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Depending on high permeability, high Curie temperature, and low eddy current loss noise, nanocrystalline alloys, as the innermost layer, exhibit great potential in the construction of cylindrical magnetic shielding systems with a high shielding coefficient and low magnetic noise. This study compares a magnetic noise of 1 Hz, simulated by the finite element method (FEM), of a cylindrical nanocrystalline magnetic shield with different structural parameters based on the measured initial permeability of commercial Fe-based nanocrystalline (1K107). The simulated results demonstrate that the magnetic noise is irrelevant to the pump and probe hole diameter. The magnetic noise of a nanocrystalline cylinder with a fixed length gradually increases with the rise in aspect ratio. The radial and axial magnetic noise of a nanocrystalline cylinder with a fixed diameter can reach optimal values when the aspect ratio is 1.3 and 1.4, respectively. The layer thickness of a nanocrystalline cylinder is negatively correlated to magnetic noise. Additionally, by comparing the 1 Hz magnetic noise of a cylindrical nanocrystalline magnetic shield with varying initial permeability, it can be concluded that an increase in loss factor results in an increase in magnetic noise. These results are useful for the design of a high-performance passive magnetic shield with low magnetic noise. [ABSTRACT FROM AUTHOR]

In the present work, commercially pure aluminum (Al) powders were milled at cryogenic temperatures (a) without magnesium (Mg) and (b) with 5 wt.% Mg powders for different durations. The cryomilled powders were analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray diffraction (XRD) to determine the changes in particle morphology, elemental composition, and crystallite size. The results showed a reduction in crystallite size with the increase in cryomilling duration. Thereafter, the spark plasma sintering (SPS) process was carried out to manufacture bulk samples. The mechanical properties of the bulk SPS samples were assessed by conducting microhardness, tensile, and fatigue tests. The Vickers microhardness tests showed improved hardness for the Al-Mg bulk samples as compared to pure Al. The Al-Mg samples also showed an increase in tensile strength with increasing cryomilling time. Fatigue test results showed an improvement in Al-Mg components' high-cycle fatigue response. The mechanism for the enhancement in mechanical properties as a result of crystallite size reduction and grain boundary strengthening by the addition of Mg dopant is also discussed. [ABSTRACT FROM AUTHOR]

Deformation of nanocrystalline materials often involves the grain boundary (GB) dominated creep process. However, the atomistic mechanism of diffusional mass transport along GB remains unclear. Here, we presented a mechanism of stress-driven diffusional climb of GB dislocations in gold (Au) nanocrystals by in-situ nanomechanical testing. Successive proceeding of GB dislocation climb enhances the mass transport along GBs and contributes to a Coble-type GB deformation at room temperature. These findings provide insights into the GB-dominated diffusional plasticity in nanocrystalline materials and are of significance for the creep deformation of nanocrystalline materials. [ABSTRACT FROM AUTHOR]

In this work, the Al-Mo nanocrystalline alloy films with Mo contents ranging from 0–10.5 at.% were prepared via magnetron co-sputtering technology. The composition and microstructure of alloy thin films were studied using XRD, TEM, and EDS. The mechanical behaviors were tested through nanoindentation. The weights of each strengthening factor were calculated and the strengthening mechanism of alloy thin films was revealed. The results indicate that a portion of Mo atoms exist in the Al lattice, forming a solid solution of Mo in Al. The other part of Mo atoms tends to segregate at the grain boundaries, and this segregation becomes more pronounced with an increase in Mo content. There are no compounds or second phases present in any alloy films. As the Mo element content increases, the grain size of the alloy films gradually decreases. The hardness of pure aluminum film is 2.2 GPa. The hardness increases with an increase in Mo content. When the Mo content is 10.5 at.%, The hardness of the film increases to a maximum value of 4.9 GPa. The fine grain ( ∆ H g b ), solid solution ( ∆ H s s ), and nanocrystalline solute pinning ( ∆ H n c , s s ) are the three main reasons for the increase in the hardness of alloy thin films. The contribution of ∆ H g b is the largest, accounting for over 60% of the total, while the contribution of ∆ H s s accounts for about 30%, ranking second. The rest of the increase is due to ∆ H n c , s s . [ABSTRACT FROM AUTHOR]

In this work, we provide a theoretical framework to evaluate the beneficial effect of solute segregation on the creep behaviour of nanocrystalline materials. We choose copper as the model system and employ the Murdoch and Schuh model to identify Cu–3Zr as a binary system with high thermal stability in its nanocrystalline state. The effect of the segregation of Zr on the grain boundary diffusivity was evaluated using the Hondros and Henderson model. The effect of solute segregation on threshold stress for vacancy emission and absorption at the grain boundaries was evaluated using the Mohamed model. Using these in conjunction with the Bird Mukherjee Dorn equation for creep allowed us to compare the diffusional creep behaviour of nc copper and nc Cu–3Zr. The nc Cu–3Zr system with a grain size of 49 nm demonstrated a higher creep resistance compared to nc Cu bearing a similar grain size. However, the creep resistance of both systems was found to be significantly inferior when compared to the conventional coarse-grained Cu bearing a grain size of 1 μm. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) with ultrafine grained and high strength can be prepared by mechanical alloying (MA) followed by sintering. Therefore, MA, as a unique solid powder processing method, has many effects on the microstructures and mechanical properties of the sintered bulk HEAs. This work focused on the alloying behavior, morphology, and phase evolution of FexCrNiAl (x = 1.0, 0.5, 0.25) HEAs by MA. The X-ray diffraction results show that the powders achieved a supersaturated solid solution body-centered-cubic (BCC) phase after MA; the crystalline size reached the nanoscale and was refined to ~80 nm. The morphology and composition of the alloyed powders were studied by scanning electron microscopy with energy dispersive spectroscopy. The results indicate that the powder was decreased to 1.59 μm for Fe1.0 powder with excellent homogeneity in composition. There exists a phase transformation during high-temperature annealing, as the non-equilibrium BCC supersaturated solid solution phase transformed into the equilibrium phase of BCC and ordered BCC (B2) phases. [ABSTRACT FROM AUTHOR]

Reactive inks are an attractive method to selectively pattern metallic features with minimal post-processing. While significant progress has been made developing silver and copper reactive inks for printed electronics, less progress has been made in developing metal reactive inks with properties suitable for structural or magnetic applications. To address this gap, this work introduces particle-free iron and cobalt metal reactive inks to print magnetic iron and cobalt metals. Interestingly, structure analysis of the printed reactive inks showed that the iron reactive ink produced fully amorphous iron and the cobalt reactive ink produced nanocrystals dispersed in an amorphous matrix. This work also demonstrates two combinatorial methods of printing these inks: by mixing the two inks together to produce amorphous iron–cobalt alloys and by spatially patterning the iron and cobalt monometallic inks to achieve control over both the local composition and the correlated atomic structure. Triiron dodecacarbonyl and dicobalt octacarbonyl are used as the iron and cobalt metal precursors, respectively, because these zerovalent metal complexes directly decompose to metal and carbon monoxide gas. The printed metals' elemental and chemical compositions were evaluated using energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Mössbauer effect spectroscopy showing that the amorphous phases are likely stabilized by either remnant carbonyl bonds from incomplete decomposition of the metal carbonyl or residual octylamine solvent interacting with the metal atoms. Additional characterization includes resistivity measurements to verify metallic conductivity, nanoindentation to quantify hardness, and magnetometry studies to quantify the magnetic performance. As a demonstration, the Fe and Co reactive inks were sequentially printed in a combinatorial layer-by-layer manner to produce a vertically graded iron and cobalt line, as well as a matrix of nanocrystalline cobalt dots on an amorphous iron film. Overall, this work introduces a method to directly print continuous, amorphous, magnetic, and structural alloys at moderate temperatures from a particle-free reactive ink. [ABSTRACT FROM AUTHOR]

Pure, 1% Cu doped and 5% Cu doped tungsten oxide dihydrate () nanocrystalline materials have been prepared by the chemical co-precipitation method. The materials have been characterized by various techniques viz. X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray (EDX) spectrometer and UV-visible spectrophotometer. The effectiveness of the materials for the removal of rhodamine B (RhB) dye from aqueous solution has been investigated. The crystal structure and particle morphology of the synthesized nanocrystals have been found to be monoclinic and platelike, respectively. The crystallite sizes of the pure, 1% Cu doped and 5% Cu doped nanocrystals are 55 nm, 54 nm and 55 nm, respectively. The pure and Cu doped nanocrystals have been found to be good adsorbing materials of RhB dye. Doping of Cu has been found to enhance the adsorption efficiency of . The 1% Cu doped exhibited the highest RhB dye removal efficiency of 72% (after 6 h of contact with the dye) among the materials investigated. The Langmuir isotherm model has been found to describe the adsorption behaviour better than the Freundlich isotherm model for the 1% Cu doped nanocrystals. The materials investigated in the present work are found to be promising adsorbents for the removal of RhB dye from aqueous solution. [ABSTRACT FROM AUTHOR]

The cytological behaviour and functional dynamics (adhesion, spreading, synthesis of proteins) of fibroblasts when interacting with biomedical surfaces are intricately influenced by the inherent nature of surface (nanocrystalline or microcrystalline), where the nanocrystalline (NC) surface is preferred in relation to the microcrystalline (MC) surface. This preference is a direct consequence of the distinct differences in physical and chemical characteristics between NC and MC surfaces, which include crystal boundary bio-physical attributes, electron work function, surface energy, and charge carrier density. The observed variances in cytological behaviour at the interfaces of NC and MC bio-surfaces can be attributed to these fundamental differences, particularly accounting for the percentage and nature of crystal boundaries. Recognising and understanding these physical and chemical characteristics establish the groundwork for formulating precise guidelines crucial in the development of the forthcoming generation of biomedical devices. HIGHLIGHT POINTS: The significance of nanoscale surface in favourably modulating the cellular functionality is described with the aim to provide the solution to the current day challenges in the biomedical arena. Furthermore, the perspective presented advances the nano-bio science forward by implying that the nanoscale structure induces chemical and physical changes that can be considered responsible for favourable modulation of cellular activity in the living organism. [ABSTRACT FROM AUTHOR]

The primary objective here is to underscore the significance of high percentage of crystal boundaries (>50%) of a nanocrystalline (NC) surface in understanding the cellular interaction of fibroblasts with the NC surface of biomedical stainless steel. The favourable cellular functions on the NC surface as compared to the conventional microcrystalline (MC) surface with ~2–3% crystal boundaries are related to the bio-physical characteristics of the crystalline surface. The unveiling of bio-physical characteristics in terms of crystal boundaries is one of the relevant aspects that provides an understanding of the preferred biological functions, notably, cell adhesion, spread and synthesis of proteins on the NC surface in relation to the MC counterpart. [ABSTRACT FROM AUTHOR]

Thermo-mechanically stabilized nanocrystalline (NC) alloys are increasingly valued for their enhanced mechanical strength and high-temperature stability, achieved through thermodynamic and kinetic stabilization methods. However, their fine-grained structure also increases susceptibility to internal oxidation due to higher atomic diffusivity associated with a greater volume fraction of grain boundaries (GBs). By incorporating solutes that form protective oxides, or the so-called thermally growing oxides (TGO), this vulnerability can be mitigated. The TGO scale acts as a diffusion barrier for oxygen that slows down the oxidation kinetics and prevents internal oxidation that impairs the structural integrity of the metal. This review examines advancements in oxidation-resistant NC alloys, focusing on the interplay between grain size and alloy chemistry. We explore how grain refinement influences diffusion coefficients, particularly the enhanced GB diffusion of Ni and Cr in Ni-Cr-based alloys, which improves oxidation resistance in NC variants like Ni-Cr and Cu-Cr compared to coarse-grained counterparts. We also analyze the role of third elements as oxygen scavengers and the impact of reactive elements such as Hf, Zr, and Y in NiAl alloys, which can slow down diffusion through early establishment of protective TGO layers and enhance oxidation resistance. The concomitant effect of grain size refinement, modifications in alloy stoichiometry, and enhanced atomic diffusion is shown to manifest via drastic reductions in oxidative mass gain, and visualization of the stable, protective oxide scales is delivered through characterization techniques such as TEM, SEM, and EDS. A brief overview is provided regarding stress effects and the role of induced stress in driving oxide scale spallation, which can negatively impact oxidation kinetics. Lastly, we propose future research directions aimed at developing micro-structurally stable NC alloys through multi-solute strategies and surface modification techniques, targeting robust materials for high-stress applications with improved oxidation resistance. [ABSTRACT FROM AUTHOR]

NiTi based memory alloys have a narrow super-elastic temperature range (<100 °C), which limits their application range. In this paper, nanocrystalline (NC) Ni51Ti49V1 (at.%) alloy wire was prepared by Ni-V co-doped NiTi through vacuum induction melting, forging, large deformation wire drawing and low temperature annealing. The microstructure of the sample was characterized by transmission electron microscopy (TEM), and the superelasticity of the sample was characterized by universal tensile testing machine. The results showed that Ni51Ti49V1 alloy consists of nanocrystalline with an average grain size of 13 nm. Tensile tests at different temperatures showed that the alloy exhibited excellent superelasticity in a wide temperature range from -40 °C to 100 °C, and the superelastic temperature range was wider than that of NC NiTi alloy (25-100 °C). In addition, the temperature dependence of the critical stress of the B2→B19′ transformation (dσ/dT) decreased from 5.6 MPa/°C to 1.8 MPa/°C with decreasing temperature. [ABSTRACT FROM AUTHOR]

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

This paper describes the chemical synthesis of nanocrystalline CuS thin films onto glass substrate at 40 ℃. The effect of the deposition time on the Raman spectroscopy results and physical properties was investigated. X-ray diffraction pattern showed the amorphous nature of CuS thin films deposited with deposition time of 20 min and transferred to orthorhombic crystal structure for CuS thin films with deposition time of 40 min. Raman modes observed at around 273 cm – 1 and 475 cm– 1 in CuS thin films support the formation of covellite CuS phase. FESEM images taken from the surfaces of chemically deposited nanocrystalline CuS thin films shows the dense structure, smooth and relatively void-free surfaces and surface looks well adhered to the glass substrate. The optical band gap was estimated to be in the range between 2.05 eV and 2.15 eV depending on the deposition time. Finally, as a result of the analysis, we can say that the variation in deposition time can affect the structural properties of CuS thin films. [ABSTRACT FROM AUTHOR]

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

Due to its promising features, cellulose, the most plentiful renewable material in nature, is used in a variety of industrial processes. In this work, we used peanut shells (Arachis hypogaea L.) for the purpose of producing microcrystalline cellulose (MCCs) and nanocrystalline cellulose (CNCs), respectively. The following process was used to separate cellulose from peanut shells: dewaxing, delignification/bleaching, and acid hydrolysis. The structural features of the isolated microcrystalline cellulose (MCCs) and cellulose nanocrystalline (CNCs) samples were tested by Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was used to morphologically analyze of the samples (peanut shells, microcrystalline cellulose, and nanocrystalline cellulose). The prepared CNCs' elemental composition was revealed by energy dispersive X-rays (EDX), and their crystallinity was shown by X-ray diffraction (XRD). The yield of peanut shells cellulose was (31.81%). FTIR analysis for the bleached peanut shells cellulose revealed the efficacious removal of the non-cellulosic materials and amorphous components from the polymer matrix. The obtained peanut shells' XRD results showed native cellulose's typical peaks (type I), along with a crystallinity index (CrI = 72.53%). Also, acid hydrolysis phase was used to adapt microcrystalline cellulose (MCCs) into cellulose nanocrystalline (CNCs) with higher crystallinity (CrI = 77.96%). According to each of these assays, the chemical treatment was successful in eliminating the non-cellulosic substances and obtaining a cellulose nanofiber.The antibacterial activity carried out against three bacterial strains (Staphylococcus aureus, Escherichia Coli, and Salmonella typhimurium) that cellulose nanofibers showed moderate antibacterial activity against a strain Staphylococcus aureus and Salmonella typhimurium.The current study demonstrates the viability of employing peanut shells as a cost-effective source for acquiring CNCs that are intended for use in the food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

This study investigates the effects of multi-transition metals on the soft magnetic properties of Fe73.5−xB9Si14Cu1Nb2.5Mx (M = Nb, Mo, and W) nanocrystalline soft magnetic alloys. Nanocrystalline soft magnetic materials are utilized in electronic components on the basis of their permeability and low core loss. In conventional alloys such as FINEMET, Nb inhibits nanocrystal growth and promotes amorphous formation. In this research, Mo and W were used as additional transition metals to control the size of nanocrystals and explore the potential for enhancing soft magnetic properties. We confirmed that the addition of Mo and W reduced the nanocrystal size, and the activation energy for nanocrystal formation and growth showed significant benefits for nanocrystalline alloys. Consequently, the soft magnetic properties of the alloys containing Mo and W exhibited higher permeability and lower coercivity. These results suggest that multi-transition metals are effective in improving soft magnetic properties by inhibiting nanocrystal formation and growth. [ABSTRACT FROM AUTHOR]

Deformation of nanocrystalline materials often involves the grain boundary (GB) dominated creep process. However, the atomistic mechanism of diffusional mass transport along GB remains unclear. Here, we presented a mechanism of stress-driven diffusional climb of GB dislocations in gold (Au) nanocrystals by in-situ nanomechanical testing. Successive proceeding of GB dislocation climb enhances the mass transport along GBs and contributes to a Coble-type GB deformation at room temperature. These findings provide insights into the GB-dominated diffusional plasticity in nanocrystalline materials and are of significance for the creep deformation of nanocrystalline materials.

The molecular dynamics method was used to simulate the microstructure dynamic evolution， dislocation， and pore motion characteristics of AlCoCrFeNi high-entropy alloy at temperature 300 K and strain rate of 1×109 s-1， and the failure mechanism was revealed. The simulation results show that the maximum load-bearing， longitudinal modulus， and ductility of the nano-polycrystalline AlCoCrFeNi high-entropy alloy are lower than those of nano-monocrystalline. The strain reduction and peak stress reduction of nano-polycrystalline before yield are 25% and the peak stress reduction is 23.8%. The phase transition， dislocation， hole， and failure mechanism of the two nanocrystallines are different during the stretching process. During the stretching process of nano-monocrystals， the FCC structure is mainly transformed into a non-crystalline structure. The atomic position changes after the phase change， accompanied by a large number of Shorkly dislocations， and moves with the growth direction of the non-crystalline structure. The hole nucleation， growth， penetration， and failure fracture of non-crystalline structure area are mainly amorphous perforation fault. During the stretching process of nano-polycrystalline， the FCC structure mainly transforms to HCP structure and non-crystalline structure， and the atomic position changes after the phase change， accompanied by a large number of 1/6〈112〉 （Shortly） dislocations and a small number of 1/6〈110〉 （Stair-rod） dislocations， 1/3〈100〉 （Hirth） dislocations， and other dislocations continue to be generated and annihilated.The material undergoes certain plastic deformation， with nucleation of pores in the non-crystalline structure area of the grain boundary， growth and expansion along the grain boundary， and penetration through the grain boundary until failure fracture， showing mainly intergranular fracture.

This research investigates the structural, morphological, and optical properties of SnO2 and Cu-doped SnO2 films deposited on glass and FTO substrates using the RF sputtering technique. The Cu-doped samples were subsequently annealed in an oxygen flow at temperatures of 400 and 500 °C. X-ray diffraction (XRD) analysis revealed that pure SnO2 thin films exhibited an amorphous structure on both substrates. In contrast, the Cu-doped SnO2 sample on the glass substrate maintained its amorphous state, while the sample on the FTO substrate transitioned to a tetragonal rutile structure. Thermal annealing further induced a transformation to a tetragonal rutile structure for samples on both substrates. Energy dispersive spectroscopy (EDS) confirmed the incorporation of Cu into the SnO2 films. The estimated crystallite sizes ranged from 16 to 20 nm for the glass substrate and from 20 to 31 nm for the FTO substrate. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) analyses demonstrated uniform surface morphology with a smooth texture and strong adhesion to the substrates. The band gap energy (Eg) values for the unannealed samples were found to be 3.52, 3.40, 3.50, and 3.29 eV. Notably, Cu doping and the deposition of SnO2 films on FTO substrates resulted in a reduction of the band gap. These findings provide valuable insights into the effects of Cu doping, annealing, and substrate type on the structural and optical properties of SnO2, paving the way for advanced optoelectronic applications. [ABSTRACT FROM AUTHOR]

The effect of the grain size on the dielectric properties and electrical conductivity was studied for single-phase solid solution of the ZrO2–CeO2 system with 75% CeO2. The bi-ceramic composition of ZrO2–CeO2 as Ce0.75Zr0.25O2 was prepared through a solid-state reaction to synthesize single-phasic material followed by high-energy ball milling to make finer particle size. Structural properties were confirmed through advanced analytical techniques such as XRD and Raman spectroscopy. SEM confirmed large porosity with a grain size of 204 ± 3 nm, which is larger than the crystallite size of 22.64 ± 8.6 nm calculated from the XRD analysis for Ce0.75Zr0.25O2. The dielectric measurements were performed as a function of temperature by impedance spectroscopy. The relative dielectric constant decreases on increasing frequency for all temperatures, which validates the polar nature of nanocrystalline Ce0.75Zr0.25O2 ceramic. In addition, temperature-dependent enhancement in ε r is more pronounced in low-frequency regions due to low-frequency dielectric dispersion phenomena. The dielectric loss also increases with increasing temperature over the frequency region from 100 Hz to 2 MHz. The electrical conductivity of nanocrystalline Ce0.75Zr0.25O2 was found to be smaller than the micron-sized sample of Ce0.75Zr0.25O2. The present study revealed the crucial role of grain size in tuning the dielectric properties of Ce0.75Zr0.25O2 along with ac conductivity. [ABSTRACT FROM AUTHOR]

The performance of plasma sprayed thermal barrier coatings (TBCs) is strongly dependent on the quality of the feedstock powders, which usually are fabricated by conventional spray drying and multi-step sintering methods. In this work, a novel supersonic plasma spheroidization technology was employed to fabricate the spherical nanocrystalline Sc 2 O 3 -Y 2 O 3 co-stabilized ZrO 2 (ScYSZ) powder. The deformation process from the irregular powder to the spherical one was stimulated by the COMSOL phase field simulation. The results suggested that the original irregular pyrolysis products of ScYSZ precursors were aggregated into spherical powders by plasma spheroidization technology. The COMSOL simulations verified that the powder changed from irregular particles to spherical ones. The spheroidized ScYSZ particles exclusively consisted of non-transformed t' -ZrO 2 phase and showed good fluidity, smooth surface and high apparent density, which were expected to have a broader application prospect in the field of TBCs and other ceramic coatings. [ABSTRACT FROM AUTHOR]

Herein, microwave plasma nitriding (MPN) was employed to fabricate a nanocrystalline tantalum nitride (Ta–N) layer with enhanced mechanical and tribological performance. The results revealed that the nitrogen content in the Ta–N layer appeared as a gradient distribution, resulting in a component gradient structure comprising Ta 2 N, a solid solution of N in Ta and superlattice TaN 0.04 from the top surface to the matrix, which was advantageous for relaxing the stress between the top Ta–N layer and the matrix. Nanocrystalline Ta–N layers (D (avg) = 45–55 nm) with dense and smooth surfaces were obtained at ≤950 °C, while grains grew and pores appeared on the surface of the Ta–N layers (D (avg) = 195–205 nm) at >950 °C. Consequently, the nanocrystalline Ta–N layer with gradient structure and desired thickness exhibited robust hardness and modulus of 26.89 and 247.64 GPa, respectively, which were considerably higher than those prepared by traditional gas/ion/liquid nitriding. The friction and wear test results showed that compared with pure Ta, the MPN-treated Ta matrix exhibited a shallower wear track, lower wear volume, and smaller superficial area, indicating that the Ta–N layer offered excellent surface protection for the matrix. [ABSTRACT FROM AUTHOR]

High Entropy Alloys (HEAs) have become the most researched structural materials in the scientific community during the last decade due to their attributes like excellent strength and wear resistance. In this research, CrCuFeNiZn HEA was prepared using mechanical alloying technique. Further, X-ray diffraction (XRD) and Scanning electron microscope (SEM) analysis of prepared HEA were carried out at various milling time intervals (10 min, 5 h, 10 h, 15 h, 20 h, and 25 h) to determine solid solution formation. Results manifest that CrCuFeNiZn HEA exhibited BCC + FCC (dual phase) structure after 25 h of milling. Moreover, the crystallite size as measured from the XRD analysis for the 25 h milled powder was found to be 32.8 nm and lattice strain at the end of milling is calculated to be 0.428%. SEM-EDS analysis further confirms the homogeneous distribution of the constituting elements in the as-fabricated alloy aggregate. [ABSTRACT FROM AUTHOR]

Hydrogen production from water splitting is considered the most environment-friendly and sustainable method to acquire energy. Alkaline water electrolysis has been widely employed for hydrogen production, but it is still challenging to prepare non-precious metals electrocatalysts to replace the noble-metal-based catalysts. Here we proposed electroless method to prepare a NiCoP nanocrystalline thin flim as efficient electrocatalysts. The morphology and mechanisms of the 45-minute alloy films deposited on Cu substrate were characterized by SEM, XRD, and XPS techniques, moreover, LSV, EIS, and CP were applied to analyze the electrochemical behavior. The nanocrystalline NiCoP45min alloy exhibits higher hydrogen evolution reaction (HER) activity than platinum sheet. An overpotential of -98 mV and a Tafel slope of 47.94 mV·dec−1 at 10 mA·cm−2 was achieved with the catalyst during HER in an alkaline medium. Additionally, its excellent catalytic activity is confirmed by a low Rt value 2.48 Ω. Remarkably, this catalyst also exhibits high HER stability for about 45 h in an alkaline electrolysic solution. [ABSTRACT FROM AUTHOR]

Soft magnetic films play a crucial role in numerous technological applications, such as magnetoelectronics, telecommunications, and magnetic recording, and the tuning of properties to obtain high-efficiency demands searching new materials and controlling thickness and compositions. In this regard, we report a systematic investigation of structural, morphological, electrical resistivity, and temperature-dependent magnetic properties of single-layer amorphous Fe70Co15Zr7B5Cu3 HITPERM (t = 5–100 nm) films deposited on a low-cost thermally oxidized Si substrate. Structural studies (XRD and TEM) reveal an amorphous nature in all as-deposited films. Surface morphology shows that the average roughness increases with increasing t up to 50 nm and then decreases at higher thicknesses. The electrical resistivity decreases rapidly as t increases from 5 to 10 nm and then is invariant for films with t ≥ 30 nm. Interestingly, the variation of resistivity follows the Boltzmann fitting. These films exhibit tunable magnetic properties between soft (t < 20 nm) and semi-hard (20 nm < t < 70 nm) properties with rectangular-type magnetic hysteresis loops having ~ 100% remanence ratios (Mr/Ms), low coercivity (Hc < 2.5 kA/m), and low saturation magnetic field (Hs < 3 kA/m) for t ≤ 70 nm. Transcritical hysteresis loop with a large Hc > 6.7 kA/m, high Hs > 26.5 kA/m, and reduced Mr/Ms ~ 55% is observed for t = 100 nm film. High-temperature thermomagnetization curves display two magnetic phase transitions (TC) corresponding ferromagnetic state to a paramagnetic state of the amorphous phase (at 820 K during warming) and nanocrystalline phase (at 1003 K during cooling). The observed results of HITPERM films with large TC naturally make it a potential choice for applications not only in magnetoelectronics at room temperature but also for aircraft power devices at higher temperatures. [ABSTRACT FROM AUTHOR]

In this study, bulk nanocrystalline material is fabricated from Inconel 718 powder through a process of powder high‐pressure torsion (HPT) and subsequent annealing heat treatment. Numerous dislocations generated during the powder HPT process successfully produced bulk Inconel 718 with nanocrystalline grains during the post‐annealing treatment. In addition, the Inconel 718 exhibited additional strengthening contributions such as dislocation strengthening by high pre‐existing dislocation density and precipitation strengthening from randomly distributed precipitates. As a result of these strengthening effects, the Inconel 718 showed ultrastrong yield strength of 1.40 GPa and ultimate tensile strength of 1.53 GPa. Although the elongation of 12.0% did not indicate good ductility, the proposed Inconel 718 boasted improved mechanical properties compared to previous studies of Inconel 718 fabricated by various processing methods. The prepared Inconel 718 and its fabrication technique suggest the potential for manufacturing ultrahigh‐strength bulk nanocrystalline materials not only for Inconel 718 but also for various metallic materials using powder metallurgy. [ABSTRACT FROM AUTHOR]