Effects of Mn content on the hydrogen-induced amorphization of LaNi3-xMnx(x=0.0,0.1,0.3 and 0.5) hydrogen storage alloys were studied systematically.All the alloys were prepared using a rapid quenching and annealing m...Effects of Mn content on the hydrogen-induced amorphization of LaNi3-xMnx(x=0.0,0.1,0.3 and 0.5) hydrogen storage alloys were studied systematically.All the alloys were prepared using a rapid quenching and annealing method.As the charging time increased,the hydrogen-induced amorphization occurred gradually in all the compounds for the first cycle.During the discharge process,discharge potential plateau was not observed in LaNi3.As Mn content increased,however,structural changes were inhibited partly,and a p...展开更多
Arc melting was utilized in this study to produce Zr_(55)Cu_(30)Ni_5Al_(10) alloys under mixed atmospheres with various ratios of high-purity hydrogen to argon. The influences of hydrogen addition on the solidificatio...Arc melting was utilized in this study to produce Zr_(55)Cu_(30)Ni_5Al_(10) alloys under mixed atmospheres with various ratios of high-purity hydrogen to argon. The influences of hydrogen addition on the solidification structure and glass-forming ability of Zr_(55)Cu_(30)Ni_5Al_(10) alloy were determined by examining microstructures in different parts of the cast ingots. The results showed that different degrees of crystallization structures were obtained in the ascast button ingots after arc melting in high-purity Ar, and the cross-sectional solidification morphology of arcmelted ingots was found to consist of crystals with varying from the bottom up. By contrast, there were completely amorphous structures in the middle and upper areas of the as-cast button ingots fabricated by adding 10% H_2 to the high-purity Ar atmosphere. A clear solidification interface was found between the crystal and glass in the ascast button ingots, which indicates that hydrogen addition can enhance the Zr_(55)Cu_(30)Ni_5Al_(10) alloy's glass-forming ability. The precise mechanism responsible for this was also investigated.展开更多
Phosphorus plays an indispensable role in the food chain,yet phosphorus mineral resources are finite,underscoring the urgency for developing a closed-loop phosphorus economy.Although there have been advances in phosph...Phosphorus plays an indispensable role in the food chain,yet phosphorus mineral resources are finite,underscoring the urgency for developing a closed-loop phosphorus economy.Although there have been advances in phosphorus recovery from various waste materials,modern agriculture still depends on adequate phosphorus supply to support plant growth.In this study,we explored the amorphization of Ox bone using phytic acid(OxPA),and investigated how varying treatment durations influence the resulting structure.Inductively Coupled Plasma(ICP)analysis was employed to quantify phosphate solubilization.Additionally,pot experiments were conducted to assess the phosphate efficiency of Ox-PA in comparison to untreated Ox bone and control group.The results showed that Ox-PA exhibited significantly higher phosphate solubilization(2973 ppm)than untreated counterpart(13 ppm).When used as a fertilizer,Ox-PA markedly enhanced both aboveground and belowground biomass and root development in maize plants.Moreover,it facilitated increased phosphorus uptake by the plants during their early growth stages.These findings indicate that Ox-PA not only holds significant potential for promoting agronomic sustainability but also contributes meaningfully to the establishment of a circular phosphorus economy.展开更多
Hydrogen-induced cracking (HIC) is one of the most complex material problems that hydrogen can diffuse into and interact with microstructure, degrading their mechanical properties. Microstructural modification is an e...Hydrogen-induced cracking (HIC) is one of the most complex material problems that hydrogen can diffuse into and interact with microstructure, degrading their mechanical properties. Microstructural modification is an effective way to enhance the resistance to HIC. The present study focused on the relationship between the retained austenite (RA) and HIC behavior in NiCrMoV/Nb multi-alloying ultra-strength steel. Results demonstrated that the maximum volume fraction of RA of 9.31% was obtained for QL30T specimen. After the deep cryogenic pretreatment, the volume fraction of RA reduced to 8.8%. RA could reduce the effective diffusion coefficient, while deep cryogenic pretreatment increased the susceptibility of the steel to HIC by a maxim of 14.8%. This was mainly due to the transformation of retained austenite into martensite, degrading the mechanical properties under hydrogen-charged condition. In addition, the deep cryogenic pretreatment had a significant effect on the crack initiation and propagation, with the intergranular (IG) fracture becoming the dominant fracture mode where an increase in the number of secondary cracks in the section. The interfaces of RA and matrix, as well as the grain boundaries, were the preferred sites for cracks initiation.展开更多
Pure magnesium is a very promising material in the fields of biomedical and engineering.Obtaining pure magnesium with superior mechanical properties has consistently been a significant challenge in the area of materia...Pure magnesium is a very promising material in the fields of biomedical and engineering.Obtaining pure magnesium with superior mechanical properties has consistently been a significant challenge in the area of materials science.This study focuses on investigating the processing method and strengthening mechanism of pure magnesium by ultra-precision cutting.The research results show that the pure magnesium grains were significantly refined after ultra-precision cutting.The average grain size reduced from∼24μm to nanometers,and the average nano-hardness increased from 1.02 GPa to 2.82 GPa.Amorphous pure magnesium structure and body-centered cubic(BCC)lattice pure magnesium were reported.Molecular dynamics(MD)simulation confirmed that the high shear strain and hydrostatic pressure during ultra-precision cutting was the origin of amorphization and lattice transformation.The amorphous phase and a significant number of long-period stacking-ordered(LPSO)phases inside the pure magnesium were responsible for the high hardness after ultra-precision cutting.展开更多
Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demo...Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demonstrate considerable promise for use in electrocatalytic water splitting applications.Here,the primary amorphization strategies for achieving the 2D TMO/TMHO NMs are comprehensively reviewed,including low-temperature reaction,rapid reaction,exchange/doping effect,ligand modulation,and interfacial energy confinement.By integrating these strategies with various physicochemical synthesis methods,it is feasible to control the amorphization of TMO/TMHO NMs while maintaining the distinctive benefits of their 2D structures.Furthermore,it delves into the structural advantages of amorphous 2D TMO/TMHO NMs in electrocatalytic water splitting,particularly emphasizing recent advancements in enhancing their electrocatalytic performance through interface engineering.The challenges and potential future directions for the precise synthesis and practical application of amorphous 2D TMO/TMHO NMs are also provided.This review aims to establish a theoretical foundation and offer experimental instructions for developing effective and enduring electrocatalysts for water splitting.展开更多
The morbidity rate of primary cardiac tumors(PCTs)is only 0.0138%.[1]Calcified amorphous tumors(CATs)are a particularly rare entity with only a few cases reported in the literature,and account for only 2.47%of PCTs.[2...The morbidity rate of primary cardiac tumors(PCTs)is only 0.0138%.[1]Calcified amorphous tumors(CATs)are a particularly rare entity with only a few cases reported in the literature,and account for only 2.47%of PCTs.[2]CATs can occur at any age and have been identified at various intracardiac locations.The clinical manifestations of patients are related to the location and size of the lesion.展开更多
Recent advances in geoscience have underscored the critical role of abiogenic processes in petroleum formation,especially the formation and polymerization of methane.However,whether a direct carbon-H_(2) reaction can ...Recent advances in geoscience have underscored the critical role of abiogenic processes in petroleum formation,especially the formation and polymerization of methane.However,whether a direct carbon-H_(2) reaction can produce C_(2+)hydrocarbons(e.g.,ethane and propane)beyond methane remains an open question.Here,we demonstrate the direct synthesis of ethane and propane via reactions between amorphous carbon and H_(2) under upper mantle conditions(2-10 GPa and 800-1200℃).A systematic investigation reveals that increasing structural disorder in carbon precursors,from graphite to glassy carbon-Ⅱ and carbon black,enhances the production of C_(2)-C_(3) hydrocarbons.Through integrated X-ray diffraction and reverse Monte Carlo simulations,we establish that the continuous random atomic network structures in amorphous carbon enable one-step synthesis of heavy hydrocarbons with H_(2).These models establish a direct link between atomic-scale carbon structures and the one-step synthesis of C_(2+) hydrocarbons under H_(2)-rich,high-pressure,and high-temperature conditions—potentially revealing an efficient mechanism for the abiotic production of C_(2+) hydrocarbons in the upper mantle.展开更多
Photoelectrochemical seawater splitting is promising for renewable hydrogen,yet severe chloride corrosion remains a roadblock.Although amorphous catalysts improve hematite(α-Fe_(2)O_(3))photoanode activity,their defe...Photoelectrochemical seawater splitting is promising for renewable hydrogen,yet severe chloride corrosion remains a roadblock.Although amorphous catalysts improve hematite(α-Fe_(2)O_(3))photoanode activity,their defect-enabled functionality inherently accelerates structural degradation,exacerbating chloride-induced corrosion.Here,a synergistic dual-functional nano-armor is designed by anchoring phosphate(PO_(4)^(3-))to active sites on amorphous NiMoO_(4)(a-NiMoO_(4)@PO_(4)^(3-)),achieving dual activitystability enhancement.Detailed physicochemical characterization and density functional theory(DFT)calculations show that the successful and stable anchoring of phosphate is highly dependent on the amorphous structural properties of a-NiMoO_(4).Its rich disordered coordination environment provides sufficient highly reactive sites,allowing PO_(4)^(3-)to be firmly bound through strong coordination bonds,which is the key for the dual role of PO_(4)^(3-)coordination.As a dynamic Cl-shield,PO_(4)^(3-)coordinates unsaturated Ni sites,forming an anionic layer that resists Cl-via steric-electrostatic blocking.As an electronic modulator,PO_(4)^(3-)triggers metal-to-ligand charge transfer at Ni sites,depleting electron density to optimize the intermediate adsorption of oxygen evolution reaction(OER)and reduce kinetic barriers.Simultaneously,this charge redistribution induces a built-in electric field that accelerates holeselective transport.Benefiting from these dual effects,the Fe_(2)O_(3)/a-NiMoO_(4)@PO_(4)^(3-)achieves 4 mA cm^(-2)at 1.23 V_(RHE) with exceptional stability in seawater.This work leverages the unique coordination flexibility of amorphous structures to construct a phosphate-coordinated bifunctional nano-armor on hematite photoanodes,which simultaneously enables efficient chloride exclusion and electronic structure optimization.The synergistic mechanism,rooted in strong phosphate anchoring on amorphous carriers,establishes a new design paradigm for photoelectrochemical systems that integrate high activity with extreme environmental stability,providing an efficient pathway toward corrosion-resistant seawater splitting.展开更多
High‐entropy amorphous catalysts(HEACs)integrate multielement synergy with structural disorder,making them promising candidates for water splitting.Their distinctive features—including flexible coordination environm...High‐entropy amorphous catalysts(HEACs)integrate multielement synergy with structural disorder,making them promising candidates for water splitting.Their distinctive features—including flexible coordination environments,tunable electronic structures,abundant unsaturated active sites,and dynamic structural reassembly—collectively enhance electrochemical activity and durability under operating conditions.This review summarizes recent advances in HEACs for hydrogen evolution,oxygen evolution,and overall water splitting,highlighting their disorder-driven advantages over crystalline counterparts.Catalytic performance benchmarks are presented,and mechanistic insights are discussed,focusing on how multimetallic synergy,amorphization effect,and in‐situ reconstruction cooperatively regulate reaction pathways.These insights provide guidance for the rational design of next‐generation amorphous high‐entropy electrocatalysts with improved efficiency and durability.展开更多
Amorphous metal-based catalysts are highly promising for water splitting due to their abundance of unsaturated active sites.Herein,we report a one-step,surfactant-free synthesis of amorphous nickel nanoparticles(NPs)e...Amorphous metal-based catalysts are highly promising for water splitting due to their abundance of unsaturated active sites.Herein,we report a one-step,surfactant-free synthesis of amorphous nickel nanoparticles(NPs)encapsulated in nitrogen-doped carbon shells(A-Ni@NC)via pulsed laser ablation in liquid(PLAL).The synergistic integration of the amorphous Ni core and a defect-rich N-doped carbon shell markedly enhanced the catalytic activities for both the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),with low overpotentials of 182 mV for HER and 288 mV for OER at 10 mA cm^(-2)in 1.0 m KOH.Furthermore,the bifunctional catalyst achieved a current density of 10 mA cm^(-2)at 1.63 V and retained 98.9%of its initial performance after 100 h of operation.The nitrogen-rich carbon shell not only offered abundant active sites and structural protection but also promoted charge transport.Density functional theory(DFT)calculations revealed that N-doping optimized intermediate adsorption energies,while the amorphous Ni core facilitated efficient electron transfer.This green and scalable synthesis strategy provides a promising platform for developing a wide range of transition metal@N-doped carbon hybrid catalysts for sustainable energy conversion applications.展开更多
Amorphous materials represent a promising platform for advancing CO_(2)electrochemical reduction due to their inherently diverse coordination environments.In this study,we demonstrate computationally the superior perf...Amorphous materials represent a promising platform for advancing CO_(2)electrochemical reduction due to their inherently diverse coordination environments.In this study,we demonstrate computationally the superior performance of amorphous CuNi alloys for CO_(2)electrochemical reduction.By integrating machine learning forcefields for efficient structure generation and density functional theory for subsequent structural refinement and property calculations,we reveal the potential of these disordered systems to outperform their crystalline counterparts.Machine learning forcefields can generate a bulk structure containing a mixture of Cu and Ni atoms,resulting in enhanced catalytic performance.Effective screening of the amorphous surfaces is used to identify undercoordinated Cu and Ni sites in the amorphous structure to synergistically promote selective CO production and favor ethanol formation over ethylene via the stabilization of the*COCHO intermediate,resulting in significantly lower Gibbs free energy changes compared to the crystalline counterpart.The varying atomic coordination environments on amorphous surfaces promote both C–C bond formation and subsequent proton-electron transfer,leading to ethanol formation.These findings demonstrate the superior catalytic performance of amorphous CuNi,highlighting its potential for efficient and selective electroreduction of CO_(2).展开更多
Transition metal selenides as sodium-ion hybrid capacitor(SIHC)anodes still suffer from amorphization difficulties and capacity degradation triggered by polyselenide dissolution.Herein,an atomistic amorphous strategy ...Transition metal selenides as sodium-ion hybrid capacitor(SIHC)anodes still suffer from amorphization difficulties and capacity degradation triggered by polyselenide dissolution.Herein,an atomistic amorphous strategy is proposed to construct adjacent Nb-Nb diatomic pairs with Se/O-coordination(Se4-Nb2-O2)in N-doped carbon-confined amorphous selenide clusters(a-Nb-Se/O@NC).Synergistic carbon confinement and hydrothermal oxygenation induce amorphization of Nb–Se bonds,eliminating crystalline rigidity while creating isotropic dual-ion transport channels and high-density active sites enriched with dangling bonds,thereby enhancing structural integrity and Na+storage capacity.The unique Se/O-coordinated Nb-Nb diatomic configuration establishes an electron-delocalized system,where the low electronegativity of Se counterbalances electron withdrawal from coordinated O at Nb centers.These strengthen d-p orbital hybridization,reduce Na+adsorption energy,and optimize charge transfer pathways and reaction kinetics in the amorphous clusters.Electrochemical tests reveal that the a-Nb-Se/O@NC anode delivers a high reversible capacity of 312.57 mAh g^(−1)and exceptional cyclic stability(103%capacity retention)after 5000 cycles at 10.0 A g^(−1).Assembled SIHCs achieve outstanding energy/power densities(207.1 Wh kg^(−1)/18966 W kg^(−1)),surpassing most amorphous and crystalline counterparts.This work provides methodological insights for the design of electrodes in high-power storage devices through atomic modulation and electronic optimization of amorphous selenides.展开更多
The introduction of two-dimensional(2D)perovskite layers on top of three-dimensional(3D)perovskite films enhances the performance and stability of perovskite solar cells(PSCs).However,the electronic effect of the spac...The introduction of two-dimensional(2D)perovskite layers on top of three-dimensional(3D)perovskite films enhances the performance and stability of perovskite solar cells(PSCs).However,the electronic effect of the spacer cation and the quality of the 2D capping layer are critical factors in achieving the required results.In this study,we compared two fluorinated salts:4-(trifluoromethyl)benzamidine hydrochloride(4TF-BA·HCl)and 4-fluorobenzamidine hydrochloride(4F-BA·HCl)to engineer the 3D/2D perovskite films.Surprisingly,4F-BA formed a high-performance 3D/2D heterojunction,while4TF-BA produced an amorphous layer on the perovskite films.Our findings indicate that the balanced intramolecular charge polarization,which leads to effective hydrogen bonding,is more favorable in 4F-BA than in 4TF-BA,promoting the formation of a crystalline 2D perovskite.Nevertheless,4TF-BA managed to improve efficiency to 24%,surpassing the control device,primarily due to the natural passivation capabilities of benzamidine.Interestingly,the devices based on 4F-BA demonstrated an efficiency exceeding 25%with greater longevity under various storage conditions compared to 4TF-BA-based and the control devices.展开更多
In sodium-ion hybrid capacitors(SIHCs),the high-capacity metal selenide anodes are severely limited by structural instability and polyselenide dissolution/shuttle during cycling.This study proposes an innovative strat...In sodium-ion hybrid capacitors(SIHCs),the high-capacity metal selenide anodes are severely limited by structural instability and polyselenide dissolution/shuttle during cycling.This study proposes an innovative strategy utilizing high-electronegativity N(χ=3.04)to modulate local electronic domains and stabilize amorphous Mo–Se coordination(N/Mo-Se).Through self-polymerization and tunable selenization,N-doped carbon(NC)nanospheres encapsulating N-stabilized amorphous Mo-Se clusters(N/Mo-Se@NC)are successfully constructed.Theoretical and experimental analyses reveal that N-optimization effectively reconstructs the electronic distribution of Mo–Se coordination via strong covalent Mo–N bonds.This significantly enhances the covalency of Mo-Se clusters and induces localized electronic domains,thereby substantially suppressing polyselenide dissolution/shuttle during cycling.Concurrently,the amorphous N/Mo-Se clusters provide isotropic ion diffusion pathways,and together with the threedimensional(3D)conductive networks of the NC,they jointly optimize charge transfer kinetics.The N/Mo-Se@NC anode exhibits a high reversible capacity of 328.7 mAh g^(-1)after 5000 cycles,even at 10.0 A g^(-1),with a remarkable capacity retention of 110%.The assembled N/Mo-Se@NC//AC SIHCs achieve high energy/power densities(236.1 Wh kg^(-1)/9990 W kg^(-1)),demonstrating superior comprehensive performance compared to most previously reported anodes.This study,through high-electronegativity atom modulation and amorphization engineering,opens new avenues for designing highly stable and high-rate Na^(+) storage materials.展开更多
Metal hydrides with high hydrogen density provide promising hydrogen storage paths for hydrogen transportation.However,the requirement of highly pure H_(2)for re-hydrogenation limits its wide application.Here,amorphou...Metal hydrides with high hydrogen density provide promising hydrogen storage paths for hydrogen transportation.However,the requirement of highly pure H_(2)for re-hydrogenation limits its wide application.Here,amorphous Al_(2)O_(3)shells(10 nm)were deposited on the surface of highly active hydrogen storage material particles(MgH_(2)-ZrTi)by atomic layer deposition to obtain MgH_(2)-ZrTi@Al_(2)O_(3),which have been demonstrated to be air stable with selective adsorption of H_(2)under a hydrogen atmosphere with different impurities(CH_(4),O_(2),N_(2),and CO_(2)).About 4.79 wt% H_(2)was adsorbed by MgH_(2)-ZrTi@10nmAl_(2)O_(3)at 75℃under 10%CH_(4)+90%H_(2)atmosphere within 3 h with no kinetic or density decay after 5 cycles(~100%capacity retention).Furthermore,about 4 wt%of H_(2)was absorbed by MgH_(2)-ZrTi@10nmAl_(2)O_(3)under 0.1%O_(2)+0.4%N_(2)+99.5%H_(2)and 0.1%CO_(2)+0.4%N_(2)+99.5%H_(2)atmospheres at 100℃within 0.5 h,respectively,demonstrating the selective hydrogen absorption of MgH_(2)-ZrTi@10nmAl_(2)O_(3)in both oxygen-containing and carbon dioxide-containing atmospheres hydrogen atmosphere.The absorption and desorption curves of MgH_(2)-ZrTi@10nmAl_(2)O_(3)with and without absorption in pure hydrogen and then in 21%O_(2)+79%N_(2)for 1 h were found to overlap,further confirming the successful shielding effect of Al_(2)O_(3)shells against O_(2)and N_(2).The MgH_(2)-ZrTi@10nmAl_(2)O_(3)has been demonstrated to be air stable and have excellent selective hydrogen absorption performance under the atmosphere with CH_(4),O_(2),N_(2),and CO_(2).展开更多
Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improv...Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improved mass transfer and stability.Herein,self-supported crystalline/amorphous NiO/Ni(OH)_(2)nanosheet arrays on nickel foam(NF)are fabricated via an in-situ dissolution-deposition hydrothermal growing of Ni(OH)_(2)nanosheets without additional metal sources assisted by a common Lewis base,EDTA,followed by a rapid calcination at 300℃in air.The as-prepared EDTA-NF-12 h exhibits high OER and HER performance under alkaline conditions,requiring 235 mV and 158 mV,respectively,to reach 10 mA cm^(-2),and the decent performance can be maintained for 24 h without obvious degradation.The dual interfaces,i.e.,the dense crystalline/amorphous interfaces within the NiO/Ni(OH)_(2)nanosheet arrays,as well as the intimate interfaces between nanoarrays and NF,both serve as reaction active sites,facilitate electron transfer,and endow the catalyst with high activity and stability.Furthermore,by applying EDTA-Ni^(2+)and other Lewis bases with varying basicities instead of EDTA,the interfaces with the NF substrate are found to promote the formation of crystalline/amorphous interfaces within the nanosheets.This study offers appealing opportunities for tailoring the electrocatalytic performance of self-supported electrodes via dual interface engineering.展开更多
The effects of the Cr3C2 content and wheel speed on the amorphization behavior of the melt-spun SmCo7-x（Cr3C2）x （x=0.10-0.25） alloys were studied systematically by X-ray diffraction analysis （XRD）, differential ...The effects of the Cr3C2 content and wheel speed on the amorphization behavior of the melt-spun SmCo7-x（Cr3C2）x （x=0.10-0.25） alloys were studied systematically by X-ray diffraction analysis （XRD）, differential scanning calorimetry （DSC） and magnetic measurements. The ribbon melt-spun at lower wheel speed （20 m/s） has composite structure composed of mostly SmCo7 and a small amount of Sm2Co17R. The grain size of SmCo7 phase decreases with the increase of Cr3C2 content. With the increase of wheel speed, the XRD peaks become lower and accompanied with a broad increase in backgrounds, indicating a considerable decrease in the grain size of the SmCo7 phase. When the wheel speed increases to 40 m/s, SmCo7-x（Cr3C2）x alloys can be obtained in the amorphous state for 0.15≤x≤0.25 with intrinsic coercive Hci of 0.004-0.007 T. The DSC analysis reveals that SmCo7 phase firstly precipitates from the amorphous matrix at 650 °C, followed by the crystallization of Sm2Co17 phase at 770 °C.展开更多
Electron irradiation effects on phase stability of the E （Al18Cr2Mg3） phase have been investigated by high- angle annular dark-field scanning transmission electron microscopy and high-resolution transmission electro...Electron irradiation effects on phase stability of the E （Al18Cr2Mg3） phase have been investigated by high- angle annular dark-field scanning transmission electron microscopy and high-resolution transmission electron microscopy （HRTEM）. The in situ HRTEM observations show that the Ala8Cr2Mg3 particles with different thickness undergo amorphization and dissolution under 300 keV electron irradiation at 25 ℃. The results indicate that the intermetallic compound Al18Cr2Mg3 is unstable under electron irradiation, and structural changes mainly depend on the thickness of particles. Amorphization in the thick particles is caused by a combination of chemical disordering and an increase in point defect concentration. Dissolution after amorphization in the thin particles is attributed to the diffusion of point defect towards the Al matrix.展开更多
Influence of vanadium and/or niobium additions on delayed fracture behavior in high strength spring steel was studied by hydrogen permeation method and slow strain rate technique （8SRT）, and its mechanism was analyz...Influence of vanadium and/or niobium additions on delayed fracture behavior in high strength spring steel was studied by hydrogen permeation method and slow strain rate technique （8SRT）, and its mechanism was analyzed. The results show that apparent diffusion coefficient of hydrogen in microalloyed spring steels Nb-V-steel and Nb-steel is lower than that in non-microalloyed steel 60Si2MnA. Percentage of strength reduction in SSRT in air after precharged hydrogen of the microalloyed steels is smaller than that of 60Si2MnA. Addition of the microalloys changes the fracture characteristics. Thence, vanadium and/or niobium additions are a very effective and economy means to improve the hydrogen-induced delayed fracture resistance of high strength spring steel.展开更多
文摘Effects of Mn content on the hydrogen-induced amorphization of LaNi3-xMnx(x=0.0,0.1,0.3 and 0.5) hydrogen storage alloys were studied systematically.All the alloys were prepared using a rapid quenching and annealing method.As the charging time increased,the hydrogen-induced amorphization occurred gradually in all the compounds for the first cycle.During the discharge process,discharge potential plateau was not observed in LaNi3.As Mn content increased,however,structural changes were inhibited partly,and a p...
基金supported by the National Natural Science Foundation of China(51401129,51371066)China Postdoctoral Science Foundation(2015M571327)the Educational Commission of Liaoning Province(L2014052,LGD2016018)
文摘Arc melting was utilized in this study to produce Zr_(55)Cu_(30)Ni_5Al_(10) alloys under mixed atmospheres with various ratios of high-purity hydrogen to argon. The influences of hydrogen addition on the solidification structure and glass-forming ability of Zr_(55)Cu_(30)Ni_5Al_(10) alloy were determined by examining microstructures in different parts of the cast ingots. The results showed that different degrees of crystallization structures were obtained in the ascast button ingots after arc melting in high-purity Ar, and the cross-sectional solidification morphology of arcmelted ingots was found to consist of crystals with varying from the bottom up. By contrast, there were completely amorphous structures in the middle and upper areas of the as-cast button ingots fabricated by adding 10% H_2 to the high-purity Ar atmosphere. A clear solidification interface was found between the crystal and glass in the ascast button ingots, which indicates that hydrogen addition can enhance the Zr_(55)Cu_(30)Ni_5Al_(10) alloy's glass-forming ability. The precise mechanism responsible for this was also investigated.
基金supported by the International Partnership Program of Chinese Academy of Sciences[027GJHZ2022033GC]the National Natural Science Foundation of China[22278415 and 52225309]。
文摘Phosphorus plays an indispensable role in the food chain,yet phosphorus mineral resources are finite,underscoring the urgency for developing a closed-loop phosphorus economy.Although there have been advances in phosphorus recovery from various waste materials,modern agriculture still depends on adequate phosphorus supply to support plant growth.In this study,we explored the amorphization of Ox bone using phytic acid(OxPA),and investigated how varying treatment durations influence the resulting structure.Inductively Coupled Plasma(ICP)analysis was employed to quantify phosphate solubilization.Additionally,pot experiments were conducted to assess the phosphate efficiency of Ox-PA in comparison to untreated Ox bone and control group.The results showed that Ox-PA exhibited significantly higher phosphate solubilization(2973 ppm)than untreated counterpart(13 ppm).When used as a fertilizer,Ox-PA markedly enhanced both aboveground and belowground biomass and root development in maize plants.Moreover,it facilitated increased phosphorus uptake by the plants during their early growth stages.These findings indicate that Ox-PA not only holds significant potential for promoting agronomic sustainability but also contributes meaningfully to the establishment of a circular phosphorus economy.
文摘Hydrogen-induced cracking (HIC) is one of the most complex material problems that hydrogen can diffuse into and interact with microstructure, degrading their mechanical properties. Microstructural modification is an effective way to enhance the resistance to HIC. The present study focused on the relationship between the retained austenite (RA) and HIC behavior in NiCrMoV/Nb multi-alloying ultra-strength steel. Results demonstrated that the maximum volume fraction of RA of 9.31% was obtained for QL30T specimen. After the deep cryogenic pretreatment, the volume fraction of RA reduced to 8.8%. RA could reduce the effective diffusion coefficient, while deep cryogenic pretreatment increased the susceptibility of the steel to HIC by a maxim of 14.8%. This was mainly due to the transformation of retained austenite into martensite, degrading the mechanical properties under hydrogen-charged condition. In addition, the deep cryogenic pretreatment had a significant effect on the crack initiation and propagation, with the intergranular (IG) fracture becoming the dominant fracture mode where an increase in the number of secondary cracks in the section. The interfaces of RA and matrix, as well as the grain boundaries, were the preferred sites for cracks initiation.
基金the National Natural Science Foundation of China(Nos.52175430 and 52105478)for their support of this work.
文摘Pure magnesium is a very promising material in the fields of biomedical and engineering.Obtaining pure magnesium with superior mechanical properties has consistently been a significant challenge in the area of materials science.This study focuses on investigating the processing method and strengthening mechanism of pure magnesium by ultra-precision cutting.The research results show that the pure magnesium grains were significantly refined after ultra-precision cutting.The average grain size reduced from∼24μm to nanometers,and the average nano-hardness increased from 1.02 GPa to 2.82 GPa.Amorphous pure magnesium structure and body-centered cubic(BCC)lattice pure magnesium were reported.Molecular dynamics(MD)simulation confirmed that the high shear strain and hydrostatic pressure during ultra-precision cutting was the origin of amorphization and lattice transformation.The amorphous phase and a significant number of long-period stacking-ordered(LPSO)phases inside the pure magnesium were responsible for the high hardness after ultra-precision cutting.
基金supported by the National Key Research and Development Program of China(No.2018YFA0703700)the National Natural Science Foundation of China(No.12034002)the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities,No.FRF-IDRY-23-033)。
文摘Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demonstrate considerable promise for use in electrocatalytic water splitting applications.Here,the primary amorphization strategies for achieving the 2D TMO/TMHO NMs are comprehensively reviewed,including low-temperature reaction,rapid reaction,exchange/doping effect,ligand modulation,and interfacial energy confinement.By integrating these strategies with various physicochemical synthesis methods,it is feasible to control the amorphization of TMO/TMHO NMs while maintaining the distinctive benefits of their 2D structures.Furthermore,it delves into the structural advantages of amorphous 2D TMO/TMHO NMs in electrocatalytic water splitting,particularly emphasizing recent advancements in enhancing their electrocatalytic performance through interface engineering.The challenges and potential future directions for the precise synthesis and practical application of amorphous 2D TMO/TMHO NMs are also provided.This review aims to establish a theoretical foundation and offer experimental instructions for developing effective and enduring electrocatalysts for water splitting.
文摘The morbidity rate of primary cardiac tumors(PCTs)is only 0.0138%.[1]Calcified amorphous tumors(CATs)are a particularly rare entity with only a few cases reported in the literature,and account for only 2.47%of PCTs.[2]CATs can occur at any age and have been identified at various intracardiac locations.The clinical manifestations of patients are related to the location and size of the lesion.
基金mainly supported by the Natural Science Foundation of China (Grant Nos. 52288102, 52090020, and 52372261)the Natural Science Foundation of Hebei Province (Grant No. E202403045)+1 种基金the S&T Program of Hebei (Grant No. 225A1102D)the Ministry of Education Chang Jiang Scholar Professor Program (Grant No. T2022241)
文摘Recent advances in geoscience have underscored the critical role of abiogenic processes in petroleum formation,especially the formation and polymerization of methane.However,whether a direct carbon-H_(2) reaction can produce C_(2+)hydrocarbons(e.g.,ethane and propane)beyond methane remains an open question.Here,we demonstrate the direct synthesis of ethane and propane via reactions between amorphous carbon and H_(2) under upper mantle conditions(2-10 GPa and 800-1200℃).A systematic investigation reveals that increasing structural disorder in carbon precursors,from graphite to glassy carbon-Ⅱ and carbon black,enhances the production of C_(2)-C_(3) hydrocarbons.Through integrated X-ray diffraction and reverse Monte Carlo simulations,we establish that the continuous random atomic network structures in amorphous carbon enable one-step synthesis of heavy hydrocarbons with H_(2).These models establish a direct link between atomic-scale carbon structures and the one-step synthesis of C_(2+) hydrocarbons under H_(2)-rich,high-pressure,and high-temperature conditions—potentially revealing an efficient mechanism for the abiotic production of C_(2+) hydrocarbons in the upper mantle.
基金supported by the Shandong Provincial Natural Science Foundation(No.ZR2022ME052)the National Natural Science Foundation of China(No.22404153)+4 种基金the TaiShan Scholars of Shandong China(No.tsqn202306113 and tsqn202408081)the Excellent Youth Science Fund Project of Shandong China(No.2025HWYQ-032)the China Postdoctoral Science Foundation(No.2024M753044)the Postdoctoral Fellowship Program of CPSF(No.GZB20240693)the Natural Science Foundation of Qingdao(No.24-4-4-zrjj-9-jch)。
文摘Photoelectrochemical seawater splitting is promising for renewable hydrogen,yet severe chloride corrosion remains a roadblock.Although amorphous catalysts improve hematite(α-Fe_(2)O_(3))photoanode activity,their defect-enabled functionality inherently accelerates structural degradation,exacerbating chloride-induced corrosion.Here,a synergistic dual-functional nano-armor is designed by anchoring phosphate(PO_(4)^(3-))to active sites on amorphous NiMoO_(4)(a-NiMoO_(4)@PO_(4)^(3-)),achieving dual activitystability enhancement.Detailed physicochemical characterization and density functional theory(DFT)calculations show that the successful and stable anchoring of phosphate is highly dependent on the amorphous structural properties of a-NiMoO_(4).Its rich disordered coordination environment provides sufficient highly reactive sites,allowing PO_(4)^(3-)to be firmly bound through strong coordination bonds,which is the key for the dual role of PO_(4)^(3-)coordination.As a dynamic Cl-shield,PO_(4)^(3-)coordinates unsaturated Ni sites,forming an anionic layer that resists Cl-via steric-electrostatic blocking.As an electronic modulator,PO_(4)^(3-)triggers metal-to-ligand charge transfer at Ni sites,depleting electron density to optimize the intermediate adsorption of oxygen evolution reaction(OER)and reduce kinetic barriers.Simultaneously,this charge redistribution induces a built-in electric field that accelerates holeselective transport.Benefiting from these dual effects,the Fe_(2)O_(3)/a-NiMoO_(4)@PO_(4)^(3-)achieves 4 mA cm^(-2)at 1.23 V_(RHE) with exceptional stability in seawater.This work leverages the unique coordination flexibility of amorphous structures to construct a phosphate-coordinated bifunctional nano-armor on hematite photoanodes,which simultaneously enables efficient chloride exclusion and electronic structure optimization.The synergistic mechanism,rooted in strong phosphate anchoring on amorphous carriers,establishes a new design paradigm for photoelectrochemical systems that integrate high activity with extreme environmental stability,providing an efficient pathway toward corrosion-resistant seawater splitting.
基金supported by the Australian Research Council(ARC)Projects(DP220101139,DP220101142,and LP240100542).
文摘High‐entropy amorphous catalysts(HEACs)integrate multielement synergy with structural disorder,making them promising candidates for water splitting.Their distinctive features—including flexible coordination environments,tunable electronic structures,abundant unsaturated active sites,and dynamic structural reassembly—collectively enhance electrochemical activity and durability under operating conditions.This review summarizes recent advances in HEACs for hydrogen evolution,oxygen evolution,and overall water splitting,highlighting their disorder-driven advantages over crystalline counterparts.Catalytic performance benchmarks are presented,and mechanistic insights are discussed,focusing on how multimetallic synergy,amorphization effect,and in‐situ reconstruction cooperatively regulate reaction pathways.These insights provide guidance for the rational design of next‐generation amorphous high‐entropy electrocatalysts with improved efficiency and durability.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(NRF-2023R1A2C1005419).
文摘Amorphous metal-based catalysts are highly promising for water splitting due to their abundance of unsaturated active sites.Herein,we report a one-step,surfactant-free synthesis of amorphous nickel nanoparticles(NPs)encapsulated in nitrogen-doped carbon shells(A-Ni@NC)via pulsed laser ablation in liquid(PLAL).The synergistic integration of the amorphous Ni core and a defect-rich N-doped carbon shell markedly enhanced the catalytic activities for both the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),with low overpotentials of 182 mV for HER and 288 mV for OER at 10 mA cm^(-2)in 1.0 m KOH.Furthermore,the bifunctional catalyst achieved a current density of 10 mA cm^(-2)at 1.63 V and retained 98.9%of its initial performance after 100 h of operation.The nitrogen-rich carbon shell not only offered abundant active sites and structural protection but also promoted charge transport.Density functional theory(DFT)calculations revealed that N-doping optimized intermediate adsorption energies,while the amorphous Ni core facilitated efficient electron transfer.This green and scalable synthesis strategy provides a promising platform for developing a wide range of transition metal@N-doped carbon hybrid catalysts for sustainable energy conversion applications.
基金partially funded by EPSRC (EP/T022213/1, EP/W032260/1 and EP/P020194/1) via our membership of the UK’s HEC Materials Chemistry Consortium, which is funded by EPSRC (EP/L000202)part of the “Advancing Solid Interface and Lubricants by First Principles Material Design (SLIDE)” project that has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant agreement No. 865633)
文摘Amorphous materials represent a promising platform for advancing CO_(2)electrochemical reduction due to their inherently diverse coordination environments.In this study,we demonstrate computationally the superior performance of amorphous CuNi alloys for CO_(2)electrochemical reduction.By integrating machine learning forcefields for efficient structure generation and density functional theory for subsequent structural refinement and property calculations,we reveal the potential of these disordered systems to outperform their crystalline counterparts.Machine learning forcefields can generate a bulk structure containing a mixture of Cu and Ni atoms,resulting in enhanced catalytic performance.Effective screening of the amorphous surfaces is used to identify undercoordinated Cu and Ni sites in the amorphous structure to synergistically promote selective CO production and favor ethanol formation over ethylene via the stabilization of the*COCHO intermediate,resulting in significantly lower Gibbs free energy changes compared to the crystalline counterpart.The varying atomic coordination environments on amorphous surfaces promote both C–C bond formation and subsequent proton-electron transfer,leading to ethanol formation.These findings demonstrate the superior catalytic performance of amorphous CuNi,highlighting its potential for efficient and selective electroreduction of CO_(2).
基金supported by the National Natural Science Foundation of China(Grant No.52573299)the Natural Science Foundation of Jiangxi province(No.20242BAB25223,20232BCJ23025,20232BCJ25040,20232BAB214024)the Special Funding Program for Graduate Student Innovation of Jiangxi Province(No.YC2024-S594).
文摘Transition metal selenides as sodium-ion hybrid capacitor(SIHC)anodes still suffer from amorphization difficulties and capacity degradation triggered by polyselenide dissolution.Herein,an atomistic amorphous strategy is proposed to construct adjacent Nb-Nb diatomic pairs with Se/O-coordination(Se4-Nb2-O2)in N-doped carbon-confined amorphous selenide clusters(a-Nb-Se/O@NC).Synergistic carbon confinement and hydrothermal oxygenation induce amorphization of Nb–Se bonds,eliminating crystalline rigidity while creating isotropic dual-ion transport channels and high-density active sites enriched with dangling bonds,thereby enhancing structural integrity and Na+storage capacity.The unique Se/O-coordinated Nb-Nb diatomic configuration establishes an electron-delocalized system,where the low electronegativity of Se counterbalances electron withdrawal from coordinated O at Nb centers.These strengthen d-p orbital hybridization,reduce Na+adsorption energy,and optimize charge transfer pathways and reaction kinetics in the amorphous clusters.Electrochemical tests reveal that the a-Nb-Se/O@NC anode delivers a high reversible capacity of 312.57 mAh g^(−1)and exceptional cyclic stability(103%capacity retention)after 5000 cycles at 10.0 A g^(−1).Assembled SIHCs achieve outstanding energy/power densities(207.1 Wh kg^(−1)/18966 W kg^(−1)),surpassing most amorphous and crystalline counterparts.This work provides methodological insights for the design of electrodes in high-power storage devices through atomic modulation and electronic optimization of amorphous selenides.
基金supported by the National Key Research and Development Programs-Intergovernmental International Cooperation in Science and Technology Innovation Project(Grant No.2022YFE0118400)the Natural Science Foundation of Hunan Province(2023JJ50132)+1 种基金Shenzhen Science and Technology Innovation Committee(Grants Nos.JCYJ20220818100211025,and KCXST20221021111616039)Shenzhen Science and Technology Program(No.20231128110928003)。
文摘The introduction of two-dimensional(2D)perovskite layers on top of three-dimensional(3D)perovskite films enhances the performance and stability of perovskite solar cells(PSCs).However,the electronic effect of the spacer cation and the quality of the 2D capping layer are critical factors in achieving the required results.In this study,we compared two fluorinated salts:4-(trifluoromethyl)benzamidine hydrochloride(4TF-BA·HCl)and 4-fluorobenzamidine hydrochloride(4F-BA·HCl)to engineer the 3D/2D perovskite films.Surprisingly,4F-BA formed a high-performance 3D/2D heterojunction,while4TF-BA produced an amorphous layer on the perovskite films.Our findings indicate that the balanced intramolecular charge polarization,which leads to effective hydrogen bonding,is more favorable in 4F-BA than in 4TF-BA,promoting the formation of a crystalline 2D perovskite.Nevertheless,4TF-BA managed to improve efficiency to 24%,surpassing the control device,primarily due to the natural passivation capabilities of benzamidine.Interestingly,the devices based on 4F-BA demonstrated an efficiency exceeding 25%with greater longevity under various storage conditions compared to 4TF-BA-based and the control devices.
基金supported by the National Natural Science Foundation of China(Grant No.52573299)the Natural Science Foundation of Jiangxi province(Grant Nos.20242BAB25223,20232BCJ23025,20232BCJ25040,and 20232BAB214024)the Special Funding Program for Graduate Student Innovation of Jiangxi Province(No.YC2024-S594)。
文摘In sodium-ion hybrid capacitors(SIHCs),the high-capacity metal selenide anodes are severely limited by structural instability and polyselenide dissolution/shuttle during cycling.This study proposes an innovative strategy utilizing high-electronegativity N(χ=3.04)to modulate local electronic domains and stabilize amorphous Mo–Se coordination(N/Mo-Se).Through self-polymerization and tunable selenization,N-doped carbon(NC)nanospheres encapsulating N-stabilized amorphous Mo-Se clusters(N/Mo-Se@NC)are successfully constructed.Theoretical and experimental analyses reveal that N-optimization effectively reconstructs the electronic distribution of Mo–Se coordination via strong covalent Mo–N bonds.This significantly enhances the covalency of Mo-Se clusters and induces localized electronic domains,thereby substantially suppressing polyselenide dissolution/shuttle during cycling.Concurrently,the amorphous N/Mo-Se clusters provide isotropic ion diffusion pathways,and together with the threedimensional(3D)conductive networks of the NC,they jointly optimize charge transfer kinetics.The N/Mo-Se@NC anode exhibits a high reversible capacity of 328.7 mAh g^(-1)after 5000 cycles,even at 10.0 A g^(-1),with a remarkable capacity retention of 110%.The assembled N/Mo-Se@NC//AC SIHCs achieve high energy/power densities(236.1 Wh kg^(-1)/9990 W kg^(-1)),demonstrating superior comprehensive performance compared to most previously reported anodes.This study,through high-electronegativity atom modulation and amorphization engineering,opens new avenues for designing highly stable and high-rate Na^(+) storage materials.
基金supported by the National Natural Science Foundation of China(22175136)the State Key Laboratory of Electrical Insulation and Power Equipment(EIPE23127)the Fundamental Research Funds for the Central Universities(xtr052024009).
文摘Metal hydrides with high hydrogen density provide promising hydrogen storage paths for hydrogen transportation.However,the requirement of highly pure H_(2)for re-hydrogenation limits its wide application.Here,amorphous Al_(2)O_(3)shells(10 nm)were deposited on the surface of highly active hydrogen storage material particles(MgH_(2)-ZrTi)by atomic layer deposition to obtain MgH_(2)-ZrTi@Al_(2)O_(3),which have been demonstrated to be air stable with selective adsorption of H_(2)under a hydrogen atmosphere with different impurities(CH_(4),O_(2),N_(2),and CO_(2)).About 4.79 wt% H_(2)was adsorbed by MgH_(2)-ZrTi@10nmAl_(2)O_(3)at 75℃under 10%CH_(4)+90%H_(2)atmosphere within 3 h with no kinetic or density decay after 5 cycles(~100%capacity retention).Furthermore,about 4 wt%of H_(2)was absorbed by MgH_(2)-ZrTi@10nmAl_(2)O_(3)under 0.1%O_(2)+0.4%N_(2)+99.5%H_(2)and 0.1%CO_(2)+0.4%N_(2)+99.5%H_(2)atmospheres at 100℃within 0.5 h,respectively,demonstrating the selective hydrogen absorption of MgH_(2)-ZrTi@10nmAl_(2)O_(3)in both oxygen-containing and carbon dioxide-containing atmospheres hydrogen atmosphere.The absorption and desorption curves of MgH_(2)-ZrTi@10nmAl_(2)O_(3)with and without absorption in pure hydrogen and then in 21%O_(2)+79%N_(2)for 1 h were found to overlap,further confirming the successful shielding effect of Al_(2)O_(3)shells against O_(2)and N_(2).The MgH_(2)-ZrTi@10nmAl_(2)O_(3)has been demonstrated to be air stable and have excellent selective hydrogen absorption performance under the atmosphere with CH_(4),O_(2),N_(2),and CO_(2).
基金the foundation of Guangdong Engineering Technology Research Center for Hydrogen Energy and Fuel Cells,the Guangdong Provincial Department of Education Innovation Project(No.2022KQNCX056)the Guangdong Basic and Applied Basic Research Foundation(Nos.2022A1515110354 and 2021A1515110582)。
文摘Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improved mass transfer and stability.Herein,self-supported crystalline/amorphous NiO/Ni(OH)_(2)nanosheet arrays on nickel foam(NF)are fabricated via an in-situ dissolution-deposition hydrothermal growing of Ni(OH)_(2)nanosheets without additional metal sources assisted by a common Lewis base,EDTA,followed by a rapid calcination at 300℃in air.The as-prepared EDTA-NF-12 h exhibits high OER and HER performance under alkaline conditions,requiring 235 mV and 158 mV,respectively,to reach 10 mA cm^(-2),and the decent performance can be maintained for 24 h without obvious degradation.The dual interfaces,i.e.,the dense crystalline/amorphous interfaces within the NiO/Ni(OH)_(2)nanosheet arrays,as well as the intimate interfaces between nanoarrays and NF,both serve as reaction active sites,facilitate electron transfer,and endow the catalyst with high activity and stability.Furthermore,by applying EDTA-Ni^(2+)and other Lewis bases with varying basicities instead of EDTA,the interfaces with the NF substrate are found to promote the formation of crystalline/amorphous interfaces within the nanosheets.This study offers appealing opportunities for tailoring the electrocatalytic performance of self-supported electrodes via dual interface engineering.
基金Project (51104188) supported by the National Natural Science Foundation for Young Scholars of China
文摘The effects of the Cr3C2 content and wheel speed on the amorphization behavior of the melt-spun SmCo7-x（Cr3C2）x （x=0.10-0.25） alloys were studied systematically by X-ray diffraction analysis （XRD）, differential scanning calorimetry （DSC） and magnetic measurements. The ribbon melt-spun at lower wheel speed （20 m/s） has composite structure composed of mostly SmCo7 and a small amount of Sm2Co17R. The grain size of SmCo7 phase decreases with the increase of Cr3C2 content. With the increase of wheel speed, the XRD peaks become lower and accompanied with a broad increase in backgrounds, indicating a considerable decrease in the grain size of the SmCo7 phase. When the wheel speed increases to 40 m/s, SmCo7-x（Cr3C2）x alloys can be obtained in the amorphous state for 0.15≤x≤0.25 with intrinsic coercive Hci of 0.004-0.007 T. The DSC analysis reveals that SmCo7 phase firstly precipitates from the amorphous matrix at 650 °C, followed by the crystallization of Sm2Co17 phase at 770 °C.
基金financially supported by the 111 Project (No. B08040) of ChinaNational Natural Science Foundation of China (No. 51071125)
文摘Electron irradiation effects on phase stability of the E （Al18Cr2Mg3） phase have been investigated by high- angle annular dark-field scanning transmission electron microscopy and high-resolution transmission electron microscopy （HRTEM）. The in situ HRTEM observations show that the Ala8Cr2Mg3 particles with different thickness undergo amorphization and dissolution under 300 keV electron irradiation at 25 ℃. The results indicate that the intermetallic compound Al18Cr2Mg3 is unstable under electron irradiation, and structural changes mainly depend on the thickness of particles. Amorphization in the thick particles is caused by a combination of chemical disordering and an increase in point defect concentration. Dissolution after amorphization in the thin particles is attributed to the diffusion of point defect towards the Al matrix.
基金Item Sponsored by CITIC-CBMM Niobium Steel Research and Development Projects of China(2007RMJS-D031)
文摘Influence of vanadium and/or niobium additions on delayed fracture behavior in high strength spring steel was studied by hydrogen permeation method and slow strain rate technique （8SRT）, and its mechanism was analyzed. The results show that apparent diffusion coefficient of hydrogen in microalloyed spring steels Nb-V-steel and Nb-steel is lower than that in non-microalloyed steel 60Si2MnA. Percentage of strength reduction in SSRT in air after precharged hydrogen of the microalloyed steels is smaller than that of 60Si2MnA. Addition of the microalloys changes the fracture characteristics. Thence, vanadium and/or niobium additions are a very effective and economy means to improve the hydrogen-induced delayed fracture resistance of high strength spring steel.
