Search Results (80)

Rechargeable aqueous Zn-MnO₂ batteries are positioned as a highly promising candidate for next-generation energy storage, owing to their compelling combination of economic viability, inherent safety, exceptional capacity (with a theoretical value of ≈308 mAh·g⁻¹), and eco-sustainability. However, this system still faces multiple critical challenges that hinder its practical application, primarily including the ambiguous energy storage reaction mechanism (e.g., unresolved debates on core issues such as ion transport pathways and phase transition kinetics), dendrite growth and side reactions (e.g., the hydrogen evolution reaction and corrosion reaction) on the metallic Zn anode, inadequate intrinsic electrical conductivity of MnO₂ cathodes (≈10⁻⁵ S·cm⁻¹), active material dissolution, and structural collapse. This review begins by systematically summarizing the prevailing theoretical models that describe the energy storage reactions in Zn-Mn batteries, categorizing them into the Zn²⁺ insertion/extraction model, the conversion reaction involving MnO_x dissolution–deposition, and the hybrid mechanism of H⁺/Zn²⁺ co-intercalation. Subsequently, we present a comprehensive discussion on Zn anode protection strategies, such as surface protective layer construction, 3D structure design, and electrolyte additive regulation. Furthermore, we focus on analyzing the performance optimization strategies for MnO₂ cathodes, covering key pathways including metal ion doping (e.g., introduction of heteroions such as Al³⁺ and Ni²⁺), defect engineering (oxygen vacancy/cation vacancy regulation), structural topology optimization (layered/tunnel-type structure design), and composite modification with high-conductivity substrates (e.g., carbon nanotubes and graphene). Therefore, this review aims to establish a theoretical foundation and offer practical guidance for advancing both fundamental research and practical engineering of Zn-manganese oxide secondary batteries. Full article

Rare earth can modify inclusions in non-oriented silicon steel which is harmful to magnetic properties. This study focused on the 3.1% Si non-oriented silicon steel under industrial production conditions. Samples were taken during the stages before and after addition of rare earth ferrosilicon alloy in Ruhrstahl-Heraeus (RH) unit, different pouring time in tundish, and continuous casting slab. This study systematically examined the morphology, composition, and size distribution of inclusions throughout the smelting process of non-oriented silicon steel by scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS), and thermodynamic analysis at liquid steel temperature and thermodynamic analysis of equilibrium solidification. The research results demonstrated that the rare earth treatment ultimately modifies the original Al₂O₃ inclusions in the non-oriented silicon steel into REAlO₃ and RE₂O₂S inclusions, while also aggregating AlN inclusions to form composite inclusions. After rare earth modification, the average size of the inclusions decreases. In the RH treatment process, the inclusions before the addition of rare earth ferrosilicon alloy are mainly AlN and Al₂O₃. After the addition of rare earth ferrosilicon alloy, the inclusions are mainly RES and REAlO₃. In the tundish and continuous casting, the rare earth content decreased, and the rare earth inclusions transform into RE₂O₂S and REAlO₃. For the size of inclusions, after adding rare earth ferrosilicon alloy, the average size of inclusions rapidly decreased from 16.15 μm to 2.65 μm and reach its minimum size 2.16 μm at the end of RH treatment. When the molten steel entered the tundish, the average size of inclusions increased slightly and gradually decreased with the progress of pouring. The average size of inclusions in the slab is 5.79 μm. Phase stability diagram calculation indicates the most stable rare earth inclusion is Ce₂O₂S in molten steel. Thermodynamic calculations indicated that Al₂O₃, Ce₂O₂S, Ce₂S₃, AlN, and MnS precipitate sequentially during the equilibrium solidification process of molten steel. Full article

This study systematically investigates the influence of Zr additions (0–0.24 wt.%) on the microstructure evolution and mechanical properties of Al–4.0Cu–0.5Mg–0.5Zn–0.5Mn–0.4Ag alloys under peak-aged conditions. Alloys were subjected to homogenization (420 °C/8 h + 510 °C/16 h), solution treatment (510 °C/1.5 h), and aging (190 °C/3 h). Microstructural characterization via OM, SEM, EBSD, and TEM revealed that Zr refines grains and enhances recrystallization resistance through coherent Al₃Zr precipitates, which pin grain boundaries and dislocations. However, excessive Zr (0.24 wt.%) induces heterogeneous grain size distribution and significant Schmid factor variations, promoting stress concentration and premature intergranular cracking. Crucially, Al₃Zr particles act as heterogeneous nucleation sites for Ω-phase precipitates, accelerating their nucleation near grain boundaries, refining precipitates, and narrowing precipitate-free zones (PFZs). Mechanical testing demonstrated that the Al–4.0Cu–0.5Mg–0.5Zn–0.5Mn–0.4Ag alloy exhibits optimal properties: peak tensile strength of 368.8 MPa and 79.8% tensile strength retention at 200 °C. These improvements are attributed to synergistic microstructural modifications driven by controlled Zr addition, establishing Al–4.0Cu–0.5Mg–0.5Zn–0.5Mn–0.4Ag–0.16Zr as a promising candidate for high-temperature aerospace applications. Full article

This study investigated the influence of manganese (Mn) on microstructure evolution and property optimization in Al-0.6Mg-0.58Si-0.24Fe-xMn alloys under both as-cast and hot-extruded conditions. The balance mechanisms of Mn in tensile properties and electrical conductivity of Al-Mg-Si alloy were elucidated, achieving synergistic optimization of strength-elongation-conductivity. For non-equilibrium solidified as-cast alloys, JMatPro simulations coupled with Fe-rich phase size statistics reveal an inhibitory effect of Mn on β-Al₅FeSi phase formation. Matthiessen’s rule analysis quantitatively clarifies Mn-induced resistivity variations through solid solution and phase morphology modifications. In hot-extruded alloys, TEM characterization was used to analyze the structure of Al-Fe-Mn-Si quaternary compounds and clarify their combined effects with typical Mg₂Si phases on dislocation and subgrain configurations. The as-cast Al-0.6Mg-0.58Si-0.24Fe-0.18Mn alloy demonstrate comprehensive properties with ultimate tensile strength, elongation and electrical conductivity. The contributions of dislocations, grain boundaries and precipitates to resistivity are relatively minor, so the main source of resistivity in hot-extruded alloys is still Mn. The hot-extruded alloy containing 0.18 wt.% Mn still has better properties, with a tensile strength of 176 MPa, elongation of 24% and conductivity of 48.07 %IACS. Full article

The present study examines the structure, properties and use of complex-alloyed hypereutectic aluminium-silicon alloys, emphasising the control of the morphology of primary silicon via treatment with various modifiers as well as their effects on its shape and distribution. Furthermore, this study reviews the experimental work related to the simultaneous modification of primary and eutectic silicon, which leads to the conclusion that favourable results can be obtained by complex modification treatment involving first- and second-type modifiers. After being cast, the AlSi18Cu3CrMn and AlSi18Cu5Mg non-standardised piston alloys are subjected to T6 heat treatment intended to enhance their mechanical performance, harnessing the full potential of the alloying elements. A microstructural analysis of the shape and distribution of both primary and eutectic silicon crystals following heat treatment was employed to determine their microhardness. Full article

AlMg5Si2Mn alloys are widely used in the field of automotive castings. Since the morphology, size, and distribution of the primary Al dendrite and eutectic Mg₂Si have a decisive influence on the mechanical properties of the alloy, a comprehensive analysis of AlMg5Si2Mn alloys with varying Y contents was conducted using optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The influence of Y on the microstructural evolution and mechanical behavior of the cast hypoeutectic AlMg5Si2Mn alloy was studied. Experimental findings indicate that the addition of Y significantly refines and alters the morphology of both primary Al and eutectic Mg₂Si in AlMg5Si2Mn alloys. Specifically, in the alloy containing 0.45 wt.% Y, the primary Al undergoes a structural transformation from a coarse dendritic morphology to finer ellipsoidal grains, with a minimum secondary dendritic arm spacing (SDAS) of 18.6 ± 1.6 μm. Simultaneously, the eutectic Mg₂Si morphology transitions from a coarse lamellar structure to finer worm-like, coral-like, and fibrous forms, exhibiting a reduced average length and aspect ratio (AR) of 3.1 ± 0.4. Furthermore, the AlMg5Si2Mn alloy leads to significant improvements in mechanical performance, particularly in tensile strength. The measured average ultimate tensile strength, yield strength, and elongation are 243.3 MPa, 199.0 MPa, and 8.5%, respectively, representing increases of 19.16%, 24.6%, and 203.6% compared to the Y-free alloy. The fracture mode of the alloy fracture transitioned from brittle fracture in its unmodified condition to ductile fracture characteristics. Full article

Nowadays, Pt-based catalysts are widely applied in carbon monoxide (CO) removal at room temperature. However, the effects of abundant hydroxyl groups (OH*) on the decomposition of intermediate products and catalyst durability have rarely been studied. In this work, a novel hydroxyl-rich structured mesh-type Pt/Mn/γ-Al₂O₃/Al catalyst using a water vapor treatment (WVT) strategy to generate OH* in situ was developed. Firstly, density functional theory (DFT) calculations indicated that Mn-modification enhanced the adsorption capacity of CO and reduced the work function and the energy barrier of the catalytic reaction. Meanwhile, the water molecule dissociation ability of the Pt catalyst was improved. Secondly, the effects of WVT on the selected catalysts were investigated, and a possible reaction mechanism was proposed. XPS, FTIR, and TG results showed that WVT increased the content of OH*. Moreover, in situ FTIR further indicated that the increase of OH* content could alter the reaction path (from carbonate to formate pathway), thus enhancing the activity and durability of the catalyst. The selected catalyst exhibited excellent durability with 100% conversion within 200 h for 1000 ppm CO at room temperature. Full article

Layered chalcogenides are interesting from the point of view of the formation of two-dimensional magnetic systems for relevant applications in spintronics. High-spin Mn²⁺ or Fe³⁺ cations with five unpaired electrons are promising in the search for compounds with interesting magnetic properties. In this study, a new layered modification of the Mn₂In₂Se₅ compound from the A₂B₂X₅ family (“225”) was synthesized and investigated. A phase transition to the polymorph with primitive trigonal lattice was recorded at a temperature of 711 °C, which was confirmed by simultaneous thermal analysis, X-ray powder diffraction at elevated temperatures, and sample annealing and quenching. The stability of Mn₂In₂Se₅ in air at high temperatures was investigated by thermal gravimetric analysis and powder X-ray diffraction. The new polymorph of Mn₂In₂Se₅ crystallizes in the Mg₂Al₂Se₅ structure type, as revealed by the Rietveld refinement against powder X-ray diffraction data. The crystal structure can be viewed as a close-packing of Se anions, in which indium and manganese cations are enclosed inside tetrahedral and octahedral voids, respectively, according to the A_MnB_InCB_InC_MnA… sequence. Magnetization measurements reveal an antiferromagnetic-like transition at a temperature of 6.3 K. The same magnetic properties are reported in the literature for the low-temperature R-centered trigonal polymorph. An approximation by the modified Curie–Weiss law yields a significant ratio of |θ|/T_N = 28, which indicates strong magnetic frustration. Full article

Surface coatings are essential for enhancing the mechanical and functional properties of materials. Among these, annealed high-entropy alloy (HEA) coatings have gained attention for improving wear resistance and durability. This study comprehensively analyzes HEA-annealed coatings, focusing on their surface roughness and wear behavior. A systematic and thorough approach is employed to examine the impact of annealing on coating characteristics. The research involves depositing Al _0.1–0.5 CoCrCuFeNi and MnCoCrCuFeNi coatings using the cold spray (CS) method, followed by a controlled annealing process. Surface roughness is evaluated through profilometry and microscopy techniques to assess modifications due to annealing. Tribological tests are conducted to investigate the wear performance of the coatings, and the findings are correlated with roughness measurements, offering insights into the relationship between surface texture and wear resistance. Full article

Background/Objectives: Charcot first described ALS in 1869, but the specific mechanisms that mediate the disease pathology are still not clear. Intense research efforts have provided insight into unique neuroanatomical regions, specific neuronal populations and genetic associations for ALS and other neurodegenerative diseases; however, the experimental results also suggest a convergence of these events to common toxic pathways. We propose that common toxic pathways can be therapeutically targeted, and this intervention will be effective in slowing progression and improving patient quality of life. Here, we focus on understanding the role of IL6 trans-signaling in ALS disease processes. Methods: We leveraged unique mouse models of IL6 trans-signaling that we developed that recapitulate the production of active sIL6R in a genotypic and quantitative fashion observed in humans. Given that the SOD1 transgenic mouse is one of the most highly studied and characterized models of ALS, we bred SOD1^G93A mice with IL6R trans-signaling mice to determine how enhanced trans-signaling influenced symptom onset and pathological processes, including neuromuscular junction (NMJ) denervation, glial activation and motoneuron (MN) survival. Results: The results indicate that in animals with enhanced trans-signaling, symptom onset and pathological processes were accelerated, suggesting a role in disease modification. Administration of an IL6R functional blocking antibody failed to alter accelerated symptom onset and disease progression. Conclusions: Future work to investigate the site-specific influence of enhanced IL6 trans-signaling and the tissue-specific bioavailability of potential therapeutics will be necessary to identify targets for precise therapeutic interventions that may limit disease progression in the 60% of ALS patients who inherit the common Il6R Asp³⁵⁸Ala variant. Full article

Due to the advantages of high capacity, low working voltage, and low cost, lithium-rich manganese-based material (LMR) is the most promising cathode material for lithium-ion batteries; however, the poor cycling life, poor rate performance, and low initial Coulombic efficiency severely restrict its practical utility. In this work, the precursor Mn_2/3Ni_1/6Co_1/6CO₃ was obtained by the continuous co-precipitation method, and on this basis, different doping levels of aluminum–magnesium were applied to modify the electrode materials by high-temperature sintering. The first discharge capacity can reach 295.3 mAh·g⁻¹ for the LMR material of Li_1.40(Mn_0.666Ni_0.162Co_0.162Mg_0.005Al_0.005)O₂. The Coulombic efficiency is 83.8%, and the capacity retention rate remains at 84.4% after 300 cycles at a current density of 1 C for the Mg-Al co-doped LMR material, superior to the unmodified sample. The improved electrochemical performance is attributed to the increased oxygen vacancy and enlarged lithium layer spacing after trace magnesium–aluminum co-doping, enhancing the lithium-ion diffusion and effectively mitigating voltage degradation during cycling. Thus, magnesium–aluminum doping modification emerges as a promising method to improve the electrochemical performance of lithium-rich manganese-based cathode materials. Full article

This paper investigates the interrelated effects of thermomechanical treatments and chemical composition on the phase transformation capabilities of thin sheets made from Cu-Al-Mn shape memory alloys. The transformation capacity and transition temperatures were determined using DSC and DMA testing, while composition measurements were performed using SEM/EDX analysis. The results demonstrate that applying hot-rolling treatments to alloys of reduced thickness leads to manganese oxidation and modifications in chemical composition, adversely impacting the phase transformation performance. This effect can be mitigated by the use of cold rolling. Additionally, the presence of phosphorus impurities can create inclusions that bind manganese, preventing it from remaining in the solid solution and further affecting phase transformation capabilities. Full article

This study investigated the effect of adding La–Ce mixed rare earths and Sr on the microstructure and mechanical properties of AlSi10MnMg alloy. The experiment utilized different combinations of modifiers, including single La–Ce rare earths, single Sr, and the combined addition of La–Ce mixed rare earths and Sr. This study compared their effects on grain refinement, the modification of the α-Al phase and eutectic silicon phase, and tensile properties and hardness. The results showed that the combined modification of Sr and mixed rare earth elements significantly refined the grains, optimized the morphology of the α-Al phase and eutectic silicon phase, and improved the overall mechanical properties of the aluminum alloy. Under the combined modification, the addition of 0.02 wt.% Sr and 0.1 wt.% RE (La–Ce mixed rare earths) exhibited the most pronounced refining effect. The secondary dendrite arm spacing (SDAS) was reduced by 59.18%. The eutectic silicon phase transformed from coarse needle-like shapes to fine fibrous or granular forms, with an aspect ratio reduction of 69.39%. Meanwhile, the alloy’s tensile strength and hardness were significantly improved. The tensile strength increased to 240 MPa, achieving an increase of 23.08%; the yield strength increased to 111 MPa, achieving an increase of 18.09%; and the elongation reached 7.3%, achieving an increase of 73.81%. This indicates that the proper addition of Sr and mixed rare earths can significantly optimize the microstructure and enhance the mechanical properties of AlSi10MnMg alloy, providing an effective method for the preparation of high-performance heat-treatment-free aluminum alloys. Full article

This study investigates the impact of varying extrusion ratios on the microstructure and mechanical properties of AlSiCuFeMnYb alloy. Following hot extrusion, significant enhancements are observed in the microstructure of the cast rare earth aluminium alloy. Within the cross-sectional microstructure, the α-Al phase is reduced in size, and its dendritic morphology is eliminated. The morphology of the eutectic Si phase transitions from long strips to short rods, fine fibres, or granular forms. Similarly, the Fe-rich phase changes from a coarse skeletal and flat noodle shape to small strips and short skeletal forms resembling Chinese characters. The CuAl₂ phase evolves from large blocks to smaller blocks and granular forms, while the Yb (Ytterbium)-rich rare earth phase shifts from large blocks to smaller, more uniformly distributed blocks. In the longitudinal section, the structure aligns into strips along the extrusion direction, with the spacing between these strips decreasing as the extrusion ratio increases. At an extrusion ratio of 22.56, the alloy demonstrates superior mechanical properties with a tensile strength of 325.50 MPa, a yield strength of 254.44 MPa, a hardness of 143.90 HV, and an elongation of 15.47%. These represent improvements of 27.8%, 36.5%, 38.9%, and 236.4%, respectively, compared with the as-cast rare earth alloy. In addition, the fracture surface of the extruded rare earth alloy exhibits obvious ductile fracture characteristics. Additionally, the alloy undergoes dynamic recrystallisation and dislocation entanglement during hot extrusion. The emergence of a twinned Si phase and a dynamically precipitated nanoscale CuAl₂ phase are critical for enhancing deformation strengthening, modification strengthening, and dynamic precipitation strengthening of the extruded alloys. Full article

As a recently developed high-strength aluminium alloy used specifically for laser additive manufacturing, AlMgMnSc alloy possesses superior mechanical properties and excellent processability. Extreme high-speed laser deposition (EHLD) is a novel surface-modification technique, which is characterised by high depositing speed, rapid cooling, rate and minimal dilution rate. To offer a new method for surface repairing high-strength aluminium alloys, an AlMgMnSc alloy coating, containing two deposition layers, is prepared on a 6061 aluminium-alloy axle using the EHLD technique. Meanwhile, the microstructure, composition distribution, and microhardness variation of the fabricated coating are studied. The results reveal that the coating is dense and crack-free, which is well-bonded with the substrate. Additionally, layer 1 is mainly composed of large columnar and equiaxed grains, while layer 2 consists of a fully equiaxed grain structure with an average grain size of about 4.5 μm. Moreover, the microhardness of the coating (about 104~118 HV) is similar to the substrate (about 105 HV), proving the feasibility of repairing high-strength aluminium alloys using AlMgMnSc alloy powders through the EHLD technique. Full article