination of paramagnetic and ferromagnetic behaviors at 10K. In contrast, the samples (S4–S7) exhibit a combination of paramagnetic and ferromagnetic behaviours at both temperatures. The Curie temperature (T c) obtained through zero-field cooling (ZFC) and field cooling (FC) is close to 300 K for S1–S3, S5, S6, 200 K for S4, and 20 K for S7. The real saturated magnetization (M s) of the ZnO sample was decreased by the addition of SnO 2 , and then increased by the addition of Mn, Ni, Fe, and Co sequentially. M s was increased from 12.31 (emu/g) for S3 at 300 to 16.24, 31.04, 27.27, and 10.49 (emu/g) for S4, S5, S6, and S7, and from 16 (emu/g) to 87, 730, 83, and 29 at 10 K. Remnant magnetization (M r) decreases with the addition of SnO 2 to ZnO and is not affected by the addition of TMs, just in the case of Co, where it increases. The coercive field decreases, but the switching field increases markedly with the addition of Mn and Ni, transforming the system from a hard magnetization to a soft magnetization system. [ABSTRACT FROM AUTHOR]

A medium-entropy fluorite-structured ceramic of (Y 0·25 Zr 0.25 Hf 0.25 Ce 0.25)O 2−δ was prepared using a solid state reaction method combined with conventional sintering at 1600 °C for 10 h. This ceramic has uniform elemental distribution without impurity and segregation. The annealing experiment results show a reversible transformation between single phase and double phases in (Y 0·25 Zr 0.25 Hf 0.25 Ce 0.25)O 2−δ in 800–1600 °C. The reversible phase transformation does not display any obvious influence on the thermal expansion of this sample. The thermal expansion coefficient of (Y 0·25 Zr 0.25 Hf 0.25 Ce 0.25)O 2−δ is 12.4 × 10−6 K−1 in 100–1500 °C, higher than that of 8 wt% yttria-stabilized zirconia (8 YSZ). Furthermore, (Y 0·25 Zr 0.25 Hf 0.25 Ce 0.25)O 2−δ possesses a lower thermal conductivity (1.51 W m−1 K−1 at 900 °C) and higher oxygen barrier property compared with 8 YSZ at high temperature. The Vickers' hardness, Young's modulus and fracture toughness of (Y 0·25 Zr 0.25 Hf 0.25 Ce 0.25)O 2−δ are 10.0 GPa, 193.9 GPa and 1.93 MPa m1/2, respectively. These results demonstrate that (Y 0·25 Zr 0.25 Hf 0.25 Ce 0.25)O 2−δ can be used as a promising candidate ceramic of thermal barrier coatings. [ABSTRACT FROM AUTHOR]

ZnO is one of the most promising mid-high temperature thermoelectric materials because of low cost, easy preparation and favorable chemical stability. Herein, the influence mechanism of Alkaline earth metal Ba doping on the thermoelectric properties of ZnO was studied. It is found that Ba doping can effectively improve the carrier mobility and electrical conductivity for that Ba doping can shorten the Zn–O bond and enhance the overlap and hybridization of electron orbitals. The electronic density of states of Zn and O is significantly enhanced. The highest power factor of ∼7.95 μWcm−1K−2 was obtained at 873 K, which is ∼1.4 times higher than that of the undoped sample. Due to the decrease of Young's modulus caused by Ba doping and the enhancement of phonon scattering of heavy element, the thermal conductivity decreases obviously in the whole temperature range. Ba doping enhanced the effect of phonon glass-electron crystal, and the ZT value of ∼0.345 was obtained at 873 K, which is ∼3.52 times as that of the pristine ZnO. The results indicated that alkaline earth metal doping is an effective way to improve the thermoelectric properties of ZnO functional materials. [ABSTRACT FROM AUTHOR]

In light of increasing apprehensions surrounding the environmental impact of non-biodegradable plastics, there has been a surge in the exploration of biodegradable films as a viable and sustainable alternative. This research has focused on developing Tara gum (TG)-based films incorporated with Lavender essential oil (LEO) at different concentrations (5–20% w/w) to improve the properties of the films. According to the results, GC-MS analysis confirmed the presence of linalool and linalyl acetate as the major compounds in LEO. Among the composite films, the sample containing 5% (w/w) LEO exhibited the highest homogeneity, as evidenced by SEM micrographs, and the CLSM image demonstrated the absence of any clustering or coalescence of LEO within this film. FTIR spectra demonstrated intermolecular interactions between TG and LEO, as evidenced by a new peak at 1458 cm−1 in the LEO-loaded films. The addition of LEO resulted in a significant decrease in the water content (WC) and water solubility (WS) of the films. Furthermore, LEO incorporation improved the contact angle (CA) of the films up to 1.5 times. The TG-LEO films exhibited good transparency, higher elongation at break (EB), and lower Young's modulus (YM). Additionally, LEO positively affected the antioxidant and antimicrobial properties of the films. Overall, the results authenticated the hypothesis of this study and indicated that TG-LEO films have great potential as biodegradable films with promising functionalities for food packaging applications. [ABSTRACT FROM AUTHOR]

Fused deposition modelling (FDM) is a popular additive manufacturing method involving the deposition of a molten filament along a specific path. In this paper, the microstructure and properties of the filament and the printed part are compared to understand the microstructure and property evolution during the printing process. Two commonly used materials Poly-lactic acid (PLA) and carbon fiber-reinforced PLA (CF + PLA) are used for the study. A thorough experimental campaign is undertaken to compare different properties including elastic properties (modulus, ultimate tensile strength, strain to failure), fiber length distribution, fiber orientation distribution, X-ray diffraction (XRD) analysis, and multiscale characterization of damage/mode of failure. The addition of CF reinforcement led to an increase in Young's modulus and a reduction of the tensile strength for both the filament as well as printed coupons. There is extensive microstructural change during the printing process with major fiber breakage and increased misalignment. In general, Young's modulus of the printed part is significantly lower than the filament whereas the strength depends on the printing orientation. Both the filament and printed part display complex modes of failure at multiple length scales. The damage modes for the filament and corresponding printed part are different with a strong dependence on the raster orientation for the latter. XRD confirms somewhat different amorphous behavior for the filament and printed part. [ABSTRACT FROM AUTHOR]

Boron carbide is a notable ceramic, with its high hardness and low density. However, it suffers a sudden loss in strength under high shear stress. Doping boron carbide with Si/B is widely used to increase its resistance to amorphization. High purity boron and silicon hexaboride precursor powders are used for doping boron carbide, but these materials have high costs and supply chain constraints. This research investigated the effect of substituting lower purity B or using pure Si powder instead of SiB6 on materials' properties such as elastic and mechanical properties, microstructure, and amorphization resistances. It was observed that using lower‐purity boron or pure Si powder instead of SiB6 did not significantly affect critical properties, such as fracture toughness, hardness, or amorphization resistance. However, Young's modulus values decreased as B purity decreased and as Si was used instead of SiB6. These findings demonstrate that substituting precursor materials in Si/B co‐doped B4C is possible with little change in the material's properties. This facilitates the use of easier‐to‐access, cheaper production routes to be used for silicon‐doped boron carbide products. [ABSTRACT FROM AUTHOR]

Elastography can be used as a diagnostic method for quantitative characterization of tissue hardness information and thus, differential changes in pathophysiological states of tissues. In this study, we propose a new method for shear wave elastography (SWE) based on laser-excited shear wave, called photoacoustic shear wave elastography (PASWE), which combines photoacoustic (PA) technology with ultrafast ultrasound imaging. By using a focused laser to excite shear waves and ultrafast ultrasonic imaging for detection, high-frequency excitation of shear waves and noncontact elastic imaging can be realized. The laser can stimulate the tissue with the light absorption characteristic to produce the thermal expansion, thus producing the shear wave. The frequency of shear wave induced by laser is higher and the frequency band is wider. By tracking the propagation of shear wave, Young's modulus of tissue is reconstructed in the whole shear wave propagation region to further evaluate the elastic information of tissue. The feasibility of the method is verified by experiments. Compared with the experimental results of supersonic shear imaging (SSI), it is proved that the method can be used for quantitative elastic imaging of the phantoms. In addition, compared with the SSI method, this method can realize the noncontact excitation of the shear wave, and the frequency of the shear wave excited by the laser is higher than that of the acoustic radiation force (ARF), so the spatial resolution is higher. Compared to the traditional PA elastic imaging method, this method can obtain a larger imaging depth under the premise of ensuring the imaging resolution, and it has potential application value in the clinical diagnosis of diseases requiring noncontact quantitative elasticity. [ABSTRACT FROM AUTHOR]

Herein, we conducted tensile and fracture tests on a photopolymer produced with a stereolithography apparatus (SLA), utilizing dog‐bone and semi‐circular bending specimens fabricated in five different orientations. The analysis revealed a direct linear correlation between the tensile strength and printing orientation, highlighting a decrease in tensile strength with an increase in orientation angle. Young's modulus of the printed material remained insensitive to the printing orientation. Conversely, fracture toughness demonstrated a distinct cubic polynomial relationship with the printing orientation. The equivalent material concept in conjunction with the maximum tangential stress criterion was used to predict the fracture behavior of SLA printed polymer. This research sheds light on the significant effect of printing orientation on the mechanical properties of SLA printed materials, offering pivotal insights for optimizing SLA printing across various applications and catalyzing progress in this research field. Highlights: Printing orientation effects were investigated by experimental and numerical methods.Tensile strength, fracture toughness, and crack paths are influenced by orientation angle.Equivalent material concept combining with maximum tangential stress criterion is used to predict the fracture behaviors. [ABSTRACT FROM AUTHOR]

This study examines the effects of minor variations in the building angle of 3D‐printed AlSi10Mg components on mechanical properties under different processing and postprocessing conditions (as‐built [AB], stress relief [SR], and platform heating [HP]). Beginning with tensile tests to determine stress ranges for subsequent fatigue experiments, findings indicate that the building angle significantly impacts tensile strength, yield strength, and ultimate strain, rising with inclining angles. However, Young's modulus remains unaffected. High‐cycle fatigue testing at stress amplitudes below yield strength values reveals differences in S‐N fatigue curves among AB, SR, and HP conditions. While the building angle's influence is not statistically significant, AB samples exhibit lower fatigue resistance than SR and HP counterparts. HP samples perform similarly to SR at high stress levels but notably worse at low stress values. The developed multiple linear regression model shows reasonable accuracy, with 84% of predictions within ±2‐factor and 97.2% within ±3‐factor. Highlights: Tensile strength and ultimate strain increase with inclining building angles.Eighty‐four percent of the predictions of regression model fell within the ±2‐factor error range.The fracture surface shows the crack initiation and propagation area, and the final fracture zone.The fatigue crack originated near the surface shows the presence of multiple initiation spots. [ABSTRACT FROM AUTHOR]

Surface acoustic wave spectroscopy has been established as non‐destructive and fast method for characterization of mechanical properties of surfaces and bulk materials in both research and industry. The present work shows that by application of a novel and robust aluminum nitride (AlN) coated piezoelectric contact sensor the advantages of the method can be extended from room temperature to at least 600°C. An overview of sensor concepts and applications of the method is discussed first, followed by theoretical and practical considerations for design and coating of a novel temperature stable contact sensor. After fabrication of such a sensor using magnetron sputtering, it was tested in a modified surface acoustic wave spectroscopy setup with an incorporated heating table concerning signal amplitude and frequency range. The AlN coated sensor was found to perform well up to 600°C, with temperature limited by the specification of the heating table. At room temperature, performance was acceptable when compared with a conventional contact sensor using a PVDF piezoelectric foil. Application of the high temperature capabilities of the setup was demonstrated by measuring temperature stability of hydrogen‐free amorphous carbon coatings (a‐C and ta‐C) depending on their sp3 carbon ratio. In another example, high precision temperature dependent measurement of Young's modulus for ultrasonic fatigue test specimen was taken, achieving an accuracy better than 1%. Use of the developed sensor opens up new possibilities in material science for in situ study of temperature depending mechanical properties for coatings and surfaces. [ABSTRACT FROM AUTHOR]

Cu-containing silicon oxycarbide (SiOC) ceramic composites have been prepared by thermal pyrolysis of polymeric precursors and subsequent spark plasma sintering at 1600 °C. The resulting composites consist of SiO 2 , SiC, free carbon, and Cu-Si alloys. The microstructure of the composites has been identified via optical microscope and SEM. The mechanical properties, including the Vickers hardness, nano-indentation hardness, and Young's modulus, of the SiOC composites have been assessed via indentation methods. The effects of Cu content on the tribological properties of the composites have additionally been investigated under different sliding frequencies against Al 2 O 3 spheres at room temperature. It is shown that the introduction of the Cu-Si alloys is effective in reducing the friction coefficient of the material system, which decreases linearly from 0.27 of monolithic SiOC to 0.15 of SiOC with 7 wt% Cu content at 1 Hz. Raman spectroscopy has highlighted the friction-driven evolution of the free carbon phase in the SiOC ceramics. Finally, a correlation between the sliding frequency, Cu-Si content, and tribological properties of SiOC is established. [ABSTRACT FROM AUTHOR]

Graphite is a widely used oxygen impurity-removing additive and a property-tuning second phase for diboride and carbide-based ultrahigh temperature ceramics (UHTCs). In recent years, high-entropy diboride (HEB) ceramics have attracted much attention for the development of better UHTCs. However, oxide impurity generally inhibits their densification and harms their properties. Here, (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2)B 2 ceramics added with different contents of graphite (HEB- x C, x = 0, 1, 2.5, 5, 10, 20 vol%) were prepared by spark plasma sintering. It was found that the added graphite acted as an oxygen-removing agent and the oxide impurity phase t -(Zr, Hf)O 2 was converted to the (Hf, Ta)C-based solid solution carbide. With the increase in graphite content, the relative density increased from 89.4% for HEB-0 C to 100% for HEB-10 C. Based on the evaluated properties of the prepared specimens, including Young's modulus, hardness, toughness, and thermal conductivity, the added graphite with an optimized content is important for a given started powder and processing to achieve good and balanced material properties. [ABSTRACT FROM AUTHOR]

A new nine-principal cation high-entropy oxide of (Y 1/9 La 1/9 Nd 1/9 Sm 1/9 Yb 1/9 Lu 1/9 Eu 1/9 Gd 1/9 Ce 1/9) 2 O 3 (9HEO) was synthesized by co-precipitation method combined with conventional sintering at 1600 °C for 10 h. Two samples of 9HEO-(Ce3+) and 9HEO-(Ce4+) were obtained by adjusting the valence state of Ce element in 9HEO. The ratio of Ce3+ to Ce4+ in 9HEO-(Ce3+) and 9HEO-(Ce4+) is approximately 2:1 and 14:15, respectively. These two samples have the same bixbyite structure and similar microscopic morphology. Their relative density, thermal expansion coefficient, hardness and Young's modulus are close. The higher ratio of Ce3+/Ce4+ in 9HEO-(Ce3+) leads to the expansion of its lattice volume and the decrease of thermal conductivity (κ) compared with 9HEO-(Ce4+). In addition, the κ values of these two samples are lower than those of Y 2 O 3 and (Eu 0.2 Er 0.2 Lu 0.2 Y 0.2 Yb 0.2) 2 O 3 , which have a bixbyite structure and lower entropy. 9HEO-(Ce3+) and 9HEO-(Ce4+) show higher oxygen barrier property compared with Y 2 O 3 -stabilised ZrO 2. [ABSTRACT FROM AUTHOR]

Thermal barrier coatings (TBCs) utilized for thermal insulation in gas turbines are typically semitransparent to infrared thermal radiations, resulting in a limited thermal insulation performance. In this study, plasma spraying TBCs with intra-splat spherical pores (SPs) are designed and prepared by the oxidation of micro carbon spheres particles. SPs with diameter of 0.5–1.5 µm remarkably improve the scattering coefficients (1.9 times vs conventional coating) and reduce the thermal conductivity of TBCs, leading to a temperature drop of 79.8 K at coating/substrate interface. The coatings with SPs in micrometers also exhibit excellent anti-sintering behavior. The average reflectance in 1.0–1.8 µm of coatings with SPs keep almost unchanged after heated at 1300 °C for 80 h. As SPs are wrapped by YSZ laminar splats, the embedded SPs shows neglectable decrease (<10%) in Young's modulus and hardness to the coating. [Display omitted] [ABSTRACT FROM AUTHOR]

The strategic design of solution‐processable semiconducting polymers possessing both matched energy levels and elevated glass transition temperatures is of urgent importance in the progression of thermally robust n‐i‐p perovskite solar cells with efficiencies exceeding 25 %. In this work, we employed direct arylation polymerization to achieve the high‐yield synthesis of three aza[5]helicene‐derived copolymers with distinct HOMO energy levels and exceptional glass transition temperatures. Upon integration of these semiconducting polymers into formamidinium lead triiodide‐based perovskite solar cells, marked disparities in photovoltaic parameters manifest, primarily stemming from variations in the electrical conductivity and film morphology of the hole transport layers. The p‐A5HP‐E‐POZOD‐E copolymer, featuring a main chain comprising alternating repeats of aza[5]helicene, ethylenedioxythiophene, phenoxazine, and ethylenedioxythiophene, attains an initial average efficiency of 25.5 %, markedly surpassing reference materials such as spiro‐OMeTAD (23.0 %), PTAA (17.0 %), and P3HT (11.6 %). Notably, p‐A5HP‐E‐POZOD‐E exhibits a high cohesive energy density, resulting in enhanced Young's modulus and diminished external species diffusion coefficients, thereby conferring perovskite solar cells with exceptional 85 °C tolerance and operational stability. [ABSTRACT FROM AUTHOR]

This study introduces a new approach for introducing a bidirectional elastic modulator that operates for acoustic systems in the megahertz frequency range. The proposed modulator combines a Mach–Zehnder interferometer (MZI) with a magnetic material within a solid–solid phononic crystal (PnC). In fact, a new method has been developed to manipulate the interference of acoustic waves utilizing a magnetic field in a distinctive PnC-MZI configuration. This suggested modulator is simple and convenient for application in acoustic communication systems and networks. The PnC structure comprises a square lattice composed of Tungsten cylinders embedded in a PMMA substrate. The Mach–Zehnder interferometer consists of two symmetrical arms, with each arm containing an embedded Terfenol-D material. The proposed modulator operates dynamically by altering the Young's modulus of Terfenol-D through the application of an external magnetic field. By considering three different values of Young's modulus for the Terfenol-D hollow cylinders in the two arms, distinct phase shifts for propagating waves are achieved, resulting in three levels of intensity in the modulator's output in the proposed modulator. Another advantage of the proposed configuration is its bidirectional functionality. Furthermore, the modulator demonstrates a high extinction ratio of − 22.2 dB and a low insertion loss of 0.4 dB, indicating its excellent performance. The simulations are fulfilled using the finite element method. [ABSTRACT FROM AUTHOR]

Synthetic plastic is the most anxious polymer in packing industry due to its non-biodegradability and biogeomagnification in the ecosystem. In light of the growing worldwide concern over synthetic polymers, natural and semi-synthetic biodegradable packaging materials with microbicide properties are receiving more attention in the food industry. The current research emphasises on the idea to convert a waste aquatic weed in to an advantageous eco-friendly substitute to a harmful biomagnifying food packing material. Water weed Eichhornia crassipes was used for the formation of hybrid films with nanocellulose and nanoclay coupled with green synthesised zinc oxide nanoparticles (NPs) by C. fistula fruit extract. Physicochemical properties of the starch-based binary nanocomposite (BNC) as well as ternary nanocomposite (TNC) were confirmed by TGA, DSC, SEM, EDX, FTIR and XRD analyses. The mechanical properties of both BNC and TNC were evaluated for its tensile strength, Young's modulus and elongation break analysis. Further, the established ternary nanocomposite film with 2% ZnO NPs showed better surface morphology compared to the control binary films. Microbial efficacy studies revealed that the synthesised films are microbicidal in nature against foodborne pathogens Escherichia coli, Botrytis cinerea and Sclerotium rolfsii. The overall study accentuates that the green-based nanocomposites are eco-friendly, economically feasible and act as an effective route to overcome foodborne pathogens conferring them to be an alternative to petrochemical-based product. [ABSTRACT FROM AUTHOR]