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Phase Transformation on Chemically Corroded Surface of a Single-Crystal Superalloy During In-Situ Tension at Elevated Temperatures
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作者 Wang Rui Li Jiarong +2 位作者 Yue Xiaodai Zhao Jinqian Yang Wanpeng 《稀有金属材料与工程》 北大核心 2026年第3期595-601,共7页
In-situ tensile tests were conducted on a chemically corroded third-generation single-crystal superalloy DD9 at 980 and 1100℃.The phase transformation in the surface areas during the tensile process was analyzed usin... In-situ tensile tests were conducted on a chemically corroded third-generation single-crystal superalloy DD9 at 980 and 1100℃.The phase transformation in the surface areas during the tensile process was analyzed using field emission scanning electron microscope,energy dispersive X-ray spectroscope,electron probe X-ray microanalysis,and transmission electron microscope.The phase transformation mechanism on the surface and the influence mechanism were studied through observation and dynamic calculation.During tensile tests at elevated temperatures,chemical corrosion promotes the precipitation of topologically close-packed(tcp)μphase andσphase on the alloy surface.Both the precipitation amount and size of these two phases on the surface at 1100℃are greater than those at 980℃.The precipitation of tcp phase on the alloy surface results in the formation of an influence layer on the surface area,and the distribution characteristics of alloying elements are significantly different from those of the substrate.The depth of the influence layer at 1100℃is greater than that at 980℃.The precipitation of tcp phase prompts the phase transition fromγphase toγ′phase around the tcp phase. 展开更多
关键词 single-crystal superalloy in-situ tension tcp phase phase transformation alloying element
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A standardized dataset of CO-TPD spectra on transitionmetal single-crystal surfaces
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作者 YANG Lin WU Jianghong WANG He 《燃料化学学报(中英文)》 北大核心 2026年第4期180-190,共11页
Temperature-programmed desorption(TPD)is a fundamental technique in surface science and heterogeneous catalysis for characterizing adsorption behavior,and for extracting key parameters such as adsorption energy.Howeve... Temperature-programmed desorption(TPD)is a fundamental technique in surface science and heterogeneous catalysis for characterizing adsorption behavior,and for extracting key parameters such as adsorption energy.However,the majority of existing TPD data is accessible in the form of published images,which lacks structured and quantitative datasets.This constrains its utility for rigorous quantitative analysis and computational modelling.Using carbon monoxide(CO)which is a widely adopted probe molecule,a curated and standardized dataset of CO-TPD is constructed,encompassing 14 transition-metal single-crystal surfaces,including copper(Cu)and ruthenium(Ru).By systematically extracting numerical data points from published spectra and applying normalization,essential spectral features such as peak shape are fully preserved.The dataset also documents relevant experimental parameters,including heating rates,and was developed using a standardized protocol for data collection and quality control.This resource serves as both a reference library to support the deconvolution of TPD spectra from complex catalysts and an experimental benchmark for calibrating parameters in theoretical models.By providing a reliable and accessible data function,this work advances the microscopic understanding and the rational design of catalyst active centers. 展开更多
关键词 CO-TPD standardized dataset transition metal single-crystal surfaces
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Monolithic Integration of Redox-Stable Sn-Pb Halide Perovskite Single-Crystalline Films for Durable Near-Infrared Photodetection
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作者 Rajendra Kumar Gunasekaran Jihoon Nam +9 位作者 Myeong-geun Choi Won Chang Choi Sunwoo Kim Doyun Im Yeonghun Yun Yun Hwa Hong Sang Hyeok Ryou Hyungwoo Lee Kwang Heo Sangwook Lee 《Nano-Micro Letters》 2026年第5期1-14,共14页
Tin-lead(Sn-Pb)halide perovskite single crystals combine narrow bandgaps,long carrier diffusion lengths,and low trap densities,positioning them as ideal candidates for near-infrared(NIR)optoelectronics.However,convent... Tin-lead(Sn-Pb)halide perovskite single crystals combine narrow bandgaps,long carrier diffusion lengths,and low trap densities,positioning them as ideal candidates for near-infrared(NIR)optoelectronics.However,conventional growth strategies rely on bulk crystallization at elevated temperatures,leading to uncontrolled nucleation,Sn^(2+)oxidation,and poor compatibility with planar integration.Here,we develop a coordination-engineered crystallization strategy that enables direct,lowtemperature growth of micrometer-thick Sn-Pb single-crystal thin films on device-compatible substrates.By modulating metal-solvent coordination strength using a low-donor number cosolvent system,we delineate a narrow processing window that stabilizes precursor speciation,lowers the nucleation barrier,and guides directional crystal growth under mild thermal conditions(<40℃).The resulting crystal films exhibit smooth morphology,high crystallinity,compositional uniformity,and ultralow trap densities(~3.98×10^(12)cm^(-3)).When integrated into NIR photodetectors,these films deliver high responsivity(0.51 A W^(-1)at 900 nm),specific detectivity up to 3.6×10^(12)Jones,fast response(~188μs),and>25,000 cycles of ambient operational stability.This approach establishes a scalable platform for redox-stable,low-temperature growth of Sn-Pb perovskite crystal films and expands the processing-structure-function landscape for next-generation infrared optoelectronics. 展开更多
关键词 Tin-lead perovskite Near-infrared photodetectors single-crystal thin films Coordination chemistry Low-temperature crystallization
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Atomistic Simulation Study on Spall Failure and Damage Evolution in Single-Crystalline Ta at Elevated Temperatures
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作者 Yuntian Wang Taohua Liang +3 位作者 Yuan Zhou Weimei Shi Lijuan Huang Yuzhu Guo 《Computers, Materials & Continua》 2026年第2期355-380,共26页
This investigation utilizes non-equilibrium molecular dynamics(NEMD)simulations to explore shockinduced spallation in single-crystal tantalumacross shock velocities of 0.75–4 km/s and initial temperatures from300 to ... This investigation utilizes non-equilibrium molecular dynamics(NEMD)simulations to explore shockinduced spallation in single-crystal tantalumacross shock velocities of 0.75–4 km/s and initial temperatures from300 to 2000 K.Two spallation modes emerge:classical spallation for shock velocity below 1.5 km/s,with solid-state reversible Body-Centered Cubic(BCC)to Face-Centered Cubic(FCC)orHexagonal Close-Packed(HCP)phase transformations and discrete void nucleation-coalescence;micro-spallation for shock velocity above 3.0 km/s,featuring complete shock-induced melting and fragmentation,with a transitional regime(2.0-2.5 km/s)of partial melting.Spall strength decreases monotonically with temperature due to thermal softening.Elevated temperatures delay void nucleation but increase density,expanding spall regions and enhancing structural disorder with reduced BCC recovery.For microspallation,melting exacerbates damage,causing smaller voids and intensified atomic ejection,which increases with temperature.Free surface velocity profiles indicate damage:in classical spallation,first drop marks nucleation,and pullback signals spall layers.In micro-spallation,the first drop is irrelevant,but remains valid.Temperature delays pullback signals and weakens Hugoniot Elastic Limit.This study clarifies temperature-shock coupling in Ta spallation,aiding failure prediction in high-temperature shock environments. 展开更多
关键词 single-crystal tantalum temperature effect shock-induced spallation damage evolution
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Creep Fracture Behavior and Mechanism of a New Nickel-Based Single-Crystal Superalloy
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作者 Liang Xiangfeng Wu Jili +3 位作者 Kai Xizhou Dai Yong Shi Changkun Zhao Yutao 《稀有金属材料与工程》 北大核心 2025年第11期2795-2801,共7页
A new type of nickel-based single-crystal superalloy was subjected to creep performance test,microstructure observation,and composition analysis under the condition of 1100℃/140 MPa.The variation characteristics of t... A new type of nickel-based single-crystal superalloy was subjected to creep performance test,microstructure observation,and composition analysis under the condition of 1100℃/140 MPa.The variation characteristics of the creep rate during the creep fracture process and the microstructure evolution before and after creep were investigated,thereby revealing the creep fracture mechanism of the new nickel-based single-crystal superalloy.The results indicate that the creep life of the alloy is 104.5 h,and the strain can reach 33.58%.The creep rate decreases first,then increases,and finally tends to be stable until fracture.At the initial stage of creep,the creep rate decreases first,then rises and finally decreases again with time.Furthermore,the creep fracture microstructure is composed of dimples and tearing edges without obvious slip planes.Oxides and recrystallized structures exist inside the fracture surface,and the voids inside the fracture are elongated and perpendicular to the stress axis,showing a fracture mechanism of microcrack accumulation. 展开更多
关键词 nickel-based single-crystal superalloy creep rate fracture characteristics creep mechanisms
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Multiphysics modeling of dendritic thermomechanical deformation during the directional solidification of nickel-based single-crystal superalloys
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作者 Luwei Yang Neng Ren +2 位作者 Mingxu Xia Jun Li Jianguo Li 《International Journal of Minerals,Metallurgy and Materials》 2025年第10期2510-2522,共13页
Nickel-based single-crystal(SX)superalloys are the key metallic materials of aeroengines.However,thermomechanical deformation always occurs during the directional solidification of SX superalloys,negatively influencin... Nickel-based single-crystal(SX)superalloys are the key metallic materials of aeroengines.However,thermomechanical deformation always occurs during the directional solidification of SX superalloys,negatively influencing the SX structure.Casting deformation is simulated in most of the previous studies,whereas the direct simulation of dendritic thermomechanical deformation has been largely ignored,resulting in a lack of comprehensive understanding of this process.In this study,we systematically investigate dendritic thermomechanical deformation with a model coupled with dendrite growth,fluid flow,and thermomechanical deformation behavior.Results reveal that the dendritic thermomechanical deformation-induced dendrite bending is not randomly distributed but is mainly concentrated on the casting surface.The dendritic thermal stress increases as dendrite grows and accumulates after dendrite bridging.Transverse thermal contraction mainly occurs at the edge of casting in the corner,and axial thermal contraction is larger than transverse contraction.The high-stress region of the primary dendrite trunk is mainly distributed below the dendrite bridging near the solidified part,and the stress along the transverse direction reaches its maximum value on the casting surface.Stress concentrated on the casting surface is mainly attributed to variations in transverse temperature gradients caused by heat dissipation on the lateral mold wall,and inconsistent constraints in the lateral mold walls. 展开更多
关键词 dendrite growth thermal stress dendrite deformation single-crystal superalloy SOLIDIFICATION
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High-cycle fatigue life improvement of a PtAl-coated third-generation Ni-based single-crystal superalloy after thermal exposure
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作者 Dong Sun Siliang He +4 位作者 Longfei Li Song Lu Weiwei Zheng Jonathan Cormier Qiang Feng 《International Journal of Minerals,Metallurgy and Materials》 2025年第9期2200-2210,共11页
The as-deposited coating-substrate microstructure has been identified to substantially influence the high-cycle fatigue(HCF)behavior of Ni-based single-crystal(SX)superalloys at 900℃,but the impact of degraded micros... The as-deposited coating-substrate microstructure has been identified to substantially influence the high-cycle fatigue(HCF)behavior of Ni-based single-crystal(SX)superalloys at 900℃,but the impact of degraded microstructure on the HCF behavior remains unclear.In this work,a PtAl-coated third-generation SX superalloy with sheet specimen was thermal-exposed at 1100℃ with different durations and then subjected to HCF tests at 900℃.The influence of microstructural degradation on the HCF life and crack initiation were clarified by analyzing the development of microcracks and coating-substrate microstructure.Notably,the HCF life of the thermal-exposed coated alloy increased abnormally,which was attributed to the transformation of the fatigue crack initiation site from surface mi-crocracks to internal micropores compared to the as-deposited coated alloy.Although the nucleation and growth of surface microcracks occurred along the grain boundaries in the coating and the interdiffusion zone(IDZ)for both the as-deposited and the thermal-exposed coated alloys,remarkable differences of the microcrack growth into the substrate adjacent to the IDZ were observed,changing the crack initiation site.Specifically,the surface microcracks grew into the substrate through the cracking of the non-protective oxide layers in the as-deposited coated alloy.In comparison,the hinderance of the surface microcracks growth was found in the thermal-exposed coated al-loy,due to the formation of a protective Al_(2)O_(3) layer within the microcrack and theγ′rafting in the substrate close to the IDZ.This study will aid in improving the HCF life prediction model for the coated SX superalloys. 展开更多
关键词 platinum-aluminide coating single-crystal superalloy high-cycle fatigue INTERDIFFUSION surface microcracks coating-substrate microstructure
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Construction of a diverting polyoxotungstate based on 3d-5p heterometallic cluster for high-performance single-crystal proton conduction
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作者 Yi Chen Hua-Pan Wu +3 位作者 Zheng-Wei Guo Xin-Xiong Li Ping-Wei Cai Shou-Tian Zheng 《Chinese Chemical Letters》 2025年第11期514-517,共4页
Exploring the synthesis of novel structures is crucial for the development of functional materials.In this context,a novel and intriguing 3d-5p heterometallic cluster-substituted polyoxotungstate material,H_(29)Na_(9)... Exploring the synthesis of novel structures is crucial for the development of functional materials.In this context,a novel and intriguing 3d-5p heterometallic cluster-substituted polyoxotungstate material,H_(29)Na_(9)(H_(2)O)_(21){Ca(H_(2)O)_(2)@Sb_(12)O_(18)[Ni_(2)(OH)(A-α-Si W_(10)O_(37))]_(3)}_(2)·40H_(2)O(1),was constructed using Keggintype polyoxotungstate A-α-Si W_(10)O_(37),along with Ni and Sb elements.The structure features a Tdsymmetric Sb_(12)O_(18)({Sb_(12)})cage that encapsulates an 8-coordinate Ca^(2+)ion at its face.Additionally,the{Sb_(12)}cage forms an 18-nuclear 3d-5p heterometallic cluster by connecting with three di-nuclear nickel clusters through shared oxygen atoms.Electrochemical impedance spectra studies reveal that the single crystal of 1 achieves a proton conductivity of 1.11×10^(-1)S/cm along the[110]direction and 1.04×10^(-1)S/cm along the[100]direction at 85℃ and 98%relative humidity(RH).Furthermore,the powder form of 1 exhibits a proton conductivity of 3.00×10^(-2)S/cm.These findings suggest that compound 1 holds promise as a practical proton conducting material. 展开更多
关键词 POLYOXOTUNGSTATE 3d-5p Heterometallic cluster single-crystAL Proton conduction
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Effects of hot isostatic pressing on the micron-scale residual stress of nickel-based single-crystal superalloys
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作者 Haoyi Niu Zhuangzhuang Liu +3 位作者 Hao Wang Hao Wu Qing Liu Guohua Fan 《Journal of Materials Science & Technology》 2025年第18期102-116,共15页
Quantifying the residual stress at micron-scale is crucial for comprehending the trans-and inter-granular deformation mechanisms and the influence of heat treatment,but remains technically challenging.This study utili... Quantifying the residual stress at micron-scale is crucial for comprehending the trans-and inter-granular deformation mechanisms and the influence of heat treatment,but remains technically challenging.This study utilized focused ion beam and digital image correlation(FIB-DIC)techniques to assess residual stress within the dendrite stem and arm of nickel-based single-crystal superalloys.The influence of hot isostatic pressing(HIP)on the microstructure and residual stress was also elucidated.Our results revealed that the residual stresses in the dendrite stem and arm regions manifest as tensile stress along the x-axis and compressive stress along the y-axis,with a range of−720 MPa to 680 MPa.HIP treatment effectively improved microstructure and regulated residual stress in nickel-based single-crystal superalloys,leading to a rapid reduction in residual stress levels.The present study lays a solid theoretical groundwork for optimizing processing strategies to regulate residual stress and enhance mechanical properties in next-generation single-crystal superalloys. 展开更多
关键词 Nickel-based single-crystal superalloys DENDRITE FIB-DIC Residual stress
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Enabling superior performance in brick-like single-crystal LiMn_(2)O_(4) via BaO flux
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作者 Yuming Shu Hanghang Lei +12 位作者 Jiangnan Huang Qing Pan Baichao Zhang Yixin Xu Ye Zhou Guorong Hu Yanbing Cao Guoqiang Zou Wentao Deng Zhongdong Peng Hongshuai Hou Di Chen Xiaobo Ji 《Chinese Chemical Letters》 2025年第9期672-677,共6页
Conventional polycrystalline LiMn_(2)O_(4)(PC-LMO)suffers from poor Li^(+)diffusion rates and structural instability,negatively affecting its electrochemical performance.Here,we design a single-crystal LMO cathode mat... Conventional polycrystalline LiMn_(2)O_(4)(PC-LMO)suffers from poor Li^(+)diffusion rates and structural instability,negatively affecting its electrochemical performance.Here,we design a single-crystal LMO cathode material using BaO flux(SC-LMOB)to address these issues.The BaO flux enables the fabrication of brick-like single-crystal particles,enhancing Li^(+)diffusion by shortening the diffusion path and increasing the unit cell volume.This process also reduces the specific surface area and stabilizes the crystal structure,effectively mitigating Mn dissolution and polarization.As a result,SC-LMOB exhibits ultra-high rate performance and superior structural stability,retaining 88.8%of its capacity at a 20 C discharge rate and achieving capacity retentions of 85.3%and 86.0%after 500 and 300 cycles at 1 C at room and elevated temperatures,respectively.This structural design offers a low-cost,scalable approach for fabricating single-crystal cathode materials with excellent performance. 展开更多
关键词 single-crystAL FLUX LiMn_(2)O_(4) Stability Lithium-ion battery
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Facile synthesis of single-crystal 3D covalent organic frameworks as stationary phases for high-performance liquid chromatographic separation
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作者 Qiuting Zhang Fan Wu +3 位作者 Jin Liu Hang Su Yanhui Zhong Zian Lin 《Chinese Chemical Letters》 2025年第8期596-600,共5页
Covalent organic frameworks(COFs)have demonstrated great potential in chromatographic separation because of unique structure and superior performance.Herein,single-crystal three-dimensional(3D)COFs with regular morpho... Covalent organic frameworks(COFs)have demonstrated great potential in chromatographic separation because of unique structure and superior performance.Herein,single-crystal three-dimensional(3D)COFs with regular morphology,good monodispersity and high specific surface area,were used as a stationary phase for high-performance liquid chromatography(HPLC).The single-crystal 3D COFs packed column not only exhibits high efficiency in separating hydrophobic molecules involving substituted benzenes,halogenated benzenes,halogenated nitrobenzenes,aromatic amines,aromatic hydrocarbons(PAHs)and phthalate esters(PAEs),but also achieves baseline separation of acenaphthene and acenaphthylene with similar physical and chemical properties as well as environmental pollutants,which cannot be quickly separated on commercial C18 column and a polycrystalline 3D COFs packed column.Especially,the column efficiency of 17303-24255 plates/m was obtained for PAEs,and the resolution values for acenaphthene and acenaphthylene,and carbamazepine(CBZ)and carbamazepine-10,11-epoxide(CBZEP)were 1.7and 2.2,respectively.This successful application not only confirmed the great potential of the singlecrystal 3D COFs in HPLC separation of the organic molecules,but also facilitates the application of COFs in separation science. 展开更多
关键词 single-crystal 3D covalent organic frameworks High-performance liquid chromatography Stationary phase SEPARATION
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New insights into the creep degradation mechanisms in thermal barrier coating/single-crystal superalloy system with temperature and stress dependency
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作者 Hao Su Luqing Cui +7 位作者 Zhenyang Cao Xiaofeng Dang Liyin Zhang Jinguo Li Sihai Luo Qihu Wang Weifeng He Xiaoqing Liang 《Journal of Materials Science & Technology》 2025年第25期75-91,共17页
Thermal barrier coating(TBC)is crucial for the performance of turbine blades at high temperatures;however,it degrades the microstructure of single-crystal superalloy(SX),thereby reducing creep life.Despite this,the de... Thermal barrier coating(TBC)is crucial for the performance of turbine blades at high temperatures;however,it degrades the microstructure of single-crystal superalloy(SX),thereby reducing creep life.Despite this,the degradation mechanisms associated with the complex multi-layer damage and inter-layer diffusion behavior for TBC/SX systems have not yet been fully elucidated.In this study,using integrated experimental efforts and multiscale characterization techniques,the creep degradation mechanisms of TBC/SX systems at 900℃/500 MPa,980℃/300 MPa,and 1050℃/160 MPa are systematically investigated.Results demonstrate that the creep degradation from TBC intensifies with increasing temperature(T)and stress(σ)ratio(T/σ),exhibiting significant dependency on these two factors,and primarily reduces lifespan of the steady-state stage,with minimal effects on the accelerating stage.During creep deformation,the cracking behavior caused by thermally grown oxide(TGO)beneath the top coat(TC)layer,voids resulting from internal oxidation and interdiffusion in the bond coat(BC)layer,and the recrystallization growth driven by the sandblasting process in the secondary reaction zone(SRZ)are temperature-sensitive damages.In contrast,the initiation and propagation of cracks associated with the topologically close-packed(TCP)phases in the SRZ exhibit pronounced stress sensitivity.Furthermore,the formation of the substrate diffusion zone(SDZ)and the decomposition ofγ/γ′interfacial dislocation networks driven by the Cr-Ru diffusion,as well as the increased stacking fault energy in theγ′phase due to Co loss,are responsible for the acceleration of steady-state creep rate at 1050℃/160 MPa.This work provides a comprehensive and in-depth understanding of the degradation mechanisms under thermal-mechanical coupling in TBC/SX systems,offering new insights into targeted design optimization for multilayered coatings. 展开更多
关键词 Nickel-based single-crystal superalloy Thermal barrier coating(TBC) Creep degeneration mechanisms Temperature and stress dependence
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Effect of crystal orientation on tensile mechanical properties of single-crystal tungsten nanowire 被引量:4
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作者 马彬 饶秋华 贺跃辉 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第9期2904-2910,共7页
Based on the high-purity single-crystal tungsten nanowire firstly prepared by the metal-catalyzed vapor-phase reaction method, molecular dynamics method was used to calculate tensile stress-strain curves and simulate ... Based on the high-purity single-crystal tungsten nanowire firstly prepared by the metal-catalyzed vapor-phase reaction method, molecular dynamics method was used to calculate tensile stress-strain curves and simulate microscopic deformation structures of the single-crystal tungsten nanowires with different crystal orientations of 〈100〉, 〈110〉and 〈111〉, in order to reveal the effect of crystal orientation on their tensile mechanical properties and failure mechanisms. Research results show that all of the stress-strain curves are classified into four stages: elastic stage, damage stage, yielding stage and failure stage, where 〈100〉orientation has a special hardening stage after yielding and two descending stages. The crystal orientation has little effect on elastic modulus but great effect on tensile strength, yielding strength and ductility, depending on different atomic surface energies and principal sliding planes. The calculated values of elastic modulus are in good agreement with the tested values of elastic modulus. 展开更多
关键词 crystal orientation stress-strain curve failure mechanism molecular dynamics single-crystal tungsten nanowire
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Dynamic recrystallization of single-crystal nickel-based superalloy 被引量:2
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作者 张兵 刘昌奎 +1 位作者 周静怡 陶春虎 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第6期1744-1749,共6页
The dynamic recrystallization behavior of single-crystal(SC) superalloy SR.R99 at low strain rate was investigated by high-temperature creep testing.The results show that dynamic recrystallization may take place aft... The dynamic recrystallization behavior of single-crystal(SC) superalloy SR.R99 at low strain rate was investigated by high-temperature creep testing.The results show that dynamic recrystallization may take place after the uncoated samples have been creep-tested in air at high temperature and low stress for a long time.Both the threshold temperature and strain for the dynamic recrystallization of SC superalloy SRR99 at low strain rate are lower than those for the static recrystallization.Dynamically recrystallized grains with the depth less than 15 μm are only located in the surface γ'-free layers,and the recrystallized grains are well-developed grains without columnar y'precipitates within them.The dynamic recrystallization behavior of SC superalloy SRR99 at low strain rate is mainly related to high-temperature oxidation.Suitable protective coating can effectively prevent the dynamic recrystallization of SC superalloy components in service.In addition,the dynamic recrystallization behavior of SC superalloy SRR99 at high strain rate was also studied by high-temperature compression testing.At high strain rate,a higher temperature and larger strain are needed for the occurrence of dynamic recrystallization than at low strain rate,and the recrystallized grains have cellular structures with an amount of columnar γ' precipitates within them. 展开更多
关键词 single-crystal superalloy dynamic recrystallization CREEP compression
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Revision of the absolute configurations of Pallavicinia diterpenoids and further discovery of their Diels-Alder cycloadducts
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作者 Jiao-Zhen Zhang Cheng-Min Zhang +7 位作者 Yong-Jie Wang Pei-Lin Wu Rui-Feng Liu Ye Li Ming-Zhu Zhu Shuang-Zhi Yuan Ze-Jun Xu Hong-Xiang Lou 《Chinese Chemical Letters》 2026年第1期394-398,共5页
Owing to their intricate molecular frameworks and copious chiral centers,the structural identification and configurational assignment of natural products are challenging tasks.Comprehensive spectral data analysis is c... Owing to their intricate molecular frameworks and copious chiral centers,the structural identification and configurational assignment of natural products are challenging tasks.Comprehensive spectral data analysis is crucial for the confirmation of absolute configurations.Ignoring critical parameters will lead to false structure,which may confuse the total synthesis and drug development.Herein,the configurations of seven heterogeneous Pallavicinia diterpenoids(PDs) isolated from Pallavicinia liverworts are revised using a combination of single-crystal X-ray diffraction and electronic circular dichroism(ECD) calculations.Meanwhile,identification of five unprecedented PD heterodimers PD-dimers A-E(18-22) along with eleven previously undescribed PDs(5-9,13-17,23) obtained by the reinvestigation of the Chinese liverwort Pallavicinia subciliata have resulted in corrections and support the revised conclusions. 展开更多
关键词 REVISION Absolute configurations Pallavicinia diterpenoids LIVERWORT single-crystal X-ray diffraction Electronic circular dichroism calculations
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Dynamic quantitative deformation mapping of slip activities in NBSC superalloy using sampling moiré method
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作者 Xinyun XIE Qinghua WANG Xiaojun YAN 《Chinese Journal of Aeronautics》 2026年第1期301-312,共12页
Quantitative assessment of microscale slip activities and plastic localizations is essential for understanding the complex deformation mechanisms in crystalline materials.However,few experimental studies have been abl... Quantitative assessment of microscale slip activities and plastic localizations is essential for understanding the complex deformation mechanisms in crystalline materials.However,few experimental studies have been able to dynamically measure the deformation fields of rapidly evolving slip activities at the microscale.In this study,we used the Sampling Moire?Method(SMM)to directly measure the dynamic deformation fields of slip activities in Nickel-Based Single-Crystal(NBSC)superalloy under in-situ tensile test,and the strain and displacement fields under the evolving microplastic events with intense slip activities around the notch of the NBSC superalloy specimen were obtained for the first time.The dynamic evolution of slip bands was quantitatively characterized through detailed statistical analysis of strains and displacements under different loads.The locations of the initial appearance of slip traces were successfully predicted by the regions of plasticity localization.The results show that the deformation fields exhibit both high spatial and temporal resolutions,enabling the capture of nanometer-scale displacement fields and visualization of the dynamic fluidity of slip accumulation.This method demonstrates the superiority of the dynamic characterization of the plastic deformation field at the microscale and the promise of its application for characterizing the slip activities of various crystalline metals. 展开更多
关键词 Dynamic deformation measurement Nickel-based single-crystal superalloys Plastic deformation Samplingmoire method Slip bands evolution
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8-inch free-standing GaN substrates grown by hydride vapor phase epitaxy
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作者 Ruihua Zhang Fang Liu +12 位作者 Yao Wu Hongfen Xu Jinmi He Ming Liu Jianhui Wang Kunyang Li Ping Wang Jiejun Wu Tongjun Yu Qi Wang Jingquan Lu Guoyi Zhang Xinqiang Wang 《Journal of Semiconductors》 2026年第2期80-86,共7页
The absence of large-size gallium nitride(GaN) substrates with low dislocation density remains a primary bottleneck for advancing GaN-based devices. Here, we demonstrate the achievement of 8-inch freestanding GaN subs... The absence of large-size gallium nitride(GaN) substrates with low dislocation density remains a primary bottleneck for advancing GaN-based devices. Here, we demonstrate the achievement of 8-inch freestanding GaN substrates grown by hydride vapor phase epitaxy. Critical to this achievement is the improvement in gas-flow uniformity, which ensures exceptional thickness homogeneity and enables the crack-free growth of GaN. After laser lift-off(LLO) separation, the freestanding GaN substrate exhibits superior crystal quality, evidenced by full width at half maximum values of 68 and 54 arcsec for X-ray diffraction rocking curves of(002) and(102) planes, alongside a low dislocation density of 1.6 × 10^(6) cm^(-2). This approach establishes a robust pathway for the production of large-size GaN substrates, which are essential for advancing next-generation power electronics and high-efficiency photonics. 展开更多
关键词 gallium nitride single-crystal substrates large size hydride vapor phase epitaxy
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Synthesis and properties of single-crystal Ni-rich cathode materials in Li-ion batteries 被引量:15
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作者 Shi-jie LU Yang LIU +4 位作者 Zhen-jiang HE Yun-jiao LI Jun-chao ZHENG Jing MAO Ke-hua DAI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第4期1074-1086,共13页
Single-crystal Ni-rich cathode material LiNi0.88Co0.09Al0.03O2(SC) was synthesized by a high-temperature solid-state calcination method. Physicochemical properties of primary and delithiated SC samples were investigat... Single-crystal Ni-rich cathode material LiNi0.88Co0.09Al0.03O2(SC) was synthesized by a high-temperature solid-state calcination method. Physicochemical properties of primary and delithiated SC samples were investigated by X-ray diffractometry, X-ray photoelectron spectroscopy, and transmission electron microscopy. Electrochemical performance was characterized by long-term cycling, cyclic voltammetry, and in-situ impedance spectroscopy. The results indicated that high temperature rendered layered oxides to lose lithium/oxygen in the interior and exterior, and induced cationic disordering. Besides, the solid-phase synthesis process promoted phase transformation for electrode materials, causing the coexisting multi-phase in a single particle. High temperature can foster the growth of single particles, but it caused unstable structure of layered phase. 展开更多
关键词 lithium-ion battery cathode material single-crystAL electrochemical performance phase transformation
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Microstructure and composition evolution of a single-crystal superalloy caused by elements interdiffusion with an overlay NiCrAlY coating on oxidation 被引量:12
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作者 Lanlan Yang Minghui Chen +4 位作者 Jinlong Wang Yanxin Qiao Pingyi Guo Shenglong Zhu Fuhui Wang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2020年第10期49-58,共10页
MCrAlY(M=Ni and/or Co)overlay coating is widely used as a protective coating against high temperature oxidation and corrosion.However,due to its big difference in chemical composition with the underlying superalloy,el... MCrAlY(M=Ni and/or Co)overlay coating is widely used as a protective coating against high temperature oxidation and corrosion.However,due to its big difference in chemical composition with the underlying superalloy,elements interdiffusion occurs inevitably.One of the direct results is the formation of interdiffusion zone(IDZ)and secondary reaction zone(SRZ)with a high density of fine topological closed-packed phases(TCPs),weakening dramatically the mechanical properties of the alloy substrate.It is by now the main problem of modern high-temperature metallic coatings,but there are still hardly any reports studying the formation,growth and transformation of IDZ and SRZ in deep,as well as the precipitation of TCPs.In this work,a typical NiCrAlY coating is deposited by arc ion plating on a single-crystal superalloy N5.Elements interdiffusion between them and its relationship on microstructure were clarified.Cr rather than Al from the coating diffuses into the alloy at high temperatures and segregates immediately beneath their interface,contributing largely to the formation of IDZ.Simultaneously,diffusion of Ni from the deep alloy to IDZ leads to the formation and continuous expansion of SRZ. 展开更多
关键词 single-crystal superalloys NiCrAlY coating High-temperature oxidation Arcion plating Elements interdiffusion MICROSTRUCTURE
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Comparison of α particle detectors based on single-crystal diamond films grown in two types of gas atmospheres by microwave plasma-assisted chemical vapor deposition 被引量:9
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作者 Yan-zhao Guo Jin-long Liu +9 位作者 Jiang-wei Liu Yu-ting Zheng Yun Zhao Xiao-lu Yuan Zi-hao Guo Li-fu Hei Liang-xian Chen Jun-jun Wei Jian-peng Xing Cheng-ming Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2020年第5期703-712,共10页
Chemical vapor deposition(CVD)-grown diamond films have been developed as irradiation-resistant materials to replace or upgrade current detectors for use in extreme radiation environments. However, their sensitivity i... Chemical vapor deposition(CVD)-grown diamond films have been developed as irradiation-resistant materials to replace or upgrade current detectors for use in extreme radiation environments. However, their sensitivity in practical applications has been inhibited by space charge stability issues caused by defects and impurities in pure diamond crystal materials. In this study, two high-quality CVD-grown single-crystal diamond(SCD) detectors with low content of nitrogen impurities were fabricated and characterized. The intrinsic properties of the SCD samples were characterized using Raman spectroscopy, stereomicroscopy, and X-ray diffraction with the rocking curve mode, cathode luminescence(CL), and infrared and ultraviolet-visible-near infrared spectroscopies. After packaging the detectors, the dark current and energy resolution under α particle irradiation were investigated. Dark currents of less than 5 pA at 100 V were obtained after annealing the electrodes, which is comparable with the optimal value previously reported. The detector that uses a diamond film with higher nitrogen content showed poor energy resolution, whereas the detector with more dislocations showed poor charge collection efficiency(CCE). This demonstrates that the nitrogen content in diamond has a significant effect on the energy resolution of detectors, while the dislocations in diamond largely contribute to the poor CCE of detectors. 展开更多
关键词 single-crystAL DIAMOND NITROGEN IMPURITY DETECTOR αparticle
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