In response to the growing demand for energy efficiency, safety, and lightweight designs in new energy vehicles, this study addresses the challenge of balancing strength and toughness in ultra-high strength steel(UHSS...
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In response to the growing demand for energy efficiency, safety, and lightweight designs in new energy vehicles, this study addresses the challenge of balancing strength and toughness in ultra-high strength steel(UHSS) components produced by hot stamping. An innovative hot stamping process based on a martensite-bainite(M-B) complex-phase microstructure was proposed to enhance the strength and toughness of UHSS. The microstructural evolution of the M-B complexphase during the hot stamping process was investigated using commercial B1800HS steel. With a microstructure consisting of 87.4.% martensite, 8.7% lower bainite, and 3.9% film-like retained austenite by volume fraction, the steel achieved a tensile strength of 1944 MPa, total elongation of 9.66%, and impact energy of 25.8 J. Compared with conventional hot stamping, the strength of the material showed only a slight improvement, whereas elongation and impact energy were enhanced by approximately 53% and 32%, respectively. A quantitative relationship among process parameters, resulting microstructure, and mechanical properties was established. Optimization between strength and toughness was observed when the low bainite volume fraction ranged from 5.06% to 8.73%. The toughening mechanisms are attributed to the refinement of martensite lath bundles(width of 202 nm) facilitated by bainite formation, the increase in high-angle grain boundaries, and the presence of nanoscale retained austenite(width of 80 nm) between the laths. Additionally, the refinement of grains and the formation of nanoscale(Nb, Ti)C precipitates(diameter of 17 nm) further contributed to the overall strength. The developed M-B complexphase process, which involves medium-temperature slow cooling followed by rapid low-temperature quenching, provides an optimal combination of strength and toughness for a wide range of applications.
With the approaching of large-scale retirement of power lithium-ion batteries(LIBs),their urgent handling is required for environmental protection and resource ***,at present,substantial spent power batteries,especial...
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With the approaching of large-scale retirement of power lithium-ion batteries(LIBs),their urgent handling is required for environmental protection and resource ***,at present,substantial spent power batteries,especially for those high recovery value cathode materials,have not been greenly,sustainably,and efficiently *** to the traditional recovery method for cathode materials with high energy consumption and severe secondary pollution,the direct repair regeneration,as a new type of short-process and efficient treatment methods,has attracted widespread ***,it still faces challenges in homogenization repair,electrochemical performance decline,and scaling-up *** promote the direct regeneration technology development of failed NCM materials,herein we deeply discuss the failure mechanism of nickel-cobalt-manganese(NCM)ternary cathode materials,including element loss,Li/Ni mixing,phase transformation,structural defects,oxygen release,and surface degradation and *** on this,the detailed analysis and summary of the direct regeneration method embracing solid-phase sintering,eutectic salt assistance,solvothermal synthesis,sol-gel process,spray drying,and redox mediation are ***,the upcycling strategy for regeneration materials,such as single-crystallization and high-nickelization,structural regulation,ion doping,and surface engineering,are discussed in ***,the challenges faced by the direct regeneration and corresponding countermeasures are pointed ***,this review provides valuable guidance for the efficient and high-value recovery of failed cathode materials.
By replacing hexyl chains in poly(3-hexylthiophene)(P3HT)with 2-propoxyethyls,four poly(3-(2-propoxyethyl)thiophene)(P3POET)homopolymers with comparable polydispersity indexes(PDI)and regioregularities were prepared h...
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By replacing hexyl chains in poly(3-hexylthiophene)(P3HT)with 2-propoxyethyls,four poly(3-(2-propoxyethyl)thiophene)(P3POET)homopolymers with comparable polydispersity indexes(PDI)and regioregularities were prepared herein in addition with step increment of about 7 kDa on numberaverage molecular weight(M_(n))from around 11 to 32 kDa(accordingly denoted as P11k,P18k,P25k,and P32k).When doped in film by FeCl_(3)at the optimized conditions,the maximum power factor(PF_(max))increases greatly from 4.3μW·m^(-1)·K^(-2)for P11k to 8.8μW·m^(-1)·K^(-2)for P18k,and further to 9.7μW·m^(-1)·K^(-2)for P25k,followed by a slight decrease to 9.2μW·m^(-1)·K^(-2)for *** close Seebeck coefficients(S)at PF_(max)are observed in these doped polymer films due to their consistent frontier orbital energy levels and Fermi *** main contribution to this PF_(max)evolution thus comes from the corresponding conductivities(σ).Theσvariation of the doped films can be rationally correlated with their microstructure evolution.
The method to combine thermoelectric(TE)and magnetocaloric(MC)cooling techniques lies in developing a new material that simultaneously possesses a large TE and good MC cooling *** this work,using n-type Bi_(2)Te_(2.7)...
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The method to combine thermoelectric(TE)and magnetocaloric(MC)cooling techniques lies in developing a new material that simultaneously possesses a large TE and good MC cooling *** this work,using n-type Bi_(2)Te_(2.7)Se_(0.3)(BTS)as the TE base material and Gd as the second-phase MC material,Gd/BTS composites were prepared by the spark plasma sintering *** the composites,interfacial reaction between Gd and BTS was identified,resulting in the formation of Gd Te,which has a large impact on the electron concentration through the adjustment of defect *** MC/TE composite containing 2.5 wt%Gd exhibited a ZT value of 0.6 at 300 K,essentially retaining the original TE performance,while all the composites largely maintained the excellent MC performance of *** work provides a potential pathway to achieving high performance in MC/TE composites.
Graphene prepared by non-covalent modification of sulfonated poly(ether-ether-ketone)(SPG)was combined with polyvinylidene fluoride(PVDF)/Al to improve the PVDF/Al thermal conductivity while reducing the effect of the...
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Graphene prepared by non-covalent modification of sulfonated poly(ether-ether-ketone)(SPG)was combined with polyvinylidene fluoride(PVDF)/Al to improve the PVDF/Al thermal conductivity while reducing the effect of the thermal resistance at the graphene-polymer *** regulation rule of SPG with different contents on the energy release of fluorine-containing system was *** the content of SPG is 4%,the peak pressure and rise rate of SPG/PVDF/Al composite powder during ignition reach the maximum of 4845.28 kPa and 8683.58 kPa/*** the content of SPG is 5%,the PVDF/Al composite powder is completely coated by SPG,and the calorific value of the material reachs the maximum of 29.094 kJ/*** the design and micro-control of the composite powder,the calorific value of the material can be effectively improved,but the improvement of the mass release rate still depends on the graphene content and surface modification state.
Two-dimensional(2D)titanium carbide(Ti_(3)C_(2)T_(x))MXene nanosheets show promising mechanical and electrical properties,indicating great potential applications in aerospace and electronic devices,etc.[1,2].There are...
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Two-dimensional(2D)titanium carbide(Ti_(3)C_(2)T_(x))MXene nanosheets show promising mechanical and electrical properties,indicating great potential applications in aerospace and electronic devices,etc.[1,2].There are many assembling approaches including vacuum filtration,blade coating and layer-by-layer[3–5].However,it still remains a great challenge to realize the intrinsic performance of MXene nanosheets into macroscopic film due to low stress transfer efficiency,which usually is indued by the voids and misalignment during the assembling process[6].Thus,it remains a great challenge to assemble MXene nanosheets into high-performance macroscopic MXene films.
Calcite mesocrystals were proposed, and have been widely reported, to form in the presence of polymer additives via oriented assembly of nanoparticles. However, the formation mechanism and the role of polymer additive...
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Calcite mesocrystals were proposed, and have been widely reported, to form in the presence of polymer additives via oriented assembly of nanoparticles. However, the formation mechanism and the role of polymer additives remain elusive. Here, inspired by the biomineralization process of sea urchin spine comprising magnesium calcite mesocrystals, we show that calcite mesocrystals could also be obtained via atachment of amorphous calcium carbonate(ACC) nanoparticles in the presence of inorganic zinc ***, we demonstrate that zinc ions can induce the formation of temporarily stabilized amorphous nanoparticles of less than 20 nm at a significantly lower calcium carbonate concentration as compared to pure solution, which is energetically beneficial for the atachment and occlusion during calcite growth. The cation-mediated particle atachment crystallization significantly improves our understanding of mesocrystal formation mechanisms in biomineralization and offers new opportunities to bioprocess inspired inorganic ions regulated materials fabrication.
Scar-free wound healing is a challenging process due to the excessive deposition of extracellular matrix and *** overcome this issue,hydrogels with superior biochemical and mechanical properties have been used in comb...
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Scar-free wound healing is a challenging process due to the excessive deposition of extracellular matrix and *** overcome this issue,hydrogels with superior biochemical and mechanical properties have been used in combination with medicinal compounds as wound *** this study,a novel composite hydrogel consisting of double-crosslinked photocurable hyaluronic acid methacrylate(HAMA)and Laponite(Lap)loaded with bioactive bone morphogenetic protein 4(BMP4)was developed and thoroughly characterized for its properties such as degradation,morphology,porosity,compression,skin adhesion and load *** effect of the HAMA/Lap/BMP4 hydrogel was evaluated through both in vitro and in vivo *** the in vivo rabbit ear-scar model,the HAMA/Lap/BMP4 hydrogel dressing was found to reduce scar-related expressions ofα-SAM and decrease the ratio of collagenΙ/III in wounded ***,histopathological examination indicated that the HAMA/Lap/BMP4 hydrogel-treated groups exhibited enhanced wound repair and increased levels of collagen maintenance compared to other standard groups,ultimately leading to scarless wound ***,this sustained-release photocurable HAMA/Lap/BMP4 hydrogel offers a therapeutic approach for scar-free wound healing.
The Si_(3)N_(4)/SiC gradient material with a gradient composition structure was prepared by a hot pressing *** sinterability,distribution of residual stress and the effect of residual stress on mechanical properties o...
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The Si_(3)N_(4)/SiC gradient material with a gradient composition structure was prepared by a hot pressing *** sinterability,distribution of residual stress and the effect of residual stress on mechanical properties of Si_(3)N_(4)/SiC gradient materials were *** research results show that,at 1750℃,Si_(3)N_(4)/SiC gradient materials with different ratios can achieve co-sintering,and the overall relative density of the sample reaches 98.5%.Interestingly,the flexural strength of Si_(3)N_(4)/SiC gradient material is related to its loading *** flexural strength of SiC as the loading surface is about 35%higher than that of Si_(3)N_(4)as the loading *** analysis of the residual stress of the material in the gradient structure shows that the gradient stress distribution between the two phases is a vital factor affecting the mechanical properties of the *** the increase of SiC content in the gradient direction,the fracture toughness of each layer of Si_(3)N_(4)/SiC gradient materials gradually *** surface hardness of the pure SiC side is lower than that reported in other literature.
Advances in electrochemical energy storage technologies drive the need for battery safety performance and miniaturization,which calls for the easily processable polymer electrolytes suitable for on-chip microbattery *...
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Advances in electrochemical energy storage technologies drive the need for battery safety performance and miniaturization,which calls for the easily processable polymer electrolytes suitable for on-chip microbattery ***,the low ionic conductivity of polymer electrolytes and poor-patternable capabilities hinder their application in ***,we modified SU-8,as the matrix material,by poly(ethylene oxide)(PEO)with lithium salts to obtain a patternable lithium-ion polymer *** to the highly amorphous state and more Li-ion transport pathways through blending effect and the increase in number of epoxides,the ionic conductivity of achieved sample is increased by an order of magnitude to 2.9×10^(−4) S·cm^(−1) in comparison with the SU-8 sample at 50°*** modified SU-8 exhibits good thermal stability(>150°C),mechanical properties(elastic modulus of 1.52 GPa),as well as an electrochemical window of 4.3 ***-cell and microdevice were fabricated and tested to verify the possibility of the micro-sized on-chip *** of these results demonstrate a promising strategy for the integration of on-chip batteries with microelectronics.
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