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RECRYSTALliZATION IN A SPINODAL Cu Ni Fe ALLOY

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Acta Metallurgica Sinica(English Letters) 1999年第4期12卷 322-326页

作者： hao, S.M. hao, x.J. Zhao, G. li, h.x. Northeastern Univ Shenyang China

The interaction of spinodal decomposition and recrystallization process, and the characteristic of recrystallization in Cu-Ni-Fe alloy aged at different temperatures after solution-treatment and cold rolling have been studied by structural analysis and Vickers hardness test. It has shown that the recrystallization of spinodal Cu -Ni-Fe alloy might be divided into 2 types: spinodal decomposition, recovery and recrystallization of two-phase microstructure take place in the deformed alloy aged below the spinodal temperature; while recrystallization of single-phase microstructure and growth of fully-recrystallized grains take place in the deformed alloy aged above the spinodal temperature. The deformed alloy aged below the spinodal temperature recrystallizes in cellular morphology.

关键词： Aging of materials Decomposition Iron alloys Metal melting Microstructure Morphology Nanotechnology Nickel alloys Permanent magnets Recrystallization (metallurgy)

ISOThERMAL SECTION OF Mg-Zn-La SYSTEM IN Mg RICh CORNER AT 350℃

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Acta Metallurgica Sinica(English Letters) 2008年第5期21卷 329-335页

作者： M.L. huang h.x. li h. Ding Y.P. Ren S.M. hao School of Materials and Metallurgy Northeastern University Shenyang 110004 China

Alloys of Mg-Zn-La system in Mg rich corner at 350℃ have been prepared in this study. Scanning electron microscopy （SEM）, electron probe microanalysis with energy dispersive x-ray spectroscopy （EPMA-EDS）, and x-ray diffraction （xRD） have been used to identify the phase equilibrium and the composition of each phase in the alloys. As a result, the isothermal section of Mg-Zn-La system in Mg rich corner at 350℃ has been determined. The result shows that, in addition to some binary phases, there exists a linear ternary compound called T-phase in Mg-Zn-La system at 350℃, in which the La content is about 8 at. pct ±0.4 at. pct and the Zn content is 8 at. pct- 48 at. pct. The T-phase has a C-centered orthorhombic crystal structure, and the lattice parameters are a=0.965-1.020 nm, b=1.121 1.142 nm, c=0.950-0.977 nm.

关键词： Mg-Zn-La system Phase equilibrium T-phase Isothermal section

Fast efficient photon deceleration in plasmas by using two laser pulses at different frequencies

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Matter and Radiation at Extremes 2024年第3期9卷 11-18页

作者： Y.x.Wang x.L.Zhu S.M.Weng P.li x.F.li h.Ai h.R.Pan Z.M.Sheng Key Laboratory for Laser Plasmas(moe) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center of IFSA Shanghai Jiao Tong UniversityShanghai 200240China Research Center of Laser Fusion of China Academy of Engineering Physics MianyangSichuan 621900China State key Laboratory of high Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Tsung-dao Lee Institute Shanghai Jiao Tong UniversityShanghai 200240China

The generation of ultrashort high-power light sources in the mid-infrared(mid-IR)to terahertz(Thz)range is of interest for applications in a number of fields,from fundamental research to biology and *** conventional laser technology,photon deceleration in plasma wakes provides an alternative approach to the generation of ultrashort mid-IR or Thz ***,we present a photon deceleration scheme for the efficient generation of ultrashort mid-IR or Thz pulses by using an intense driver laser pulse with a relatively short wavelength and a signal laser pulse with a relatively long *** signal pulse trails the driver pulse with an appropriate time delay such that it sits at the front of the second wake bubble that is driven by the driver *** to its relatively long wavelength,the signal pulse will be subjected to a large gradient of the refractive index in the plasma wake ***,the photon deceleration in the plasma wake becomes faster and more efficient for signal pulses with longer *** greatly enhances the capacity and efficiency of photon deceleration in the generation of ultrashort high-power light sources in the long-wavelength IR and Thz spectral ranges.

关键词： laser ultrashort photon

Reactive destabilization and bidirectional catalyzation for reversible hydrogen storage of liBh_(4) by novel waxberry-like nano-additive assembled from ultrafine Fe_(3)O_(4) particles

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Journal of Materials Science & Technology 2024年第6期173卷 63-71页

作者： S.Wang M.h.Wu Y.Y.Zhu Z.L.li Y.x.Yang Y.Z.li h.F.liu M.x.Gao Department of Material Science Shenzhen MSU-BIT UniversityShenzhen 518172China State Key Laboratory of Silicon and Advanced Semiconductor Materials&School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Institute of Resources Utilization and Rare Earth Development State Key Laboratory of Rare Metals Separation and Comprehensive UtilizationGuangdong Provincial Key Laboratory of Rare Earth Development and ApplicationGuangdong Academy of SciencesGuangzhou 510650China Institute of Science and Technology for New Energy Xi’an Technological UniversityXi’an 710021China National Supercomputing Center in Shenzhen Shenzhen 518055China

liBh_(4) containing 18.5 wt.%h_(2) is an attractive high-capacity hydrogen storage material,however,it suffers from high operation temperature and poor ***,a novel and low-cost bifunctional additive,waxberry-like Fe_(3)O_(4) secondary nanospheres assembled from ultrafine primary Fe_(3)O_(4) nanoparticles,is synthesized,which exhibits significant destabilization and bidirectional catalyzation towards(de)hydrogenation of liBh_(4).With an optimized addition of 30 wt.% waxberry-like Fe_(3)O_(4),the system initiated dehydrogenation below 100℃ and released a total of 8.1 wt.%h_(2) to 400℃.After 10 cycles,a capacity retention of 70% was achieved,greatly superior to previously reported oxides-modified *** destabilizing and catalyzing mechanisms of waxberry-like Fe_(3)O_(4) on liBh_(4) were systematically analyzed by phase and microstructural evolutions during dehydrogenation and hydrogenation cycling as well as density functional theory(DFT)*** present work provides new insights in developing advanced nano-additives with unique structural and multifunctional designs towards liBh4 hydrogen storage.

关键词： liBh_(4) hydrogen storage Waxberry-like Fe_(3)O_(4) Destabilization Catalysis

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

INFLUENCE OF COLD ROLliNG TEChNOLOGY ON TExTURE EVOLUTION OF IF STEEL

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Acta Metallurgica Sinica(English Letters) 2002年第3期15卷 312-316页

作者： J.x. li, x.h. liu and G.D. WangState Key Laboratory of Rolling & Automation, Northeastern University, Shenyang 110006, China Manuscript received 16 July 2001 in revised form 6 September 2001 Lab. of Rolling and Automat. Northeastern Univ. Shenyang 110006 China

Two kinds of cold rolling experiments, single cold rolling and double cold rolling, were carried out on one titanium stabilized interstitial free (IF) steel that has been warm rolled at ferrite temperature. The main aim was to investigate the evolution of rolling and annealing textures from the well known behavior observed under single cold rolling condition to the less understood double cold rolling by using orientation distribution function (ODF). In the twice cold rolled samples, the annealing texture comprises only single {111}(110-112) r-fibre texture when it subjected to moderate reduction in the first round of rolling. Accordingly both the once cold rolled sample and the twice cold rolled sample with heavy reduction in the first round of rolling have much complex texture components. They are related to the formation of initial {111} subgrain and the priority growth of stable {111} nucleus.

关键词： double rolling cold rolling reduction deformation texture annealing texture r-value

hard yet tough and self-lubricating(CuNiTiNbCr)C_(x) high-entropy nanocomposite films:Effects of carbon content on structure and properties

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Journal of Materials Science & Technology 2024年第6期173卷 20-30页

作者： Y.T.li x.M.Chen x.K.Zeng M.liu x.Jiang Y.x.Leng Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Key Laboratory of Noise and Vibration Research Institute of AcousticsChinese Academy of SciencesBeijing 100190China State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China School of Mechanical and Electrical Engineering Mianyang Teachers’CollegeMianyang 621000China

The single-phase high-entropy alloy film is difficult to meet severe friction conditions due to its low hardness and high friction ***-composite structure film is composed of at least two separated phases,showing the properties of strength and toughness integration and excellent wear *** design of nanocomposite structures can effectively improve the mechanical properties and tribological properties of high-entropy alloy *** this study,the(CuNiTiNbCr)C_(x) nanocomposite high-entropy films(hEFs)integrated with high hardness,high toughness,and self-lubrication were synthesized by the double-target co-sputtering *** effect of carbon content on microstructure,mechanical properties,and tribological properties of(CuNiTiNbCr)C_(x) films was *** the increase of carbon content in the hEFs,the carbon atoms preferentially react with Ti,Nb,and Cr to form a(TiNbCr)C ceramic-reinforced phase,and then the excess carbon atoms precipitate in the form of amorphous carbon(a-C)lubricating phase in the *** structure of the hEFs changes from an amorphous structure to a nanocomposite structure of amorphous(amorphous CuNiTiNbCr phase+a-C phase)/nanocrystalline(TiN-bCr)C *** the carbon content is about 21.2 at.%,the carbide phase in the film reaches saturation and the hardness and modulus of the films are highest,which are 18 GPa and 228 GPa,*** hEFs with a carbon content of 44.0 at.%show the best toughness and tribological properties with a friction coefficient of 0.16 and a wear rate of 2.4×10^(-6) mm^(3)/(N m),which is mainly attributed to the excellent resistance to fatigue crack growth and the interfacial lubricating layer formed in the friction *** nanocomposite(CuNiTiNbCr)C_(x) hEFs show very promising application prospect in the field of friction protection.

关键词： high-entropy films Nanocomposite Double-target co-sputtering Strengthening-toughening Tribological properties

Uncovering the hierarchical clusters in the heat-affected zone of an electron beam weldedα/βtitanium alloy joint

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Journal of Materials Science & Technology 2024年第7期174卷 120-132页

作者： C.xu x.h.Shao h.J.Yang M.Lv h.Q.liu x.L.Ma 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 Suzhou laboratory Suzhou 215028China Department of Mechanical Engineering Kyushu UniversityFukuoka 819-0395Japan Bay Area Center for Electron Microscopy Songshan Lake Materials LaboratoryDongguan 523808China

Using high-resolution transmission Kikuchi diffraction(TKD)and transmission electron microscopy(TEM),we examined the hierarchical clusters that form in situ in the heat-affected zone(hAZ),which are com-monly referred to as“ghost”structures,of bimodal titanium alloy Ti-5Al-2Sn-2Zr-4Mo-4Cr(wt%,TC17).The ghost structures are enriched with Al elements but poor in Mo and Cr compared to the surroundingβ*** results show that the ghost structure in middle-hAZ mainly consists ofα_(L)laths with a high-angle grain boundary,which exhibits the classic Burgers orientation relationship(BOR)with the host matrix,while it encircles theα_(P)grains in *** the ghost structure is evidenced to form via in-complete martensitic *** results further confirm that the ghost structure is composed ofαL and tinyβ_(L)laths with BOR,with the former being enriched with Al and poor with Cr and Mo,while the latter is the ***,twoα_(L)variant clusters with a check-mark morphology are fre-quently observed viewed along[0001]_(αL)//[110]_(βL)directions,which are dominated by the crystallographic and geometrical relationships betweenαandβ*** on the microstructural characterization,it is hypothesized that the ghost structure is transformed from the initialα_(P)phase,due to the coupling ef-fect of high thermal stress(which induces the formation of a large number of dislocations)and element diffusion caused by sudden temperature increase and plunge cooling in the hAZ during the welding pro-cess.

关键词： TC17 titanium alloy Electron beam welding(EBW) The ghost structure Transmission Kikuchi diffraction(TKD) Transmission electron microscopy(TEM)

Greatly enhanced corrosion/wear resistances of epoxy coating for Mg alloy through a synergistic effect between functionalized graphene and insulated blocking layer

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Journal of Magnesium and Alloys 2024年第1期12卷 332-344页

作者： Z.Y.xue x.J.li J.h.Chu M.M.li D.N.Zou L.B.Tong School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China

The poor corrosion and wear resistances of Mg alloys seriously limit their potential applications in various *** conventional epoxy coating easily forms many intrinsic defects during the solidification process,which cannot provide sufficient *** the current study,we design a double-layer epoxy composite coating on Mg alloy with enhanced anti-corrosion/wear properties,via the spin-assisted assembly *** outer layer is functionalized graphene(FG)in waterborne epoxy resin(WEP)and the inner layer is Ce-based conversion(Ce)*** FG sheets can be homogeneously dispersed within the epoxy matrix to fill the intrinsic defects and improve the barrier *** Ce film connects the outer layer with the substrate,showing the transition *** corrosion rate of Ce/WEP/FG composite coating is 2131 times lower than that of bare Mg alloy,and the wear rate is decreased by~90%.The improved corrosion resistance is attributed to the labyrinth effect(hindering the penetration of corrosive medium)and the obstruction of galvanic coupling *** synergistic effect derived from the FG sheet and blocking layer exhibits great potential in realizing the improvement of multi-functional integration,which will open up a new avenue for the development of novel composite protection coatings of Mg alloys.

关键词： Mg alloy Functionalized graphene Epoxy coating Corrosion/wear resistance Blocking layer