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Acta Metallurgica Sinica(English letters) 2005年第4期18卷 533-538页

作者： y.l. yang C.S. liu F.J. Sun D. Zhang College of Science Northeastern University Shenyang 110004 China College of Material ＆ Metallurgy Northeastern University Shenyang 110004China

CW-CO2 laser nitriding technique was applied to improve the properties （such as aging property and the core loss） of grain oriented silicon steel. The samples were nitrided with regular space. laser power density and scanning speed were chosen as 7.8×10^5W·cm^-2 and 100mm·min^-1. By some laser irradiation, Fe4N and Fe3N were formed in the nitrided zone. The nitrided samples were annealed at the temperatures ranged from 100 to 90℃. The core loss of some interested samples was tested. The results show that the core loss of the nitrided samples with different thickness of 0.23 and 0.30mm decreased by 14.9% and 9.4% respectively, and the aging property were improved up to 800℃. The mechanism of laser nitriding to improve the properties of grain oriented silicon steel is discussed.

关键词： laser nitriding grain oriented silicon steel sheet core loss aging property

IMPROVING THE SURFACE PROPERTy OF TC4 AllOy By.l.SER NITRIDING AND ITS MECHANISM

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Acta Metallurgica Sinica(English letters) 2006年第2期19卷 151-156页

作者： y.l. yang G.J. Zhao D. Zhang C.S. liu Gollege of Sdence Northeastern University Shenyang 110004 Ghina College of Material and Metallurgy Northeastern University Shenya g 110004 China

The mixing technology of laser and heated nitrogen was applied to improve the surface hardness of titanium alloy （ TC4 ）. The samples were nitrided with laser power density of 6.S × 10^6SW. cm^-2, the scanning speed varioas from 100 to 500mm ·min^-1. The nitrogen gas was pre-heated to 300℃ to accelerate the nitriding process. Some interested samples were tested with XRD method （X-ray diffraction） to analyze the composition of nitrides, and the surface hardness of HV was measured. The results show that TiN and Ti2N were formed on the surface of Ti alloy with proper nitriding parameters, but TiN is the main composition. The surface hardness increased by three times, which is from the original value of 269to 794kg·mm^-2. The mechanism of the mixing technology is considered mainly of the activation of nitrogen by.l.ser power and the pre-heated process which accelerated the nitriding process. The nitridation process can be considered as six steps given in detail. The result by analyzing the mechanism of improving the surface property of TiAl alloy shows the improvement of surface property due to two factors： the first reason is the result of laser annealing, and the second one is the formation of TiN.

关键词： laser nitridation surface property Ti alloy

lASER ClADDED TiCN COATINGS ON THE SURFACE OF TITANIUM

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Acta Metallurgica Sinica(English letters) 2007年第3期20卷 210-216页

作者： y.l. yang D. Zhang H.S. Kou C. S. liu College of Science Northeastern University Shenyang 110004 China College of Material and Metallurgy Northeastern University Shenyang 110004 China

laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs （OM）. The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm/s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm^-2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2 and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80μm, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.

关键词： laser cladding TiCN coating titanium

Spalling characteristics of high-temperature treated granitic rock at different strain rates

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1280-1288页

作者： l.F.Fan Q.H.yang X.l.Du The Key.l.boratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing100124China

The dynamic spalling characteristics of rock are important for stability analysis in rock *** paper presented an experimental investigation on the dynamic spalling characteristics of granite with different temperatures and strain rates.A series of dynamic spalling tests with different impact velocities were conducted on thermally treated granite at different *** dynamic spalling strengths of granite with different temperatures and strain rates were determined.A model was proposed to correlate the dynamic spalling strength of granite,high temperature and strain *** results show that the spalling strength of granite decreases with increasing ***,the spalling strength of granite with a higher strain rate is larger than that with a lower strain *** proposed model can describe the relationship among dynamic spalling strength of granite,high temperature and strain rate.

关键词： Dynamic spalling characteristics High temperature Strain rate Dynamic loading Granite

Application of Gaussian Beam Summation Migration in Reflected In-seam Wave Imaging

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Acta Geologica Sinica(English Edition) 2024年第1期98卷 276-284页

作者： HAN Jianguang lÜQingtian ZHANG Zhiheng yang Shun WANG Shuo Chinese Academy of Geological Sciences Beijing 100037China Shandong Taishan Resources Exploration Co. Ltd.Jinan 250104China

The geological conditions for coal mining in China are complex,with various structural issues such as faults and collapsed columns seriously compromising the safety of coal mine ***-seam wave exploration is an effective technique for acquiring detailed information on geological structures in coal seam working ***,the existing reflected in-seam wave imaging technique can no longer meet the exploration precision requirements,making it imperative to develop a new reflected in-seam wave imaging *** study applies the Gaussian beam summation(GBS)migration method to imaging coal seams'reflected in-seam wave ***,with regard to the characteristics of the reflected in-seam wave data,methods such as wavefield removal and enveloped superposition are employed for the corresponding wavefield separation,wave train compression and other processing of reflected in-seam ***,imaging is performed using the GBS migration *** feasibility and effectiveness of the proposed method for reflected in-seam wave imaging are validated by conducting GBS migration tests on 3D coal-seam fault models with different dip angles and *** applying the method to reflected in-seam wave data for an actual coal seam working face,accurate imaging of a fault structure is obtained,thereby validating its practicality.

关键词： reflected in-seam wave Gaussian beam summation migration numerical tests fault

Deep bed filtration model for cake filtration and erosion

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 355-372页

作者： l.I.KUZMINA y.V.OSIPOV A.R.PESTEREV Department of Applied Mathematics HSE UniversityMoscow 101000Russia Department of Computer Science and Applied Mathematics Moscow State University of Civil EngineeringMoscow 129337Russia

Many phenomena in nature and technology are associated with the filtration of suspensions and colloids in porous media. Two main types of particle deposition,namely, cake filtration at the inlet and deep bed filtration throughout the entire porous medium, are studied by different models. A unified approach for the transport and deposition of particles based on the deep bed filtration model is proposed. A variable suspension flow rate, proportional to the number of free pores at the inlet of the porous medium, is considered. To model cake filtration, this flow rate is introduced into the mass balance equation of deep bed filtration. For the cake filtration without deposit erosion,the suspension flow rate decreases to zero, and the suspension does not penetrate deep into the porous medium. In the case of the cake filtration with erosion, the suspension flow rate is nonzero, and the deposit is distributed throughout the entire porous medium. An exact solution is obtained for a constant filtration function. The method of characteristics is used to construct the asymptotics of the concentration front of suspended and retained particles for a filtration function in a general form. Explicit formulae are obtained for a linear filtration function. The properties of these solutions are studied in detail.

关键词： deep bed filtration cake filtration porous medium particle deposition and erosion analytical solution concentration front

Effect of Heat Treatment on Microstructure and Mechanical Behavior of Cu-Bearing 316l Stainless Steel Produced by Selective laser Melting

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Acta Metallurgica Sinica(English letters) 2024年第1期37卷 169-180页

作者： Huan yang ying liu Jianbo Jin Kunmao li Junjie yang lingjian Meng Chunbo li Wencai Zhang Shengfeng Zhou Sino-German College of Intelligent Manufacturing Shenzhen Technology UniversityShenzhen518118China Institute of Advanced Wear and Corrosion Resistance and Functional Materials Jinan UniversityGuangzhou510632China Department of Orthopedics First Affiliated Hospital of Jinan UniversityGuangzhou510632China

Cu-bearing stainless steels(SSs)with high strength,excellent plasticity,and effective antimicrobial properties hold significant potential for applications in the marine *** this study,Cu-bearing SSs with copper ranging from 0 to 6.0 wt%were successfully prepared using selective laser melting(SlM)*** the Cu-bearing SSs with different copper contents,the effect of heat treatment on the microstructural and mechanical behaviors was studied *** observations revealed that the subgrain size of Cu-bearing SSs increased with heat treatment at 500℃ and 700℃ for 6 ***,the tensile strength and elongation increased after the heat treatment temperature due to the combined effect of dislocations,twins,andε-Cu precipitated ***,after heat treatment at 700℃,the SlM4.5Cu sample exhibited an abnormal rise in tensile strength and *** finding suggests that the diffusion strengthening caused byε-Cu precipitates exceeded the stacking fault ***,the tensile strength and elongation reached 693.32 MPa and 56.94%,*** work provides an efficient approach for preparing Cu-bearing SSs with exceptional strength and plasticity.

关键词： Selective laser melting Cu-bearing stainless steel(SS) Heat treatment Mechanical properties

轴重和频率对激光修复316l不锈钢涂层在铁路车轮踏面制动中摩擦学性能的影响

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表面工程与再制造 2024年第2期24卷 51-52页

作者： li S. Xiao Q. yang W. yang C. Wang y. State Key.l.boratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong University Nanchang 330013 China School of Mechatronics and Vehicle Engineering East China Jiaotong University Nanchang 330013 China Railway Industry Key.l.boratory of Intelligent Operation and Maintenance of Rolling Stock East China Jiaotong University Nanchang 330013 China

研究复杂制动环境对修复熔覆层服役性能的影响,对提高列车轮轨系统抵御极端恶劣环境的能力具有重要意义。本文针对火车车轮踏面局部损伤问题,利用激光熔覆修复技术在损伤处制备316l不锈钢涂层。采用MS-HT1000高温磨损试验机进行磨损实... 详细信息

研究复杂制动环境对修复熔覆层服役性能的影响,对提高列车轮轨系统抵御极端恶劣环境的能力具有重要意义。本文针对火车车轮踏面局部损伤问题,利用激光熔覆修复技术在损伤处制备316l不锈钢涂层。采用MS-HT1000高温磨损试验机进行磨损实验。然后,分析不同制动条件对修复试样在室温和高温下摩擦磨损性能的影响。

关键词：激光修复铁路车轮局部损伤磨损实验车轮踏面磨损试验机服役性能踏面制动

Effect of radiative loss mechanisms on FIR thermometric parameters of Nd^(3+)-doped lithium tellurite glasses

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Journal of Rare Earths 2024年第7期42卷 1250-1257,I0002页

作者： C.y.Morassuti A.P.l Silva l.A.O.Nunes S.M.lima l.H.C.Andrade Optical and Photothermal Spectroscopy Group(GEOF) Center for Studies in Natural Resources(CERNA)State University of Mato Grosso do Sul(UEMS)C.P.351DouradosMSBrazil Renato Archer Information Technology Center Dom Pedro I Highway(SP-65)Km 1436-Chácaras Campos dos AmaraisCampinasSPBrazil Institute of Physics of São Carlos University of São PauloSão CarlosSPBrazil

Nd^(3+)-doped tellurite glasses are promising materials for thermometers based on the fluorescence intensity ratio(FIR)***,at high Nd^(3+)concentrations,energy transfer(ET)processes such as optical reabsorption and cross-relaxation can affect the Nd^(3+)emission,which has been little explored in the ***,the present work investigated the use of Nd^(3+)-doped tellurite glass(samples doped with Nd^(3+)at 0.2 mol%,0.5 mol%,2.0 mol%,and 4.0 mol%)in fluorescence thermometers,in the temperature range from 299 to 371 *** results indicate a strong dependence of the FIR parameters on the Nd^(3+)concentration,due to changes in the emission band profiles caused by optical reabsorption of the Nd^(3+)emissions and cross-relaxation processes.A decrease of the relative sensitivity of the ratio^(4)F_(5/2)→^(4)I_(9/2)/^(4)F_(3/2)→^(4)I_(9/2)is observed for samples doped with higher amounts of Nd^(3+).The maximum relative sensitivity at 299 K is 3.00%/K,which is the highest value among the reported Nd^(3+)ions.

关键词： Nd^(3+)-doped tellurite glass Fluorescence intensity ratio Optical thermometry Judd-Ofelt Rare earths

High-efficiency Carbonation Modification Methods of Recy.l.d Coarse Aggregates

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 386-398页

作者：张美香 yang Xiaolin 丁亚红 SUN Bo ZHANG Xianggang lÜXiuwen Department of Civil Engineering Henan Polytechnic UniversityJiaozuo 454150China College of Architectural Engineering Xinyu UniversityXinyu 336500China

To solve the problem of only surface carbonation and realize high-efficiency carbonation of recy.l.d coarse aggregate,the method of carbonated recy.l.d coarse aggregate with nano materials pre-soaking was first put *** carbonation effect of modified recy.l.d coarse aggregate with three different carbonation methods was evaluated,and water absorption,apparent density and crush index of modified recy.l.d coarse aggregate were *** with XRD,SEM,and MIP microscopic analysis,the high-efficiency carbonation strengthening mechanism of modified recy.l.d coarse aggregate was *** experimental results show that,compared with the non-carbonated recy.l.d coarse aggregate,the physical and microscopic properties of carbonated recy.l.d coarse aggregate are *** method of carbonation with nano-SiO_(2) pre-soaking can realize the high-efficiency carbonation of recy.l.d coarse aggregate,for modified recy.l.d coarse aggregate with the method,water absorption is reduced by 23.03%,porosity is reduced by 44.06%,and the average pore diameter is 21.82 *** high-efficiency carbonation strengthening mechanism show that the pre-socked nano-SiO_(2) is bound to the hydration product Ca(OH)_(2) of the old mortar with nano-scale C-S-H,which can improve the CO_(2) absorption rate,accelerate the carbonation reaction,generate more stable CaCO_(3) and nano-scale silica gel,and bond to the dense three-dimensional network structure to realize the bidirectional enhancement of nano-materials and pressurized *** is concluded that the method of carbonation with nano-SiO_(2) pre-soaking is a novel high-efficiency carbonation modification of recy.l.d coarse aggregate.

关键词： recy.l.d coarse aggregate pressurized carbonation high-efficiency carbonation nano-SiO2 strengthening mechanism