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Improving Intergranular stress Corrosion Cracking Resistance in a fe–18Cr–17Mn–2Mo–0.85n Austenitic stainless steel through Grain Boundary Character Distribution Optimization

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Acta Metallurgica sinica(English Letters) 2022年第11期35卷 1849-1861页

作者： f.shi L.Yan j.hu L.f.wang t.Z.li w.li X.j.Guan C.M.liu X.w.li Department of Materials Physics and Chemistry School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China state Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China Key Laboratory for Anisotropy and texture of Materials(Ministry of Education) Northeastern UniversityShenyang 110819China

the grain boundary character distribution(GBCD) optimization and its effect on the intergranular stress corrosion cracking(IGsCC) resistance in a cold-rolled and subsequently annealed fe-18 Cr-17 Mn-2 Mo-0.85 n high-nitrogen nickel-free austenitic stainless steel were systematically *** results show that stacking faults and planar slip bands appearing at the right amount of deformation(lower than 10%) are beneficial cold-rolled microstructures to the GBCD *** proportion of special boundaries gradually increases in the subsequent stages of recrystallization and grain growth,accompanying with the growth of twin-related domain in the experimental *** this way,the fraction of low ∑ coincidence site lattice(CsL) boundaries can reach as high as 82.85% for the specimen cold-rolled by 5% and then annealed at 1423 K for 72 *** GBCD optimization,low ∑ CsL boundaries and the special triple j.nctions(j2,j3) of high proportion can greatly hinder the nitride precipitation along grain boundaries and enhance the capability for intergranular crack arrest,thus improving the IGsCC resistance of the experimental steel.

关键词： High-nitrogen austenitic stainless steel Grain boundary character distribution Coincidence site lattice(CsL)grain boundary Electron backscatter diff raction(EBsD) Intergranular stress corrosion cracking

Applicability of large-ion lithophile and high field strength element basalt discrimination diagrams

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International journal of Digital Earth 2018年第7期11卷 752-760页

作者： X.L.liu Q.Zhang w.C.li f.C.Yang Y.Zhao Z.li s.t.jiao j.R.wang n.Zhang s.s.wang w.f.Chen Z.j.Pan j.Yang X.L.Du faculty of Land and Resource Engineering Kunming University of Science and TechnologyKunmingPeople’s Republic of China Institute of Geology and Geophysics Chinese Academy of SciencesBeijingPeople’s Republic of China Chengdu Geological survey Center of China Geological survey ChengduPeople’s Republic of China school of Earth science Lanzhou UniversityLanzhouPeople’s Republic of China

Basalt discriminant diagrams have been used to ident.f. the tectonic setting of basaltic magmatism since the 1970s and have played an important role in reconstructing paleotectonic ***,the significant increase in the availability of geochemical data has led to a reassessment of these diagrams,suggesting that some of the tectonic settings indicated by these diagrams are not ***,we use a database of global ocean island basalt(OIB),mid-ocean ridge basalt(MORB),and island arc basalt(IAB)geochemistry to propose a series of new tectonic discriminant diagrams based on the ratios of large-ion lithophile elements(liLEs)to high field strength elements(HfsEs).these new diagrams indicate that the liLE can be used to differentiate OIB,MORB,and IAB samples,meaning that liLE/HfsE ratios can discriminate between these basalts that.f.rm in different tectonic *** new diagrams can correctly assign samples to OIB,MORB,and IAB categories more than 85%of the time,with the discrimination between OIB and MORB having an accuracy of slightly less than 85%.

关键词： Basalt liLE HfsE discrimination diagram geochemistry

Low-loss silicon core fibre platform for mid-infrared nonlinear photonics

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light(science & Applications) 2019年第1期8卷 202-211页

作者： Haonan Ren li shen Antoine f.j.Runge thomas w.Hawkins john Ballato Ursula Gibson Anna C.Peacock Optoelectronics Research Centre University of SouthamptonSouthampton SO171BJUK wuhan national Laboratory for Optoelectronics(wnLO) Huazhong University of Science and Technology430074 WuhanChina Department of Materials science and Engineering Clemson UniversityClemsonSC 29634USA Department of Physics Norwegian University of Science and Technology(NTNU)N-7491 TrondheimNorway Department of Applied Physics KTH Royal Institute of Technology10044 StockholmSweden the Institute of Photonics and Optical science(IPOs) School of PhysicsUniversity of SydneySydneyNSW 2006Australia

Broadband mid-infrared light sources are highly desired for wide-ranging applications that span free-space communications to *** recent years,silicon has attracted great interest as a platform for nonlinear optical wavelength conversion in this region,owing to its low losses(linear and nonlinear)and high ***,most research in this area has made use of small core waveguides fabricated from silicon-on-insulator platforms,which suffer from high absorption losses of the use of silica cladding,limiting their ability to generate light beyond 3μ***,we design and demonstrate a compact silicon core,silica-clad waveguide platform that has low losses across the entire silicon transparency *** waveguides are fabricated from a silicon core fibre that is tapered to engineer mode properties to ensure efficient nonlinear propagation in the core with minimal interaction of the mid-infrared light with the *** waveguides exhibit many of the benefits of fibre platforms,such as a high coupling efficiency and power handling capability,allowing for the generation of mid-infrared supercontinuum spectra with high brightness and coherence spanning almost two octaves(1.6-5.3μm).

关键词： waveguide fibre nonlinear

High strength-superplasticity combination of ultrafine-grained ferritic steel:the significant role of nanoscale carbides

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journal of Materials science & technology 2021年第24期83卷 131-144页

作者： j.w.liang Y.f.shen R.D.K.Misra P.K.liaw Key Laboratory for Anisotropy and texture of Materials(MOE) School of Materials Science and EngineeringNortheastern UniversityShenyang110004China the state Key Lab of Rolling&Automation Northeastern UniversityShenyang110819China Laboratory for Excellence in Advanced steel Research University of Texas at El PasoTX79968USA Department of Materials science and Engineering University of TennesseeKnoxvilleTN37996USA

there is currently a gap in our understanding of mechanisms that contribute to high strength and high plasticity in high strength UfG ferritic steel with nano-size fe3 C carbides in situations that involve combination of various strain rates and high *** this regard,we describe the mechanistic basis of obtaining high strength-high plasticity combination in an ultrafine-grained(UfG)(~500±30 nm)ferritic steel with nano-size carbides,which sustained large plastic deformation,exceeding 100%elongation at a temperature significantly below 0.5 of the absolute melting point(tm).to address the missing gap in our knowledge,we conducted a series of experiments involving combination of strain rate and temperature effects in conj.nction with electron microscopy and atom probe tomography(APt).strain rate studies were carried out at strain rates in the range of 0.0017-0.17 s^(-1)and at different temperatures from 25℃to 600℃.Dynamic recrystallization occurred at 600℃,resulting in a significant decrease in yield and tensile ***,the UfG ferritic steels had an advantage in tensile strength(Uts)and elongation-to-failure(εf)at 600℃,especially at strain rate of 0.0017 s^(-1),with high Utsof 510 MPa and excellent low temperature(tm)superplasticity(εf=110%).these mechanical properties are significantly superior compared to similar type of steels at identical temperature.A mechanistic understanding of mechanical behavior of UfG ferritic steels is presented by combining the effect of strain rate,temperature,and nano-size carbides.

关键词： UfG ferritic steel strain rate temperature nano-size precipitate Low temperature superplasticity

A pathway to improve low-cycle fatigue life of face-centered cubic metals via grain boundary engineering

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journal of Materials science & technology 2022年第18期113卷 82-89页

作者： X.j.Guan Z.P.jia s.M.liang f.shi X.w.li Department of Materials Physics and Chemistry School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China state Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China Key Laboratory for Anisotropy and texture of Materials Ministry of EducationNortheastern UniversityShenyang 110819China

to probe a pathway to improve the low-cycle fatigue life of face-centered cubic(fCC)metals via grain boundary engineering(GBE),the tension-tension fatigue tests were carried out on the non-GBE and GBE Cu-16 at.%Al alloys at relatively high stress *** results indicate that the cyclic strain localiza-tion and cracking at grain boundaries(GBs)can be effectively suppressed,especially at increased stress amplitude,by an appropriate GBE treatment that can result in a higher resistance to GB cracking and a greater capability of compatible ***,the sensitivity of fatigue life to stress amplitude can be weakened by GBE,and the low-cycle fatigue life of Cu-16 at.%Al alloys is thus distinctly improved.

关键词： Cu-Al alloy Grain boundary engineering fatigue life Crack nucleation stress amplitude

sYntHEsIs AnD MICROstRUCtURE Of sUPERHARD tin/sin_x MULtILAYER tHIn fILMs

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Acta Metallurgica sinica(English Letters) 2005年第3期18卷 242-248页

作者： Z.f.Zhou Y.G.shen Y.w.Mai K.Y.li AdvancedCoatingsAppliedResearchLaboratory（ACARL） DepartmentofManufacturingEngineeringandEngineeringManagementCityUniversityofHongKongKowloonHongKongChina CentreforAdvancedMaterialstechnology（CAMt） SchoolofAerospaceMechanicalandElectronicEngineeringUniversityofSydneySydneyNSW2006Australia

Multilayer thin films of tin/sinx have been deposited onto heated si 100 substra tes (200℃) by reactive dc-magnetron sputtering from ti and si targets in an Ar- n2 gas mixture. the rotation speed of the substrate holder w.s.varied from 1 to 20rpm, while target currents were held constant, to produce bilayer periods vary ing from approximately 22 to 0.6nm. these multilayer films were characterized by atomic force microscopy (AfM), cross-sectional transmission electron microscopy (tEM), scanning electron microscopy (sEM), and microhardness measurements. tEM and sEM studies showed elimination of columnar structure in tin, owing to the in corporation of amorphous sinx layers. the crystallinity of tin and amorphous nat ure of sinx were confirmed by high resolution tEM. An optimum rotation speed w.s.observed, at which hardness w.s.a maximum. the resulting bilayer period w.s.fou nd to be approximately 1.6nm, which resulted in a significant improvement in mic rohardness (~57GPa). the rms surface roughness for this film w.s.less than 1.5nm .

关键词： multilayers hardness supermodulu s stress tin/sinx

tRIBOLOGICAL AnD HIGH sPEED tURnInG PERfORMAnCE In ti_(1-x)Al_(x)n COAtInGs PREPARED BY CLOsE-fIELD UnBALAnCED MAGnEtROn sPUttERInG

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Acta Metallurgica sinica(English Letters) 2005年第3期18卷 254-260页

作者： P.w.s.um M.Escursell t.H.wong K.Y.li Z.f.Zhou Y.G.shen Advanced Coatings Applied Research Laboratory(ACARL) Department of Manufacturi ng Engineering and Engineering ManagementCity University of Hong KongKowloonHong KongChina

titanium-aluminium-nitride(ti_(1-x)Al_(x)n)coatings were deposited by close-field un balanced magnetron sputtering on M42 steel substrates and wC-6wt%Co inserts at 450℃.the tribological behavior w.s.analyzed by sliding against steel and wC-6wt%Co balls,while the turning performance w.s.evaluated by a conventional tu rning machine at high cutting speeds without using *** the tribological tests,the formation of transfer layer and the variations of hardness of the co atings played an important role for sliding against steel *** the coating s sliding against wC-6wt%Co balls,the ti-Al-n coatings showed a similar frictio n coefficient,but the tin coating exhibited a lower *** difference could be explained by the tri-oxidation wear *** the turning tests,a super ior cutting performance of the coating w.s.found at x=0.45,which endured 38 min utes before the tool flank wear reached the maximum value of 0.3mm,whereas only 20 minutes were endured for the tin *** excellent performance of the c oatings in the turning tests could be explained by the enhanced mechanical prope rties and oxidation/diffusion resistance of the coatings.

关键词： hardness ti-Al-n coating tribology turning test wear test

Black locust coppice stands homogenize soil diazotrophic communities by reducing soil net nitrogen mineralization

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forest Ecosystems 2022年第3期9卷 289-300页

作者： Kun li huimei tian w.Keith Moser steven t.Overby L.scott Baggett Ruiqiang ni Chuanrong li weixing shen Mountain tai forest Ecosystem Research station of state forestry Administration Key Laboratory of State Forestry Administration for Silviculture of the Lower Yellow RiverForestry College of Shandong Agricultural UniversityTai'an271018ShandongChina Rocky Mountain Research station United States Forest Service2500 S.Pine Knoll Dr.FlagstaffAZ86001USA Rocky Mountain Research station United States Forest Service240 West Prospect Fort CollinsCO80526USA Mount tai scenic spot Management Committee Tai'an271000ShandongChina

Background:Black locust(BL,Robinia pseudoacacia)is considered a promising tree species for reforestation due to its great ability to fix ***,after two or three coppice-harvesting rotations,the productivity of BL *** soil microbial communities are affected and how these groups correlate with the nitrogen mineralization process across multi-generation stands remains ***:we investigated the composition and structure of free-living nitrogen-fixing microorganisms(diazotrophs)by sequencing the marker gene nifH and compared these results to levels of soil nitrogen mineralization in the bulk soil and rhizosphere in black locust plantations on Mount tai,***:the results showed multi-generation BL coppice plantations decreased the total soil nitrogen(n),soil phosphorus(P),soil microbial biomass n(MBn),soil microbial biomass C(MBC),soil nitrification rate(Rn),soil ammonification rate(Ra),and net soil n mineralization rate(Rm),but significantly increased the concentration of soil nH_(4þ)-n to maintain sufficient nO_(3)^(-)*** dominant species in bulk soil and rhizosphere changed from Rhodopseudomonas(22.62%and 15.76%),unclassified_c_Alphaproteobacteria(22.37%and 29.28%),unclassified_o_Rhizobiales(15.40%and 13.31%),Bradyrhizobium(12.00%and 11.74%)in seedling plantations to Bradyrhizobium(45.95%and 47.86%)and Rhodopseudomonas(43.56%and 41.84%)in coppice plantations,*** test and Redundancy analysis(RDA)revealed that Rn,Ra,and Rm were the most important.f.ctors shaping the diazotrophic ***:Our results suggest that the multi-generation BL coppice plantation can homogenize soil diazotrophic communities,which is mainly regulated by the available n loss caused by nitrogen *** the management technology of coppice plantations will provide more beneficial external consumption.

关键词： Black locust plantation nifH gene nitrogen mineralization Coppice soil nutrient

On three Differential Equations Associated with Chebyshev Polynomials of Degrees 3,4 and 6

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Acta Mathematica sinica,English series 2017年第1期33卷 21-36页

作者： li Chien shen Department of Mathematics University of Florida Gainesville FL 32611-8105

we shall study the differential equation y^l2=tn（y）-（1-2μ2）;where μ2 is a constant, tn（x） are the Chebyshev polynomials with n = 3,4,6. the solutions of the differential equations will be expressed explicitly in terms of the weierstrass elliptic function which can be used to construct theories of elliptic functions based on 2f1 （1/4, 3/4; 1; z）, 2f1 （l/3, 2/3; 1; z）, 2f1 （1/6, 5/6; 1; z） and provide a unified approach to a set of identities of Rmanuj.n involving these hypergeometric functions.

关键词： Chebyshev polynomials Eisenstein series jacobi theta functions weierstrass ellipticfunction