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第一性原理研究钛合金中的沉淀强化

金属学报 2024年第4期60卷 537-547页

作者：程坤陈树明曹烁刘建荣马英杰范群波程兴旺杨锐胡青苗中国科学院金属研究所师昌绪先进材料创新中心沈阳110016 中国科学技术大学材料科学与工程学院沈阳110016 北京理工大学材料学院冲击环境材料技术重点实验室北京100081

为研究合金化对沉淀强化行为的影响,采用第一性原理方法计算了二元Ti-xM(M=Al、V、Cr、Mn、Fe、Co、Ni、Zr、Nb、Mo、Ta、W)合金弹性模量随成分的变化,提出了弹性模量Mo当量概念,以高效计算复杂成分钛合金(如Ti-Al-V合金以及Ti55521)的... 详细信息

为研究合金化对沉淀强化行为的影响,采用第一性原理方法计算了二元Ti-xM(M=Al、V、Cr、Mn、Fe、Co、Ni、Zr、Nb、Mo、Ta、W)合金弹性模量随成分的变化,提出了弹性模量Mo当量概念,以高效计算复杂成分钛合金(如Ti-Al-V合金以及Ti55521)的弹性模量;结合弹性模量及Russell-Brown沉淀强化模型,研究了二元Ti-xM(M=V、Cr、Mn、Fe、Co、Ni、Nb、Mo、Ta、W)合金以及Ti55521合金中的沉淀强化。结果显示,在体积分数及沉淀相颗粒尺寸相同的情况下,Co、Fe、W、Mo、Ni、Mn沉淀强化作用较强,Cr、Nb、Ta强化作用居中,V强化作用最弱。随合金元素含量x增加,沉淀强化作用均有所增强。热机械处理Ti55521合金经短时时效后,沉淀强化作用有所减弱,但长时时效后,沉淀强化效果增强。

关键词：第一性原理钛合金弹性模量沉淀强化强度

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Finite Element Prediction of Residual Stress in Rhombic Dodecahedron Ti‑6Al‑4V Titanium Alloy Additively Manufactured by Electron Beam Melting

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Acta Metallurgica Sinica(English Letters) 2023年第1期36卷 35-47页

作者： Shangzhou Zhang Yuankang Wang Bing Zhou Fanchao Meng hua Zhang Shujun Li qingmiao hu Li Zhou Institute for Advanced Studies in Precision Materials Yantai UniversityYantai 264005China School of Electromechanical and Automotive Engineering Yantai UniversityYantai 264005China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China

In this work,a three-dimensional nonlinear transient thermo-mechanically coupled finite element model(FEM)is established to investigate the variation in temperature and stress fields during electron beam melting(EBM)of rhombic dodecahedron Ti-6Al-4V *** influence of the processing parameters on the temperature and residual stress evolutions was predicted and verified against existing literature *** calculated results indicate that the interlayer cooling time has very little effect on both the temperature and stress evolutions,indicating that the interlayer cooling time can be set up as short as possible to reduce manufacturing *** is presented that the residual stress of the intersection is higher than that of *** increasing preheating temperature,the residual stress decreases continuously,which is about 20%–30%for every 50℃rise in *** temperature and stress fields repeated every four layers with the complex periodic scanning *** x and y-component residual stresses are tensile stresses,while z-component stress is weak compressive or tensile stress in typical *** is proposed that the interlayer cooling is necessary to obtain a rhombic dodecahedron with low residual *** results can bring insights into the understanding of the residual stress during EBM.

关键词： Electron beam melting Ti-6Al-4V Rhombic dodecahedron Residual stress Finite element analysis Parametric study

A Comparative Study of Elastic Constants of NiTi and NiAl Alloys from First-Principle Calculations

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Journal of Materials Science & Technology 2009年第2期25卷 215-218页

作者： Jianmin Lu qingmiao hu Rui Yang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

To investigate the origin of the strong dependence of martensitic transformation temperature on composition, the elastic properties of high temperature B2 phases of both NiTi and NiAI were calculated by a first-principle method, the exact-muffin orbital method within coherent potential approximation. In the composition range of 50-56 at. pct Ni of NiTi and 60-70 at. pct Ni of NiAI in which martensitic transformation occurs, non-basalplane shear modulus c44 increases with increasing Ni content, while basal-plane shear modulus c＇ decreases. In the above composition ranges however the transformation temperature of NiAI increases with increasing Ni content while that of NiTi decreases from experimental observation. The softening of c＇ is experimentally observed only in NiAI, and the decrease of c＇ with increasing Ni content is responsible for the increase of transformation temperature. The result of the present work demonstrates that, besides c＇, c44 also influences the martensitic transformation of NiTi and plays quite important a role.

关键词： NiTi NiA1 Elastic constant First-principle calculation

Composition dependent elastic modulus and phase stability of Ni_2MnGa based ferromagnetic shape memory alloys

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Science China(Technological Sciences) 2012年第2期55卷 295-305页

作者： hu qingmiao LUO huBin LI ChunMei VITOS Levente YANG Rui Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Applied Materials Physics Department of Materials Science and EngineeringRoyal Institute of TechnologyStockholm SE-10044Sweden Condensed Matter Theory Group Physics DepartmentUppsala UniversityUppsala SE-75120Sweden Research Institute for Solid State Physics and Optics P.O.Box 49Budapest H-1525Hungary

Ni2MnGa based ferromagnetic alloys are ideal candidates for applications such as actuators,magnetic refrigerators or magnetostrictive transducers due to their attractive properties such as magnetic field induced shape memory effect and large magnetocaloric *** properties of these alloys(e.g.,the martensitic transformation temperature TM) sensitively depend on the *** the composition dependence of these properties so as to design the alloy as desired is one of the main research topics in this *** recent years,we have investigated the composition dependent elastic modulus and phase stability of Ni2MnGa-based alloys by using a first-principles method,in hope of clarifying their connection to the properties of these *** this article,we review the main results of our *** show that the tetragonal shear modulus C' is a better predictor of the composition dependent TM than the number of valence electrons per atom(e/a) since the general TM^C' correlation works for some of the alloys for which the TM^e/a correlation fails,although there exist several cases for which both the general TM^C' and TM^e/a correlations break *** the experimentally determined modulation function,the complex 5-layer modulated(5M) structure of the martensite of Ni2MnGa and the Al-doping effect on it are *** find that the shuffle and shear of the 5M structure are linearly *** relative stability of the austenite and the martensites is examined by comparing their total *** non-modulated martensite ''' with the tetragonality of the unit cell c/a>1 is shown to be globally stable whereas the 5M martensite with c/a<1 is *** critical Al atomic fraction over which the martensitic transformation between the 5M martensite and austenite cannot occur is predicted to be 0.26,in reasonable agreement with experimental findings.

关键词：铁磁形状记忆合金 Ni2MnGa 相对稳定弹性模量组成马氏体相变温度相位形状记忆效应

Prediction on temperature dependent elastic constants of “soft” metal Al by AIMD and QHA

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Journal of Materials Science & Technology 2020年第10期42卷 92-97页

作者： Haijun Zhang Chenhui Li Philippe Djemia Rui Yang qingmiao hua Institute of Metal Research Chinese Academy of SciencesWenhua Road 72Shenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaJinzhai Road 96Hefei230026China LSPM-CNRS3407 Universite Paris 13Sorbonne Paris CiteVilletaneuse93430France

First-principles methods based on density functional theory(DFT)are nowadays routinely applied to calculate the elastic constants of materials at temperature of 0 ***,the first-principles calculations of elastic constants at finite temperature are not *** the present work,the feasibility of the ab initio molecular dynamic(AIMD)method in calculations of the temperature dependent elastic constants of relatively"soft"metals,taking face centered cubic(FCC)aluminum(Al)as example,is *** AIMD calculations are performed with carefully selected strain tensors and strain *** parallel with the AIMD calculations,first-principles calculations with the quasiharmonic approximation(QHA)are performed as *** show that all three independent elastic constant components(C11,C12 and C44)of Al from both the AIMD and QHA calculations decrease with increasing temperature T,in good agreement with those from experimental *** work allows us to quantify the individual contributions of the volume expansion,lattice vibration(excluding those contributed to the volume expansion),and electronic temperature effects to the temperature induced variation of the elastic *** Al with stable FCC crystal structure,the volume expansion effect contributes the major part(about 75%~80%)in the temperature induced variation of the elastic *** contribution of the lattice vibration is minor(about 20%~25%)while the electronic temperature effect is *** the elastic constants soften with increasing temperature,FCC Al satisfies the Born elastic stability criteria with temperature up to the experimental melting point.

关键词： Elastic constant First-principle Molecular dynamics Vibration Aluminum

Precipitates and alloying elements distribution in nearαtitanium alloy Ti65

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Journal of Materials Science & Technology 2020年第1期36卷 91-96页

作者： Ke Yue Jianrong Liu Haijun Zhang hui Yu Yuanyuan Song qingmiao hu Qingjiang Wang Rui Yang Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China School of Information Science and Engineering Shenyang University of TechnologyShenyang 110870China

Precipitates,including silicides and Ti3 Al(α2)phase,and alloying elements distribution in a near a titanium alloy Ti65(Ti-5.8 Al-4.0 Sn-3.5 Zr-0.5 Mo-0.3 Nb-1.0 Ta-0.4 Si-0.8 W-0.05 C)after solution treatment and aging process were characterized by using transmission electron microscopy(TEM)and atom probe tomography(APT).Quantitative composition analysis and TEM observation indicate that the silicides fit to(Ti,Zr)6(Sl,Sn)*** exhibits aβ-stabilizing effect in near a titanium alloys but is weaker than otherβstabilizing *** enriching tendency of the alloying elements in the retainedβphase is in the order of Zr

关键词： Atom probe tomography Titanium alloys Precipitation First-principles calculation Alloying elements distribution

R-matrix for the 8-Dimensional Spin Representation of Uq(so7)

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Acta Mathematica Sinica,English Series 2024年第2期40卷 485-497页

作者： Hong Mei hu Nai Hong hu School of Mathematical Sciences Suzhou University of Science and TechnologySuzhou 215009P.R.China School of Mathematical Sciences MOE Key Laboratory of Mathematics and Engineering Applications&Shanghai Key Laboratory of PMMPEast China Normal UniversityShanghai 200241P.R.China

The purpose of the paper is to describe the solution to the quantum Yang-Baxter equation associated with the 8-dimensional spin representation Tsp of Uq(so7).The self-duality of Tsp and the symmetry of the corresponding braiding matrix are ***,the minimal polynomial of the braiding R-matrix of Tsp is presented explicitly in an ingenious method by taking advantage of nice features of the spin representation Tsp.

关键词： Braiding R-matrix spin module minimal polynomial

Mapping out the reaction network of humin formation at the initial stage of fructose dehydration in water

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Green Energy & Environment 2024年第6期9卷 1016-1026页

作者： Xing Fu Yexin hu Ping hu hui Li Shuguang Xu Liangfang Zhu Changwei hu Key Laboratory of Green Chemistry and Technology Ministry of EducationCollege of ChemistrySichuan UniversityChengduSichuan610064China State Key Laboratory of Southwestern Chinese Medicine Resources Innovative Institute of Chinese Medicine and PharmacyChengdu University of Traditional Chinese MedicineChengduSichuan611137China

The formation of humins hampers the large-scale production of 5-hydroxymethylfurfural(HMF)in ***,a detailed reaction network of humin formation at the initial stage of fructose-to-HMF dehydration in water is delineated by combined experimental,spectroscopic,and theoretical *** bimolecular reaction pathways to build up soluble humins are *** is,the intermolecular etherification of β-furanose at room temperature initiates the C12 path,whereas the C-C cleavage of a-furanose at 130-150℃ leads to C11 path,and that of open-chain fructose at 180℃ to C11' *** successive intramolecular dehydrations and condensations of the as-formed bimolecular intermediates lead to three types of soluble *** show that the C12 path could be restrained by using HCl or AlCl_(3) catalyst,and both the C12 and C110 paths could be effectively inhibited by adding THF as a co-solvent or accelerating heating rate via microwave heating.

关键词： Carbohydrates 5-hydroxymethylfurfural Reaction network Soluble humins Tautomer

Investigation of mechanical and electrical characteristics of selfsensing pneumatic torsional actuators

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Science China(Technological Sciences) 2024年第1期67卷 130-142页

作者： XIAO Wei hu DeAn hu GuoLiang XIAO Yihua Key Laboratory of Conveyance and Equipment Ministry of EducationEast China Jiaotong UniversityNanchang 330013China Key Laboratory of Advanced Design and Simulation Techniques for Special Equipment Ministry of EducationHunan UniversityChangsha 410082China

Soft pneumatic actuators are one of the most promising actuation for soft robots,and great achievements have been *** it remains challenging to endow sensing capabilities to pneumatic actuators,especially for the sensing ability originating directly from the actuator ***,a self-sensing pneumatic torsional actuator(SPTA)is designed based on the electromagnetic induction effect and magnetically responsive *** SPTA can generate feedback voltage and current with the deformation,in which the sensing function comes from its inherent *** investigate the mechanical and electrical characteristics,an experimental platform and a finite element model are established,*** find that the torsion angle and output torque increase in nonlinear with the actuating *** maximum torsion angle is 66.35°,which is 84.34%of that for the actuator fabricated by pure *** maximum output torque(24.9 N mm)improves by 23.19%compared with the actuator made by pure *** regards the electrical characteristics,the maximum feedback voltage and current are 2.90μV and 29.50 nA when the SPTA is actuated by a pressure of−40 *** also demonstrate that the relationship between the torsion angle and the magnetic flux change is approximately ***,the number of turns of wires,magnetic powders contents,and magnetic direction on the feedback voltage and current are *** show that the feedback voltage and current can be enhanced by increasing the number of turns and magnetic powders *** envision that the SPTA would be promising for soft robots to realize their accuracy control and intelligentization.

关键词： pneumatic torsional actuators self-sensing feedback voltage finite element modeling soft robots