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Toward developing Ti alloys with high fatigue crack growth resistance by additive manufacturing

Journal of materials Science & Technology 2023年第1期132卷 166-178页

作者： F.Wang L.m.Lei X.Fu L.Shi X.m.Luo z.m.song G.P.zhang Shenyang National Laboratory for materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China AECC Commercial Aircraft Engine Co. Ltd.Shanghai 201306China

Fatigue crack growth behaviors were investigated by three-point bending tests for TA19 alloy fabricated by laser metal deposition and four kinds of heat-treated samples.The crack growth resistance of the TA19 samples in the near-threshold regime and Paris regime was evaluated through the experimental characterization and theoretical analysis of the interaction between fatigue crack andα/βphase inter-face,columnar prior-βgrain boundary and colony boundary.The results show that in the near-threshold regime,the fatigue crack propagation threshold and resistance increase with the increase of widths of lamellarαp phases and colonies,and the decrease of the number ofαlaths with an angle(ϕ)relative to the applied stress direction ranging from 75°to 90°.In the Paris regime,the fatigue cracking path can be deflected at colony boundaries or columnar prior-βgrain boundaries.The larger the deflection angle,the more tortuous the cracking path and the lower the fatigue crack growth rate.The angle(γ)of the columnar prior-βgrain growth direction relative to the build direction affects not onlyϕof differentαvariants,but also the fatigue cracking path deflection angle(θij)at columnar prior-βgrain boundaries.An optimal combination ofγ=0°-15°-0°-15°for several adjacent columnar prior-βgrains is derived from the theoretical analysis,and that can effectively avoidϕbeing in the range from 75°to 90°and makeθij as large as possible.Such findings provide a guide for the selection of scanning strategies and process parameters to additively manufacture Ti alloys with high fatigue damage tolerance.

关键词： Ti alloy Fatigue crack growth Additive manufacturing Phase interface Grain boundary

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Geometrical Scale-Sensitive Fatigue Properties of Ti-6.5Al-3.5mo-1.5zr-0.3Si Alloys With α/β Lamellar microstructures

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Journal of materials Science & Technology 2014年第12期30卷 1284-1288页

作者： B.zhang z.m.song L.m.Lei L.Kang G.P.zhang Key Laboratory for Anisotropy and Texture of materials Ministry of Education Northeastern University Shenyang National Laboratory for materials Science Institute of Metal Research Chinese Academy of Sciences AVIC Commercial Aircraft Engine Co. Ltd.

Fatigue properties of the Ti-6.5Al-3.5mo-1.5zr-0.3Si alloy sheets containing different numbers of α/β Widmansttten colonies in the thickness direction of the sheets were investigated by tensionetension fatigue testing. It is found that fatigue properties of the Ti alloy either in low- or high-stress amplitude regimes become more sensitive to the sheet thickness of the Ti alloy as the sheet thickness is comparable to the length scale of the Widmansttten colonies. The basic mechanism of such length scale-sensitive fatigue properties in the Ti alloy was elucidated.

关键词： Fatigue Ti alloy microstructure Size effect

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microstructural Evolution and Service Performance of Cold-drawn Pure Aluminum Conductor Wires

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Journal of materials Science & Technology 2017年第9期33卷 1039-1043页

作者： X.m.Luo z.m.song m.L.Li Q.Wang G.P.zhang Shenyang National Laboratory for materials Science Institute of Metal ResearchChinese Academy of Sciences

microstructures and service performance(mechanical and electrical properties) of the commercially pure Al conductor wires subjected to different cold drawing strains were investigated. The results show that the microstructures of the cold-drawn Al wires along the radial direction were inhomogeneous, i.e. the texture in the center region was strong and weak components, while that in the surface region shifted from the initial cubic texture to a component and finally developed into a strong component. The volume fraction of the high angle grain boundaries in the surface region was higher than that in the center region. The cold-drawing process greatly enhanced the yield strength of the pure Al wires while retained the acceptable electrical resistivity. The strengthening mechanism and the variation of electrical conductivity of the cold-drawn Al wires are discussed through correlating with microstructure evolution.

关键词： Cold drawing Aluminum microstructure Strength Conductivity

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On Temperature and Strain Rate Dependent Strain Localization Behavior in Ti-6.5Al-3.5mo-1.5zr-0.3Si Alloy

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Journal of materials Science & Technology 2013年第3期29卷 273-278页

作者： B.zhang L.m.Lei X.L.Jiang z.m.song X.Huang G.P.zhang Key Laboratory for Anisotropy and Texture of materials(ministry of Education) Northeastern University Titanium Alloys Laboratory Beijing Institute of Aeronautical Materials AVIC commercial Aircraft Engine Co. Ltd. Shenyang National Laboratory for materials Science Institute of Metal ResearchChinese Academy of Sciences

Deformation behaviors of Ti-6.5Al-3.5mo-1.5zr-0.3Si alloys with α/β lamellar structure were investigated systematically at different temperatures from room temperature to 950 ~C and different strain rates. Results reveal that when the deformation temperature is higher than a critical temperature of 600℃, an evident transition of deformation behavior from localized shear banding to α/β lamella kinking, flow softening and temperature/strain rate-dependent peak flow stress occurred in the alloy. The critical conditions for the occurrence of internal cracking and strain localization behavior associated with temperature and strain rate were determined.

关键词： Titanium alloy Hot working Temperature Strain rate Shear band

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用于确定速度和衰减的2.5D全波井间反演法

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石油物探译丛 1994年第3期 70-72页

作者： z.m.song 徐仪征

在不同的二维问题(例如2.5维结构)情况中,song和Williamson(1992)曾介绍过一种三维震源波场的精确模拟方法。本文介绍了一种频率域波场反演法,利用此法可将Pratt(1989)的方法扩展用于2.5维。因为动力学方法是正确的,所以计算的波场在没... 详细信息

在不同的二维问题(例如2.5维结构)情况中,song和Williamson(1992)曾介绍过一种三维震源波场的精确模拟方法。本文介绍了一种频率域波场反演法,利用此法可将Pratt(1989)的方法扩展用于2.5维。因为动力学方法是正确的,所以计算的波场在没有明显的平界面变化情况下可直接与实际数据对比,并可进行非线性迭代反演。按照Tarantola(1984)的观点,反演可表述为最小二乘方最优化问题,并利用Born线性近似导出给定模型的梯度方向。本方法的潜在效率是很高的,因为每次迭代只有一个频率分量需要估算。在开始时频率应该很低,这样可避免周期跳跃效应,然后在反演时可加大频率,以便提高分辨率。在恒密度声学介质情况下,衰减可看作速度场的虚部,它很容易包括在反演中。此方法无需对频率与衰减的关系做任何假设,其潜在效率已用含断层层状模型上计算的合成数据集作了证明。该速度(即速度实部)几乎可恢复到现有频率所能达到的分辨率极限。虽然衰减恢复的精度较低,但仍然可用。

关键词：速度衰减地震波地震数据

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Editorial for Special Issue on Commonsense Knowledge and Reasoning:Representation,Acquisition and Applications

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machine Intelligence Research 2024年第2期21卷 215-216页

作者： Kang Liu Yangqiu song Jeff z.Pan Institute of Automation Chinese Academy of SciencesChina Hongkong University of Science and Technology China The University of Edinburgh UK

Commonsense knowledge is an important resource for humans to understand the meanings or semantics of the data.The ability to learn and own commonsense knowledge is one of the major gaps between humans and machines.Although recent research progresses about deep learning,like Transformer,pre-trained models,etc.,have made amazing breakthroughs in many fields,including computer version,natural language learning,etc.,letting the machines have rich commonsense knowledge and possess the reasoning ability is still difficult and under-resolved.

关键词： own let breakthrough

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Flat Band and η-Pairing States in a One-Dimensional moiréHubbard model

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Chinese Physics Letters 2024年第4期41卷 69-76页

作者：王冉宋智 College of Physics and materials Science Tianjin Normal UniversityTianjin 300387China School of Physics Nankai UniversityTianjin 300071China

A moirésystem is formed when two periodic structures have a slightly mismatched period,resulting in unusual strongly correlated states in the presence of particle-particle interactions.The periodic structures can arise from the intrinsic crystalline order and periodic external field.We investigate a one-dimensional Hubbard model with periodic on-site potential of period n_(0),which is commensurate to the lattice constant.For large n_(0),the exact solution demonstrates that there is a midgap flat band with zero energy in the absence of Hubbard interaction.Each moiréunit cell contributes two zero energy levels to the flat band.In the presence of Hubbard interaction,the midgap physics is demonstrated to be well described by a uniform Hubbard chain in which the effective hopping and on-site interaction strength can be controlled by the amplitude and period of the external field.Numerical simulations are performed to demonstrate the correlated behaviors in the finite-sized moiré Hubbard system,including the existence of an η-pairing state and bound pair oscillation.This finding provides a method to enhance the correlated effect by a spatially periodic external field.

关键词： oscillation interaction field

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Effects of multiple shapes for steady flow with transformer oil+Fe_(3)O_(4)+TiO_(2) between two stretchable rotating disks

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Applied mathematics and mechanics(English Edition) 2024年第2期45卷 373-388页

作者： m.RAHmAN m.TURKYILmAzOGLU z.mUSHTAQ Department of mathematics Mirpur University of Science and TechnologyMirpur 10250Pakistan Department of mathematics Hacettepe UniversityBeytepeAnkara 06532Turkiye

In this study,we examine the effects of various shapes of nanoparticles in a steady flow of hybrid nanofluids between two stretchable rotating disks.The steady flow of hybrid nanofluids with transformer oil as the base fluid and Fe_(3)O_(4)+TiO_(2)as the hybrid nanofluid is considered.Several shapes of Fe_(3)O_(4)+TiO_(2)hybrid nanofluids,including sphere,brick,blade,cylinder,and platelet,are studied.Every shape exists in the same volume of a nanoparticle.The leading equations(partial differential equations(PDEs))are transformed to the nonlinear ordinary differential equations(ODEs)with the help of similarity transformations.The system of equations takes the form of ODEs depending on the boundary conditions,whose solutions are computed numerically by the bvp4c mATLAB solver.The outputs are compared with the previous findings,and an intriguing pattern is discovered,such that the tangential velocity is increased for the rotation parameter,while it is decreased by the stretching values because of the lower disk.For the reaction rate parameter,the concentration boundary layer becomes shorter,and the activation energy component increases the rate at which mass transfers come to the higher disk but have the opposite effect on the bottom disk.The ranges of various parameters taken into account are Pr=6.2,Re=2,m=1.0,φ_(1)=φ_(2)=0.03,K=0.5,S=-0.1,Br=0.3,Sc=2.0,α_(1)=0.2,γ=0.1,E_(n)=2.0,and q=1.0,and the rotation factor K is within the range of 0 to 1.

关键词： transformer oil Brinkman number skin friction coefficient double rotating disk Nusselt number Sherwood number

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Dysregulation of RNA modification systems in clinical populations with neurocognitive disorders

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Neural Regeneration Research 2024年第6期19卷 1256-1261页

作者： Helen m.Knight merve Demirbugen ?z Adriana PerezGrovas-Saltijeral Division of Cells Organisms and Molecular Genetics School of Life Sciences University of Notingham Department of Pharmaceutical Toxicology Faculty of Pharmacy Ankara University

The study of modified RNA known as epitranscriptomics has become increasingly relevant in our understanding of disease-modifying mechanisms. methylation of N6 adenosine(m6A) and C5 cytosine(m5C) bases occur on mRNAs, tRNA, mt-tRNA, and rRNA species as well as non-coding RNAs. With emerging knowledge of RNA binding proteins that act as writer, reader, and eraser effector proteins, comes a new understanding of physiological processes controlled by these systems. Such processes when spatiotemporally disrupted within cellular nanodomains in highly specialized tissues such as the brain, give rise to different forms of disease. In this review, we discuss accumulating evidence that changes in the m6A and m5C methylation systems contribute to neurocognitive disorders. Early studies first identified mutations within FmR1 to cause intellectual disability Fragile X syndromes several years before FmR1 was identified as an m6A RNA reader protein. Subsequently, familial mutations within the m6A writer gene mETTL5, m5C writer genes NSUN2, NSUN3, NSUN5, and NSUN6, as well as THOC2 and THOC6 that form a protein complex with the m5C reader protein ALYREF, were recognized to cause intellectual development disorders. Similarly, differences in expression of the m5C writer and reader effector proteins, NSUN6, NSUN7, and ALYREF in brain tissue are indicated in individuals with Alzheimer’s disease, individuals with a high neuropathological load or have suffered traumatic brain injury. Likewise, an abundance of m6A reader and anti-reader proteins are reported to change across brain regions in Lewy bodies diseases, Alzheimer’s disease, and individuals with high cognitive reserve. m6A-modified RNAs are also reported significantly more abundant in dementia with Lewy bodies brain tissue but significantly reduced in Parkinson’s disease tissue, whilst modified RNAs are misplaced within diseased cells, particularly where synapses are located. In parahippocampal brain tissue, m6A modification is enriched in transcripts associated with psychiatri

关键词： 5-methylcytosine methylation Alzheimer’s disease cognitive diseases epitranscriptomics intellectual disability Lewy body diseases N6 adenosine RNA modification

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Chronic administration of triclosan leads to liver fibrosis through hepcidin-ferroportin axis-mediated iron overload

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Journal of Environmental Sciences 2024年第3期137卷 144-154页

作者： Jing Liu Lecong zhang Fang Xu Ping zhang Yang song College of Eco-Environmental Engineering Guizhou Minzu UniversityGuiyang 550025China The Institute of Karst Wetland Ecology Guizhou Minzu UniversityGuiyang 550025China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

Triclosan(TCS)has been manufactured as an antibacterial compound for half a century.Currently,it is widely used in various personal care products;however,its potential adverse effects raise a lot of attention.Here,we create a long-term oral administration mouse model and identify the corresponding hepatotoxicity of TCS.We discover that daily intragastric administration of 10 mg/kg TCS to mice for 12 weeks results in severe hepatic fibrosis.Further study displays that hepatic iron increased 18%,23%and 29%upon oral TCS treatment for4,8 and 12 weeks,respectively.Accompanied by hepatic iron variation,splenic and duodenal iron are increased,which indicates systemic iron disorder.Not only excessive iron accumulated in the liver,abnormal hepatic malondialdehyde,prostaglandin synthase 2 and glutathione peroxidase 4 are pointed to ferroptosis.Additional study uncovers that hepcidin expression increases 7%,10%,4%in serum and 2.4-,4.8-,and 2.3-fold on transcriptional levels upon TCS exposure for 4,8 and 12 weeks,individually.Taken together,the mice in the TCS-treated group show disordered systemic iron homeostasis via the upregulated hepatic hepcidin-ferroportin axis.meanwhile,both hepatic iron overload(systemic level)and hepatocyte ferroptosis(cellular level)are accused of TCS-induced liver fibrosis.Ferriprox■,an iron scavenger,significantly ameliorates TCS-induced liver fibrosis.In summary,this study confirms the impact of TCS on liver fibrosis;a critical signal pathway is also displayed.The significance of the current study is to prompt us to reevaluate the“pros and cons”of TCS applications.

关键词： Triclosan Iron metabolism Hepcidin Hepatotoxicity Liver fibrosis

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