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Journal of Materials Science & Technology 2023年第6期137卷 159-175页

作者： Meng Li Zhang-Zhi Shi Qiang Wang Yang Cheng Lu-Ning Wang Beijing Advanced Innovation Center for Materials Genome Engineering School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China

Environmentally degradable Zn-0.8Mn alloy is highly ductile,which lays the foundation for developing high-performance Zn-Mn-based alloys.However,not only constitutive equation of this alloy is unknown,but also its dynamic recrystallization(DRX)behavior is unclear,which makes optimization of hot pro-cessing parameters of this alloy almost dependent on trial-and-error.This work aims to tackle these prob-lems.The constitutive equation was deduced to be˙ε=1.38×10^(12)×[sinh(0.009σ)]^(8)exp(-135150/RT).A processing map of the alloy was obtained for the first time,which shows that it has excellent hot formability with narrow instability zones.At a final true strain of 0.8,the volume fraction of DRX grains increased from 37%to 79%with temperature increasing from 150℃to 350℃and strain rate decreas-ing from 10 s^(−1)to 10^(-3)s^(−1).Discontinuous DRX(DDRX),continuous DRX(CDRX),twinning-induced DRX(TDRX),and particle stimulated nucleation(PSN)were activated during hot compressions.DDRX was al-ways the main mechanism.TDRX was completely suppressed at 300℃and above.PSN arose from dis-persed MnZn 13 particles.Furthermore,Zn-0.8Mn alloy exhibited elevated-temperature strengths better than pure Zn and Zn-Al-based alloys.At 300℃and 0.1 s^(−1),its peak stress was 1.8 times of pure Zn,owing to MnZn 13 particles of 277±79 nm impeding the motion of grain boundaries and dislocations.

关键词： Environmentally degradable Zn-0.8Mn alloy Hot deformation DRX Constitutive equations Microstructure

Crystallography of precipitates in Mg alloys

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Journal of Magnesium and Alloys 2021年第2期9卷 416-431页

作者： Zhang-Zhi Shi Hong-Ting Chen Ke zhang Fu-zhi Dai Xue-Feng Liu Beijing Laboratory of Metallic Materials and Processing for Modern Transportation Key Laboratory for Advanced Materials Processing of Ministry of EducationSchool of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China Science and Technology on Advanced Functional Composite Laboratory Aerospace Research Institute of Materials&Processing TechnologyBeijing 100076China

Crystallography of precipitates in Mg alloys is indispensable to explain and predict alloy microstructures and properties.In order to obtain a global understanding of diversified experimental results,a general theory of singular interface is introduced,which provides the physical base and calculation methodology for interpreting precipitate morphology and orientation relationship(OR),especially useful for understanding irrational facets and ORs.Guided by the theory,recent experimental findings are systematically summarized,including thermally stable and metastable precipitates with various crystal structures.Then,theoretical advances inspired by the findings are introduced,which deepens our understanding on OR selection and preference of irrational facets.At last,future research directions in this field are proposed.

关键词： Mg alloys Precipitation Facet Orientation relationship

Influence of high-temperature oxidation of SiC powders on curing properties of SiC slurry for digital light processing

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Journal of Advanced Ceramics 2023年第1期12卷 169-181页

作者： zhang-Ao shi Jia-Min WU zhi-Qiang FANG Yu-Sheng shi State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China Engineering Research Center of Ceramic Materials for Additive Manufacturing Ministry of EducationWuhan 430074China

Fabrication of silicon carbide(SiC)ceramics by digital light processing(DLP)technology is difficult owing to high refractive index and high ultraviolet(UV)absorptivity of SiC powders.The surface of the SiC powders can be coated with silicon oxide(SiO_(2))with low refractive index and low UV absorptivity via high-temperature oxidation,reducing the loss of UV energy in the DLP process and realizing the DLP preparation of the SiC ceramics.However,it is necessary to explore a high-temperature modification process to obtain a better modification effect of the SiC powders.Therefore,the high-temperature modification behavior of the SiC powders is thoroughly investigated in this paper.The results show that nano-scale oxide film is formed on the surface of the SiC powders by short-time high-temperature oxidation,effectively reducing the UV absorptivity and the surface refractive index(nʹ)of the SiC powders.When the oxidation temperature is 1300℃,compared with that of unoxidized SiC powders,the UV absorptivity of oxidized SiC powders decreases from 0.5065 to 0.4654,and a curing depth of SiC slurry increases from 22±4 to 59±4μm.Finally,SiC green bodies are successfully prepared by the DLP with the the oxidized powders,and flexural strength of SiC sintered parts reaches 47.9±2.3 MPa after 3 h of atmospheric sintering at 2000℃without any sintering aid.

关键词： silicon carbide(SiC)powders oxidation modification digital light processing(DLP) ultraviolet(UV)absorptivity curing depth

A universal probe for simultaneous detection of six pospiviroids and natural infection of potato spindle tuber viroid(PSTVd) in tomato in China

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Journal of Integrative Agriculture 2023年第3期22卷 790-798页

作者： zhang Yu-hong LI zhi-xin DU Ya-jie LI shi-fang zhang zhi-xiang State Key Laboratory for Biology of Plant Diseases and Insect Pests Institute of Plant ProtectionChinese Academy of Agricultural SciencesBeijing 100193P.R.China Keshan Branch of Heilongjiang Academy of Agricultural Sciences Qiqihar 161005P.R.China College of Agronomy and Biotechnology Hebei Normal University of Science&TechnologyQinhuangdao 066004P.R.China

Several viroids in the genus Pospiviroid can infect tomato(Solanum lycopersicum)and cause severe diseases,posing a serious threat to tomato production.For simultaneous detection of six tomato-infecting pospiviroids-columnea latent viroid(CLVd),pepper chat fruit viroid(PCFVd),potato spindle tuber viroid(PSTVd),tomato apical stunt viroid(TASVd),tomato chlorotic dwarf viroid(TCDVd),and tomato planta macho viroid(TPMVd),we developed a universal probe based on a highly conserved 61 nt long sequence shared among them.Compared with their specific probes,the universal probe has a similar,though slightly reduced,detection sensitivity and has the advantages of simple and cost-effective preparation and simultaneous detection of the six pospiviroids.In addition,the universal probe was used in dot-blot hybridization assays for a large-scale survey of viroid(s)in tomato plantings in China.Only PSTVd was detected in a few greenhouse-planted tomato plants.Sequence analysis revealed that these tomato PSTVd isolates may have been introduced from tomato seeds imported from abroad.

关键词： tomato viroid simultaneous detection molecular hybridization pospiviroids

300 MPa grade highly ductile biodegradable Zn-2Cu-(0.2-0.8)Li alloys with novel ternary phases

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Journal of Materials Science & Technology 2023年第26期157卷 234-245页

作者： Meng Cao Zhe Xue Zhao-Yong Lv Jin-Ling Sun Zhang-Zhi Shi Lu-Ning Wang Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advance Metals and MaterialsSchool of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China Orthopedics Department Peking University ShouGang HospitalBeijing 100144China Advanced Technology and Materials Co. Ltd.(AT&M)Beijing 100081China Liaocheng People’s Hospital Liaocheng Hospital Affiliated to Shandong First Medical UniversityLiaocheng 252000China

Although a few high-strength biodegradable Zn alloys with yield strengths(YSs)over 300 MPa in rolled state have been developed,their elongations(ELs)are generally less than 30%.This study developed rolled Zn-2Cu-x Li(x=0.2 wt.%,0.5 wt.%,0.8 wt.%)alloys with YSs of 316-335 MPa and ELs of 44%-61%.Three-dimensional atom probe(3DAP)and time of flight secondary ion mass spectrometry(TOF-SIMS)were employed to characterize Li distribution.Three kinds of Zn-Cu-Li ternary phases are identified,which are blockyε′-(Cu_(0.5),Li_(0.5))Zn 4,blockyβ′-(Li_(0.9),Cu_(0.1))Zn 4,and small roundγparticles with high Li content in the annealed state.Other identified phases are Zn,β-LiZn 4,andε-CuZn 4 phases.With the increase of Li content in the alloys,ε′phase with 6.50 at.%Cu transforms intoβ′phase with 2.12 at.%Cu,i.e.,the average level in the alloys.Withinε′phase,there exist nano-scale Li clusters andεphase,resulting inε′/εstructure.Dense Zn laths precipitate fromβ′phase,resulting inβ′/Zn lamellar structure.The lamel-lar structure is the matrix of Zn-2Cu-0.8Li and leads to near-isotropic plasticity.Electrochemistry tests show that degradation rates fall in the range of 153-196μm/year,which decrease with Li content.All the alloys exert positive effects on the growth of MC3T3-E1 cells with 10%extract.This research reveals how microstructure evolves in Zn-2Cu-x Li alloys,which lays the foundation for their future applications.

关键词： Biodegradable Zn alloys Zn-Cu-Li ternary phase Microstructure

Combined Heat, Air, Moisture and Pollutant Simulations (CHAMPS) research for building and urban energy efficiency and environmental quality analysis

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Building Simulation 2021年第2期14卷 237-239页

作者： zhi Gao Weihui Liang Shanshan shi Jianshun zhang School of Architecture and Urban Planning Nanjing University22 Hankou RoadNanjingJiangsu Province210093China Department of Mechanical and Aerospace Engineering Syracuse University263 Link HallSyracuseNY13244USA

The energy and environmental performance of buildings and communities depends on how the heat,air,moisture and pollutant flows are managed and controlled in the system.Combined Heat,Air,Moisture and Pollutant Simulations(CHAMPS)research and development is vital to the optimal design and operation of building and urban energy and environmental systems.

关键词： Simulation moisture (CH

300 MPa grade biodegradable high-strength ductile low-alloy(BHSDLA)Zn-Mn-Mg alloys:An in vitro study

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Journal of Materials Science & Technology 2023年第7期138卷 233-244页

作者： Zhang-Zhi Shi Xiang-Min Li Sheng-Lian Yao Yun-zhi Tang Xiao-Jing Ji Qiang Wang Xi-Xian Gao Lu-Ning Wang Beijing Advanced Innovation Center for Materials Genome Engineering Key Laboratory for Advanced Materials Processing of Ministry of EducationSchool of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China

300 MPa grade biodegradable Zn-(0.6,0.8)Mn-(300 MPa and elongations>15%have been developed,which are designated as Zn06Mn006Mg(HE)and Zn08Mn005Mg(HE)in as-extruded state.They are the newest members of a small group of biodegradable Zn alloys with mechanical properties beyond the generally accepted benchmark for orthopedic implants.Immersed in simulated body fluid for 30 days,Zn06Mn006Mg(HE)and Zn08Mn005Mg(HE)exhibit corrosion rates of 38 and 53μm y^(-1),respectively.They show high antibacterial rates of 93%-97%against E.coli.In 25%-75%extracts of both the alloys,MC3T3-E1 cell viabilities for 1 day and 3 days are all over 100%,indicating complete cytocompatibility.In 100%extracts for 3 days,both alloys show non-toxicity.After a longtime room temperature storage of 72 weeks,natural embrittling alike Zn-Mg alloys does not happen.The Zn-Mn-Mg alloys still have mechanical properties exceeding the benchmark by a large margin.The in vitro study shows the newly developed BHSDLA Zn-Mn-Mg alloys are promising candidates for orthopedic implants.

关键词： Biodegradable Zn alloys Orthopedic implants Microstructure Mechanical properties Biocompatibility

Microstructural characterization and mechanical properties of(TiC+TiB)/TA15 composites prepared by an in-situ synthesis method

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China Foundry 2024年第2期21卷 168-174页

作者： zhi-yong zhang Jiao-jiao Cheng Jia-qi Xie shi-bing Liu Kun shi Jun Zhao Shenyang Research Institute of Foundry Co. Ltd.CAMShenyang 110022China National Key Laboratory of Advanced Casting Technologies Shenyang 110022China

Titanium matrix composites reinforced with ceramic particles are considered a promising engineering material due to their combination of high specific strength,low density,and high modulus.In this study,the TA15-based composites reinforced with a volume fraction of 10% to 25%(TiB+TiC)were prepared using powder metallurgy and casting technique.Microstructural characterization and phase constitution were examined using optical microscopy(OM),scanning electron microscopy(SEM),and X-ray diffraction(XRD).In addition,the microhardness,room temperature(RT)and high temperature(HT)tensile properties of the composites were evaluated.Results revealed that the reinforcements are distributed uniformly even in the composites with a high volume of TiB and TiC.However,as the volume fraction exceeds 15%,TiB and TiC particles become coarsening and exhibit rod-like and dendritic-like morphology.Microhardness increases gradually from 321.2 HV for the base alloy to a maximum of 473.3 HV as the reinforcement increases to 25vol.%.Tensile test results indicate that a reinforcement volume fraction above 20% is beneficial for enhancing tensile strength and yield strength at high temperatures,but it has an adverse effect on room temperature elongation.Conversely,if the reinforcement volume fraction is below 20%,it can improve high-temperature elongation when the temperature exceeds 600℃.

关键词： titanium matrix composites microstucture microhardness tensile properties in-situ synthesis

Hierarchical microstructure and two-stage corrosion behavior of a high-performance near-eutectic Zn-Li alloy

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Journal of Materials Science & Technology 2021年第21期80卷 50-65页

作者： Zhen Li Zhang-Zhi Shi Hai-Jun zhang Hua-Fang Li Yun Feng Lu-Ning Wang Beijing Advanced Innovation Center for Materials Genome Engineering School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing100083China Beijing Laboratory of Metallic Materials and Processing for Modern Transportation University of Science and Technology BeijingBeijing100083China Department of Interventional and Vascular Surgery The Tenth People's Hospital of ShanghaiTongji UniversityShanghai200072China National United Engineering Laboratory for Biomedical Material Modification Branden Industrial ParkQihe Economic&Development ZoneDezhou CityShandongDezhou251100China Ophthalmology Department Peking University Third HospitalPeking UniversityBeijing100083China

In order to improve mechanical and corrosion properties of biodegradable pure Zn,a knowledge-based microstructure design is performed on Zn-Li alloy system composed of hard β-LiZn_(4) and soft Zn phases.Precipitation and multi-modal grain structure are designed to toughen β-LiZn_(4) while strengthen Zn,resulting in high strength and high ductility for both the phases.Needle-like secondary Zn precipitates form in β-LiZn4,while fine-scale networks of string-like β-LiZn4 precipitates form in Zn with a tri-modal grain structure.As a result,near-eutectic Zn-0.48 Li alloy with an outstanding combination of high strength and high ductility has been fabricated through hot-warm rolling,a novel fabrication process to realize the microstructure design.The as-rolled alloy has yield strength(YS) of 246 MPa,the ultimate tensile strength(UTS) of 395 MPa and elongation to failure(EL) of 47 %.Immersion test in simulated body fluid(SBF) for 30 days reveals that Li-rich products form preferentially at initial stage,followed by Zn-rich products with prolonged time.Aqueous insoluble Li_(2) CO_(3) forms a protective passivation film on the alloy surface,which suppresses the average corrosion rate from 81.2 μm/year at day one down dramatically to 18.2 μm/year at day five.Afterwards,the average corrosion rate increases slightly with decrease of Li2 CO_(3) content,which undulates around the clinical requirements on corrosion resistance(i.e.,20 μm/year) claimed for biodegradable metal stents.

关键词： Zn alloy Microstructure design Mechanical properties Interfacial structure Corrosion passivation

Fabrication and characterization of novel biodegradable Zn-Mn-Cu alloys

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Journal of Materials Science & Technology 2018年第6期34卷 1008-1015页

作者： Zhang-Zhi Shi Jing Yu Xue-Feng Liu Lu-Ning Wang School of Materials Science and Engineering University of Science and Technology Beijing

Zn-Mn-Cu alloys with micro-alloying of Mn and Cu in Zn are developed as potential biodegradable met- als. Although the as-cast alloys are very brittle, their ductilities are significantly improved through hot rolling. Among the as-cast and the as-hot-rolled alloys, as-hot-rolled Zn-0.35Mn-0.41 Cu alloy has the best comprehensive property. It has yield strength of 198.4 ± 6.7 MPa, tensile strength of 292.4 ± 3.4 MPa, elongation of 29.6 ±3.8% and corrosion rate of 0.050-0.062 mm a^-1. A new ternary phase is characterized and determined to be MnCuZn18, which is embedded in MnZn13, resulting in a coarse cellular/dendritic MnZna3-MnCuZn18 compound structure in Zn-0.75 Mn-0.40Cu alloy. Such a coarse compound structure is detrimental for wrought alloy properties, which guides future design of Zn-Mn-Cu based alloys. The preliminary research indicates that Zn-Mn-Cu alloy system is a promising candidate for potential cardiovascular stent applications.

关键词： Zn alloys Biodegradability Strength Ductility Corrosion behavior