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COMPOSITION EFFECT ON DRy SLIDING WEAR BEhAVIORS OF Ti-B-N ThIN FILMS

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 300-306页

作者： P.Sit y.h.Lu h.Chen z.F.zhou y.G.Shen K.y.Li DepartmentofPhysicsandMaterialsScience CityUniversityofHongKongKowloonHongKongChina DepartmentofPhysicsandMaterialsScience CityUniversityofHongKongKowloonHongKongChina／／DepartmentofManufacturingEngineeringg：EngineeringManagementCityUniversityofHongKongKowloonHongKongChina DepartmentofManufacturingEngineering＆EngineeringManagement CityUniversityofHongKongKowloonHongKongChina

Friction and sliding wear behaviour of Ti-B-N coatings against AISI440C steel ba ll and WC-6wt%Co ball were studied by using pin-on-disk tribometer along with mi crostructure characterization using optical microscopy (OM), scanning electron m icroscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It is shown that the wear resistance of film depended on the wear mechanism. In the case of AISI440C steel, adhesive wear were pre-dominant and the wear rate increased sharply to a maximum when N content reach ~38at.%. This might be related to the change of fi lm microstructure and phase configuration, so the least adhesive transfer of tri bo-film was observed. If WC-6wt%Co ball was used, less deformation wear debris w as observed, this was responsible for the rise of wear rate. Despite of differen t wear modes, friction coefficients in both cases were found to depend mainly on the formation and the amount of h-BN phase. Elemental analysis by energy disper sive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) revealed that oxygen participated in the wear behavior by reacting with films to form the deb ris comprised of various types of Ti oxide including TiO, TiO2 and Ti2O3 , which increased wear resistance.

关键词： dry sliding wear friction coefficient oxidation Ti-B-N wear

Microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with different prestrain levels

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Journal of Materials Science & Technology 2024年第4期171卷 80-93页

作者： y.h.zhang h.Li z.W.yang X.Liu Q.F.Gu State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of high-Performance Precision Forming Technology and Equipment Northwestern Polytechnical UniversityXi’an 710072China

Ni_(47)Ti_(44)Nb_(9)shape memory alloy(SMA)is a promising material in the aerospace field due to its wide transformation *** application of shape memory effect depends on multistep thermomechan-ical loading,viz.,low-temperature deformation and subsequent heating to ***-temperature deformation prestrain plays a pivotal role in shape memory properties tailoring of SMA ***,microstructure evolution and deformation mechanisms of Ni_(47)Ti_(44)Nb_(9)SMA subjected to vari-ous prestrain levels are still *** this end,microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with prestrain levels of 8%-16%at-28℃(M_(s)+30℃)were *** results demonstrate that the stress-strain curve of the specimen exhibits four distinct stages at a maximal prestrain of 16%.Whereas stageⅡand stageⅢend at prestrains of∼8%and∼12%,*** stageⅡ,the stress-induced martensitic transformation is accompanied by the dislocation slip of the NiTi matrix andβ-Nb *** stageⅢ,in addition to the higher density of dislocations and further growth of stress-induced martensite variants(SIMVs),(001)compound twins are introduced as a result of the(001)deformation twinning in stress-induced ***{20-1}martensite twins are gradually introduced in stageⅣ.Correspondingly,after subsequent unloading and heating,a higher density of{114}austenite twins form in the specimen with a larger prestrain of 16%.With increasing prestrain from 8%to 16%,the recoverable strainε_(re)^(T)upon heating increases first and then ***ε_(re)^(T)obtains a maximum of 7.03%at 10%prestrain and de-creases to 6.17%at 16%*** increase ofε_(re)^(T)can be attributed to the formation of new SIMVs,the further growth of existing SIMVs,and the recoverable(001)compound *** the decrease ofε_(re)^(T)is mainly associated with the irrecoverable strain by{20−1}martensite *** effe

关键词： Ni_(47)Ti_(44)Nb_(9)shape memory alloy Wide transformation hysteresis Thermomechanical loading Microstructure evolution Shape memory behaviors Stress-induced martensitic transformation Deformation twinning

Macro to nanoscale deformation of transformation-induced plasticity steels：Impact of aluminum on the microstructure and deformation behavior

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Journal of Materials Science & Technology 2018年第5期34卷 745-755页

作者： V.S.y.Injeti z.C.Li B.yu R.D.K.Misra z.h.Cai h.Ding Department of Metallurgical Materials and Biomedical Engineering500 W. University Avenue USA School of Materials Science and Engineering Northeastern University Shenyang 110819 China

This work aims to elucidate the impact of aluminum-content on microstructure and deformation mechanisms of transformation-induced plasticity（TRIP） steels through macroscale and nanoscale deformation experiments combined with post-mortem electron microscopy of the deformed *** solid-state transformation-induced mechanical deformation varied with the Al contents,and influenced tensile strength-ductility *** with 2–4 wt% Al were characterized by TRIP *** contrast to 2 Al-TRIP and 4 Al-TRIP steels,twinning-induced plasticity（TWIP） was also observed in conjunction with strain-induced martensite in 6 Al-TRIP *** behavior is attributed to the increase in stacking fault energy with the increase of Al content and stability of austenite,which depends on the local chemical *** study addresses the knowledge gap with regard to the effect of Al content on austenite stability in medium-Mn TRIP *** combination is expected to potentially enable cost-effective alloy design with high strength-high ductility condition.

关键词： Medium-manganese steels Aluminum content Electron microscopy Mechanical properties Nanoscale deformation TRIP steel Twinning

First-principles Calculation Assisted Thermodynamic Modeling of Ti-Co-Cu Ternary System

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Journal of Materials Science & Technology 2010年第4期26卷 317-326页

作者： y.J. yang X.M. Tao W.J. zhu z.h. Long h.S. Liu z.P. Jin School of Materials Science and Engineering Central South University Changsha 410083 China Key Lab of Non-ferrous Metal Science and Engineering Ministry of Education Changsha 410081 China

Thermodynamic assessment of Ti-Co-Cu ternary system has been carried out by combining first-principle calculation and CALPhAD method. Firstly, formation enthalpies of stable and hypothesized compounds were calculated by first-principles method. Then, based on reported experimental information, a thermodynamic description of the Ti-Co-Cu ternary system was performed. Solution phases were treated as substitutional solutions of which excess Gibbs energies were formulated by Redlich-Kister polynomial, and the intermediate phases were described with sublattice models. All measured isothermal sections were reasonably reproduced. In addition, liquidus projection of this ternary system was further calculated, which may be useful for relevant materials processing.

关键词： First-principle CALPhAD Thermodynamic modeling

Leveraging ROTI map derived from Indonesian GNSS receiver network for advancing study of Equatorial Plasma Bubble in Southeast/East Asia

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Earth and Planetary Physics 2025年第1期9卷 101-116页

作者： Prayitno Abadi Ihsan N.Muafiry Teguh N.Pratama Angga y.Putra Suraina Gatot h.Pramono Sidik T.Wibowo Febrylian F.Chabibi Umar A.Ahmad Wildan P.Tresna Asnawi Research Center for Climate and Atmosphere Indonesian National Research and Innovation Agency(BRIN)BandungIndonesia School of Electrical Engineering Telkom UniversityBandungIndonesia Directorate of Laboratory Management Facilities and Science and Technology Park Indonesian National Research and Innovation Agency(BRIN)PontianakIndonesia Geophysics Laboratory Master Program in PhysicsUniversitas Gadjah Mada(UGM)YogyakartaIndonesia Research Center for Space Indonesian National Research and Innovation Agency(BRIN)BandungIndonesia Indonesian Geospatial Information Agency(BIG) JakartaIndonesia Research Center for Photonics Indonesian National Research and Innovation Agency(BRIN)Tangerang SelatanIndonesia Department of Earth and Planetary Sciences Hokkaido UniversitySapporoJapan

This paper highlights the crucial role of Indonesia’s GNSS receiver network in advancing Equatorial Plasma Bubble(EPB)studies in Southeast and East Asia,as ionospheric irregularities within EPB can disrupt GNSS signals and degrade positioning *** by the Indonesian Geospatial Information Agency(BIG),the Indonesia Continuously Operating Reference Station(Ina-CORS)network comprises over 300 GNSS receivers spanning equatorial to southern low-latitude ***-CORS is uniquely situated to monitor EPB generation,zonal drift,and dissipation across Southeast *** provide a practical tool for EPB research,by sharing two-dimensional rate of Total Electron Content(TEC)change index(ROTI)derived from this *** generate ROTI maps with a 10-minute resolution,and samples from May 2024 are publicly available for further scientific *** preliminary findings from the ROTI maps of Ina-CORS are ***,the Ina-CORS ROTI maps reveal that the irregularities within a broader EPB structure persist longer,increasing the potential for these irregularities to migrate farther ***,we demonstrate that combined ROTI maps from Ina-CORS and GNSS receivers in East Asia and Australia can be used to monitor the development of ionospheric irregularities in Southeast and East *** have demonstrated the combined ROTI maps to capture the development of ionospheric irregularities in the Southeast/East Asian sector during the G5 Geomagnetic Storm on May 11,*** observed simultaneous ionospheric irregularities in Japan and Australia,respectively propagating northwestward and southwestward,before midnight,whereas Southeast Asia’s equatorial and low-latitude regions exhibited irregularities *** sharing ROTI maps from Indonesia and integrating them with regional GNSS networks,researchers can conduct comprehensive EPB studies,enhancing the understanding of EPB behavior across Southeast and East Asia and contributing significantly to ionosphe

关键词： Equatorial Plasma Bubble(EPB) GNSS receivers’network Indonesia Continuously Operating Reference Station(Ina-CORS) ionospheric map Rate of TEC change index(ROTI)map

LOW TEMPERATURE ThERMODyNAMIC STUDy OF ThE STABLE AND METASTABLE PhASES OF SILVER

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Acta Metallurgica Sinica(English Letters) 2007年第5期20卷 355-362页

作者： X.B. Li y.Q. Xie y.z. Nie h.J. Peng Research Center of Advanced Materials Xiangtan University Xiangtan 411105 China School of Material Science and Engineering University Changsha 410083 China Central South

The low temperature thermodynamics of the stable phase of silver was assessed by the polynomial model and Debye model from the experimental data available in the literature. By means of the constrained non-linear least squares curve fitting arithmetic, two sets of parameter values were determined. The expression of the thermodynamic functions cp（T） and G（T）-h （298.15K） at 0-298.15K were presented. Only the low temperature thermodynamics of the metastable phase of silver can be extrapolated by the Debye model The expression of the thermodynamic functions cp（T） at 0- 298.15K was presented.

关键词： silver thermodynamic heat capacity SGTE (Scientific Group Thermodata Europe)

A novel Mg-Gd-y-zn-Cu-Ni alloy with excellent combination of strength and dissolution via peak-aging treatment

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Journal of Magnesium and Alloys 2023年第2期11卷 720-734页

作者： y.h.Liu z.R.zhang J.Wang y.Li h.X.Li L.y.Jia J.h.Wang J.S.zhang State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Dekai Intelligent Casting Co. Ltd.Hebei 072750China

Inferior absolute strength and dissolution properties are the main bottlenecks for the widespread application of dissolvable magnesium alloys in complex working environments for unconventional oil and gas ***,a novel functional peak-aged Mg-9.5Gd-2.7y-0.9zn-0.8Cu-0.4Ni(wt.%) alloy for fracturing tools is reported,and it possesses an ultimate tensile strength of 457.6 MPa,ultimate compressive strength of 620.7 MPa and dissolution rate of ~43.7 mg·cm^(-2)·h^(-1) in 3 wt.% KCl solutions at 93℃.The excellent strength of the agedalloy is primarily attributed to the combination of grain refinement,long-period stacking ordered(LPSO) strengthening,and precipitation strengthening induced by stacking fault and β’ phase,among which the precipitation strengthening is *** investigations confirm that the corrosion is triggered from the micro-galvanic coupling between the Mg matrix and the cathodic lamellar and block LPSO ***-shaped corrosion pits along with LPSO phases are subsequently formed,significantly accelerating *** β’ precipitates can effectively improve the strength without compromising the dissolution rate because of their nanoscale *** study provides an excellent material selection for dissolvable fracturing tools and presents a strategy by which a synergistic combination of strength and dissolution rate is achieved via peak-aging treatment.

关键词： Dissolvable magnesium alloy Peak-aging treatment Mechanical properties Micro-galvanic corrosion

Dual Topological Features of Weyl Semimetallic Phases in Tetradymite BiSbTe_(3)

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Chinese Physics Letters 2021年第7期38卷 69-73页

作者： z.z.zhou h.J.Liu G.y.Wang R.Wang X.y.zhou Center for Quantum Materials and Devices College of PhysicsChongqing UniversityChongqing 401331China Key Laboratory of Artificial Micro-and Nano-Structures of Ministry of Education and School of Physics and TechnologyWuhan UniversityWuhan 430072China Chongqing Institute of Green and Intelligent Technology Chinese Academy of ScienceChongqing 400714China

Based on first-principles calculations and symmetry arguments,we reveal that the non-centrosymmetric ternary tetradymite BiSbTe_(3) possesses exotic dual topological features of Weyl semimetallic phases with z_(2) index(1:000).The results show that the helical Dirac-type surface states protected by the time-reversal symmetry are present in the vicinity of the Brillouin zone center,which is consistent with the experimental ***,we show that four pairs of Weyl points reside exactly at the Fermi level,which are guaranteed to be located on high-symmetry planes due to mirror *** helical surface states and the projected Weyl nodes are well separated in the momentum space,facilitating their observations in *** work not only uncovers a unique quantum phenomenon with dual topological features in the tetradymite family but also paves a fascinating avenue for exploring the coexistence of multi-topological states with wide applications.

关键词： metallic symmetry topological

Template-free Fabrication and Luminescent Characterization of highly Uniform and Monodisperse y_2O_2S:Sm^(3+) hollow Submicrospheres

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Journal of Materials Science & Technology 2012年第7期28卷 666-672页

作者： S.Q. Deng z.P. Xue y.h. yang Q. yang y.L. Liu Department of Chemistry Jinan University Guangzhou 510632 China

Well dispersed and homogeneous y2O2S：Sm3＋ hollow submicrospheres were successfully achieved by a template- free solvothermal method combining with a postcalcining process. The crystalstructure and particle morphology were investigated by the X-ray diffraction （XRD）, Fourier transform infrared （FT-IR） spectra, scanning and transmission electron microscopy （SEM and TEM）, respectively. A possible growth mechanism was proposed to reveal the formation process. Luminescence properties of the y202S：Sm3＋ long-lasting phosphor were an- alyzed by measuring the excitation spectra, emission spectra, afterglow decay curve and thermoluminescence curve. The excitation spectra indicated that the phosphor could be excited effectively by the ultraviolet-light emitting diode （UV-LED） or blue LED, and the emission spectra showed that the phosphor could emit red light from 600 to 650 nm.

关键词： yttrium oxysulfide hollow submicrosphere Luminescence Long-lasting phosphor