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Fatigue crack propagation of 7050 aluminum alloy FSW joints after surface peening

China Welding 2023年第1期32卷 18-26页

作者：金玉花陈永昇马悦铭王希靖郭廷彪 State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals School of Materials Scienceand EngineeringLanzhou University of TechnologyLanzhou 730050China School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China

The surface composite modification of the 7050 aluminum alloy friction stir-welded joints was performed by shot peening(SP)/multiple rotation rolling(MRR)and MRR/SP,and the fatigue performance of the nugget zone(NZ)was *** results demonstrated that the fatigue life of SP/MRR samples is longer than that of MRR/*** the plane 150μm below the *** grains with high angle grain boundary account for 71.5%and 34.3%for MRR/SP and SP/MRR samples,*** crack propagation path of the MRR/SP is transgranular and intergranular,and it is intergranular for the MRR/*** fatigue striations and some voids appeared at the fracture during the stable crack propagation ***,fatigue striations for SP/MRR are with smaller spacing,fewer holes,and smaller size under SP/MRR compared with fatigue fracture of MRR/*** differences in fatigue properties and fracture characteristics of the NZ are related to the microstructure after the two combined surface modifications.

关键词： 7050 aluminum alloy surface compound modification fatigue crack propagation weld nugget zone

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Strength-ductility balance of AZ31 magnesium alloy via accumulated extrusion bonding combined with two-stage artificial cooling Author links open overlay panel

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Journal of Magnesium and Alloys 2023年第5期11卷 1549-1555页

作者： Tingzhuang Han Guangsheng Huang Heng Li Lifei Wang Hua Zhang Fusheng Pan State Key Laboratory of Solidification Processing School of Materials Science&EngineeringNorthwestern Polytechnical UniversityXi'an 710072PR China Shaanxi Key Lab oratory of High-Performance Precision Forming Technology and Equipment Northwestern Polytechnical UniversityXi'an 710072PR China State Key Laboratory of Mechanical Transmission College of Materials Science and EngineeringChongqing UniversityChongqing 400044PR China College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024PR China Institute for Advanced Studies in Precision Materials Yantai UniversityYantai 264005PR China

AZ31 Mg alloy with heterogeneous bimodal grain structure(smaller grain size of 5-20µm and coarser grain size of 100-200µm)was subjected to accumulated extrusion bonding(AEB)at 250℃combined with two-stage artificial cooling in this work,*** water cooling and artificial *** microstructure developed consecutively as a result of discontinuous dynamic recrystallization(DDRX)for the AEBed samples.{10-12}tensile twinning also played an important role for the AEB with local water cooling at the initial extrusion stage in the *** water cooling could further reduce the DRXed grain size to~2.1µm comparing that without water *** the grain growth rate was reduced by artificial cooling out of extrusion *** the combination of two-stage cooling,the fine DRXed grains at sizing band were almost retained with average grain size of~2.3µm after the sheet out of extrusion die,and the unDRXed grains with high residual dislocation density accumulation were also *** tensile tests results indicated that a good strength-ductility balance with a high ultimate tensile strength(319 MPa vs.412 MPa)and fracture elongation(19.9%vs.30.3%)were *** strength enhancement was mainly owing to the grain refinement and local residual plastic strain reserved by the artificial *** excellent ductility originated from fine DRXed microstructure and ED-tilt double peak texture.

关键词： Magnesium alloy Accumulated extrusion bonding Local water cooling Artificial cooling Microstructure Mechanical properties

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Alkynyl copper(Ⅰ) nanoclusters with thermally activated delayed fluorescence as efficient scintillator for X-ray imaging

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Science China Chemistry 2025年

作者： Jun-Jie Fang Zheng Liu Yu Zhang Zhi-Yi Wang Yun-Peng Xie Xing Lu State Key Laboratory of Materials Processing and Die & Mould Technology School of Materials Science and Engineering Huazhong University of Science and Technology Hubei Key Laboratory of Energy Storage and Power Battery School of Mathematics Physics and Optoelectronics Engineering Hubei University of Automotive Technology

Copper（Ⅰ） nanoclusters （NCs）,compared to other commercial scintillators,exhibit ease of synthesis and cost-effectiveness,demonstrating significant potential for application as X-ray ***,synthesizing atomically precise alkynyl copper（Ⅰ） NCs with high luminescence is still ***,eight propeller-shaped Cu9NCs were successfully *** features a unique triangular prismatic Cu6core,which exhibits significant structural differences compared to other copper（Ⅰ） halide *** modifying triphenylphosphine derivatives and halogens,the Cu9NCs exhibited their highest photoluminescence quantum yield （PLQY） of 43%for *** structural elucidation alongside photophysical and computational analyses have unveiled the mechanisms underlying the thermally activated delayed fluorescence （TADF） performance of these Cu9NCs.A white light-emitting diode （LED） fabricated using 2-CF3powder demonstrates a color rendering index （Ra） of ***,the radioluminescence （RL） of 2-CF3was found to demonstrate a scintillating light yield of 4,924photons/MeV and a low detection limit of 1.239μGy/***,the X-ray imaging resolution of 25.4 line pairs/mm was reported for the 2-CF3screen,representing the top resolution achieved so far for organic-inorganic hybrid *** investigation not only represents the first observation of TADF and RL behaviors in alkynyl copper（Ⅰ） NCs but also provides new insights into advancing scintillator design.

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A SiC nanowires/Ba_(0.75)Sr_(0.25)Al_(2)Si_(2)O_(8) ceramic heterojunction for stable electromagnetic absorption under variable-temperature

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Journal of materials Science & technology 2022年第30期125卷 29-37页

作者： Xin Li Xiaoke Lu Minghang Li Jimei Xue Fang Ye Xiaomeng Fan Yongsheng Liu Laifei Cheng Litong Zhang Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China

The application of semiconductor materials was limited as electromagnetic absorption materials,due to the unstable absorption performance caused by the temperature *** this work,a structurally controllable ceramic heterojunction was developed by assembling structural units of SiC nanowires(SiCnws)and Ba_(0.75)Sr_(0.25)Al_(2)Si_(2)O_(8)(BSAS).Benefiting from the optimization of the energy gap and the construction of heterogeneous interfaces,the ceramic heterojunction can achieve stable electromagnetic absorption from room temperature to 600℃,the effective absorption bandwidth is almost *** the minimum reflection loss value reached-63.6 dB at 600℃.Meanwhile,the SiCnws/BSAS ceramic heterojunction shows stable electromagnetic absorption performance in various simulated outdoor environments,including acid rain,seawater,high temperature and water vapor *** result provides a fire-new idea to realize the environmental adaptability of electromagnetic absorption materials and largely broadens its application prospect.

关键词： Ceramic heterojunction Energy gap regulation Polarization effect Stable electromagnetic absorption Variable-temperature Environment adaptability

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Oxidation Behaviors of Different Grades of Ferritic Heat Resistant Steels in High-Temperature Steam and Flue Gas Environments

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Acta Metallurgica Sinica(English Letters) 2022年第7期35卷 1103-1116页

作者： Xiaogang Li Qu Liu Shanlin Li Yu Zhang Zhipeng Cai Kejian Li Jiluan Pan Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China Collaborative Innovation Center of Advanced Nuclear Energy Technology Tsinghua UniversityBeijing 100084China

For steam tubes used in thermal power plant,the inner and outer walls were operated in high-temperature steam and flue gas environments *** this study,structure,microstructure and chemical composition of oxide films on inner and outer walls of exservice low Cr ferritic steel G102 tube and exservice high Cr ferritic steel T91 tube were *** oxide film was composed of outer oxide layer,inner oxide layer and internal oxidation *** outer oxide layer on the original surface of tube had a porous structure containing Fe oxides formed by diffusion and oxidation of *** specially,the outer oxide layer formed in flue gas environment would mix with coal combustion products during the growth *** inner oxide layer below the original surface of tube was made of Fe–Cr *** internal oxidation zone was believed to be the precursor stage of inner oxide *** formation of internal oxidation zone was due to O diffusing along grain boundaries to form *** were Fe–Cr–Si oxides discontinuously distributed along grain boundaries in the internal oxidation zone of G102,while there were Fe–Cr oxides continuously distributed along grain boundaries in that of T91.

关键词： Ferritic heat resistant steels High temperature service Oxide layer Steam Flue gas Oxidation evolution

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理论揭示锂硫电池第二放电平台的主要液固相转换机制

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Science China materials 2024年第8期67卷 2683-2693页

作者：张洪毅薛红涛魏承东孙杰许健汤富领 School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals Lanzhou University of TechnologyLanzhou 730050China

锂硫电池因其高理论能量密度、环境友好和低廉的成本而被认为是前景广阔的新型储能设备,但在放电后半程中缓慢的还原动力学严重阻碍其实际应用.虽然各种先进的正极材料改善了反应动力学,但硫还原反应(SRR)的复杂机理给提高锂硫电池性能... 详细信息

锂硫电池因其高理论能量密度、环境友好和低廉的成本而被认为是前景广阔的新型储能设备,但在放电后半程中缓慢的还原动力学严重阻碍其实际应用.虽然各种先进的正极材料改善了反应动力学,但硫还原反应(SRR)的复杂机理给提高锂硫电池性能设下许多障碍.深入研究其电催化机理是指导阴极材料设计和应用的重要环节.本文将揭示从Li_(2)S_(3);向Li_(2)_(S))(2)/Li_(2)_(S)的转化机制,即揭示从液相多硫化物到固相多硫化物的硫还原反应.以Ti、V、Fe、Co和Ni单原子催化剂为正极催化材料,建立基于密度泛函理论计算的电催化模型.中间产物^(*)LiS、^(*)LiS_(2)被用作预测反应路径、速率决定步骤和过电位的描述因子.这项工作解释了放电后期可溶多硫化物向不溶多硫化物的转化机理,为设计先进的高性能锂硫电池电催化剂提供了指导.

关键词：锂硫电池电催化剂阴极材料储能设备正极材料多硫化物电催化机理密度泛函理论计算

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Effect of Grain Refinement on Microtexture and Mechanical Properties of Inconel 617 Alloy

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稀有金属材料与工程 2024年第12期53卷 3313-3320页

作者： Ji Jinjin Jia Zhi Yang Peiyao Wang Yanjiang Kou Shengzhong School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050China School of Materials Engineering Lanzhou Institute of TechnologyLanzhou 730050China

The microstructure and mechanical properties of Inconel 617 alloy rolled at room temperature with different deformation degrees(20%,50%,70%)were *** grain refinement mechanism and main texture types of Inconel 617 alloy during rolling were analyzed via electron backscatter diffraction and X-ray diffraction,and the microhardness and tensile properties of Inconel 617 alloy with different deformation degrees were *** reveal that the grains of Inconel 617 alloy are refined during the rolling deformation process,and the refinement mechanism is the fragmentation of original grains caused by the increase in dislocation density and strain *** main microtextures of the rolled samples are Goss{011}<001>,Rotated Goss{110}<110>,Brass{011}<211>,and P{011}<112>textures,and their intensity is increased with increase in deformation *** rolling deformation,the strength of the Inconel 617 alloy is improved and the ductility is reduced by the combined effect of grain refinement and dislocation ***,the yield strength and elongation of Inconel 617 alloy after 20%deformation are 772.48 MPa and 0.1962,respectively,presenting good synergy effect.

关键词： Inconel 617 alloy grain refinement microtexture microhardness tensile properties

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BaTiO_(3)/Polyurethane Dielectric Composites with Diels-Alder Bond for Improved Self-Healing Properties

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Journal of Renewable materials 2022年第9期10卷 2355-2364页

作者： unlong Yao Wei Nie Zhengguang Sun Huan Yang Yu Guan Lin Gao Xueliang Jiang Mujie Guo Chuanxi Xiong Hubei Key Laboratory of Plasma Chemistry and Advanced Materials School of Materials Science and EngineeringWuhan Institute of TechnologyWuhan430205China Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials Hubei UniversityWuhan430062China Key Laboratory of Green Chemical Engineering Process of Ministry of Education Wuhan Institute of TechnologyWuhan430205China School of Chemistry and Environmental Engineering Jianghan UniversityWuhan430056China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing and School of Materials Science and EngineeringWuhan University of TechnologyWuhan430070China

In general,self-healing dielectric composites are mainly composed of polar hydrogen bonds,which have high hydrophilicity and are unsuitable for humid *** composite with Diels-Alder(D-A)bond contains covalent bonds,it can be adopted as an efficient self-healing ***,we construct self-healing barium titanate(BT)/polyurethane(PU)dielectric composites by adopting PU with D-A bond as matrix(BT/PU-DA).The prepared 10%BT/PU-DA composite exhibits superior self-healing ability than that of ***,its dielectric constant can reach 9.3 with a loss of only 0.04 at 1000 Hz and maintain 93%repair efficiency of tensile *** experimental analysis suggests the introduction of D-A bond can enhance the thermostability and self-healing ability of BT/PU-DA *** addition,the incorporation of BT nanoparticles and D-A bond in the self-healing composite contributes to the lower dielectric loss and excellent tensile strength after *** adopted strategy is a promising and facile approach to develop highly efficient selfhealing dielectric material,which will be conducive to reuse and sustainable development of the electronic packaging material in aqueous medium or wet environment.

关键词： Diels-Alder bond self-healing dielectric properties tensile strength polyurethane

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Microstructure characteristics and mechanical properties of NbMoTiVWSix refractory high-entropy alloys

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China Foundry 2022年第6期19卷 495-502页

作者： Qin Xu Qi Wang De-zhi Chen Yi-ang Fu Qing-sheng Shi Ya-jun Yin Shu-yan Zhang School of Mechanic and Electrical Engineering Henan University of TechnologyZhengzhou 450001China National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Materials Processing and Die&Mould Technology Huazhong University of Science&TechnologyWuhan 430074China Centre of Excellence for Advanced Materials Songshan LakeDongguan 523808GuangdongChina

Refractory high-entropy alloys are considered as potential structural materials for elevated temperature *** obtain refractory high-entropy alloys with high strength,different amounts of Si were added into the NbMoTiVW refractory high-entropy *** effects of Si on the phase constitution,microstructure characteristics and mechanical properties of NbMoTiVWSi_(x) alloys were *** show that when the addition of Si is 0,0.025 and 0.05(molar ratio),the alloys are consisted of primary BCC and secondary BCC in the intergranular *** the addition of Si is increased to 0.075 and 0.1,eutectic structure including silicide phase and secondary BCC phase is *** primary BCC phase shows dendritic morphology,and is refined by adding *** volume fraction of intergranular area is increased from 12.22%to 18.13%when the addition of Si increases from 0 to *** ultimate compressive strength of the NbMoTiVW alloy is improved from 2,242 MPa to 2,532 *** yield strength is also improved by the addition of Si,and the yield strength of NbMoTiVWSi_(0.1) reaches maximum of 2,298 ***,the fracture strain of the alloy is decreased from 15.31%to 12.02%.The fracture mechanism of the alloys is changed from mixed fracture of ductile and quasi-cleavage to cleavage fracture with increasing of *** strengthening of alloys is attributed to the refinement of primary BCC phase,volume fraction increment of secondary BCC phase,and formation of eutectic structure by addition of Si.

关键词： high-entropy alloy second phase microstructure refinement mechanical property strengthening

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High wave transmittance and low thermal conductivity Y-a-SiAlON porous ceramics for high-temperature radome applications

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Journal of advanced Ceramics 2023年第6期12卷 1273-1287页

作者： Runwu Yang Jie Xu Jia Guo Xuanyu Meng Ping Zhang Fengying Fan Yanan Qu Feng Gao State Key Laboratory of Solidification Processing MIIT Key Laboratory of Radiation Detection Materials and DevicesSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'an 710072China NPU-QMUL Joint Research Institute of Advanced Materials and Structure Northwestern Polytechnical UniversityXi'an 710072China Railway Engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China

With the development of hypersonic vehicle technology,ceramic-based radome materials are highly demanded due to their high operating temperatures,good dielectric properties,and high mechanical ***α-SiAlON is an ideal material for radome applications,its intrinsic low transmittance and high thermal conductivity limit its ***,we prepared Y-α-SiAlON porous ceramics through tert-butanol(TBA)gel-casting using the self-synthesizedα-SiAlON *** Y-α-SiAlON porous ceramics exhibited a uniform micron-level connected pore structure with the porosity(P)of 44.2%-58.6%.The real part of permittivity(s')was 3.13-4.18(8.2-12.4 GHz),which decreased significantly with the increasing *** wave transmittance(|T|^(2))of the sample with porosity of 58.6%could exceed 80%in the thickness range of 6-10 *** thermal conductivity was maintained at a low level of 1.38-2.25 W·m^(-1)·K^(-1) owing to the introduction of the pore *** flexural strength was 44.73-88.33 MPa,which may be increased by rod-likeα-SiAlON *** results indicate that the prepared Y-α-SiAlON porous ceramics meet the requirements of high-temperature wave-transmitting materials for radome applications.

关键词： a-SiAlON porous ceramics wave-transmittance materials thermal conductivity flexural strength

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