检索结果-南通市图书馆

Hardness-thermal stability synergy in nanograined Ni and Ni alloys:Superposition of nanotwin and low-energy columnar boundary

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第6期137卷 123-131页

作者： F.H.Duan Y.lin q.li J.H.Luan J.Lu J.Pan Y.li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Laboratory of Nanomaterials&Nanomechanics Department of Mechanical EngineeringCity University of Hong KongHong KongChina State Key Laboratory of Material Processing and Die&Mould Technology and School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Department of Materials Science and Engineering City University of Hong KongHong KongChina Centre for Advanced Structural Materials Greater Bay Joint DivisionShenyang National Laboratory for Materials ScienceCity University of Hong Kong Shenzhen Research InstituteShenzhen 518057China City U-Shenzhen Futian Research Institute Shenzhen 518045China

Refining grains into nanoscale can significantly strengthen and harden metallic materials;however,nanograined metals generally exhibit low thermal stability,hindering their practical applications.In this work,we exploit the superposition of the contribution of nanotwins,low-angle grain boundaries,and microalloying to tailor superior combinations of high hardness and good thermal stability in Ni and Ni alloys.For the nanotwinned Ni having a twin thickness of∼2.9 nm and grain size of 28 nm,it exhibits a hardness over 8.0 GPa and an onset coarsening temperature of 623 K,both of which are well above those of nanograined Ni.Re/Mo microalloying can further improve the onset coarsening temperature to 773 K without comprising hardness.Our analyses reveal that high hardness is achieved via strengthen-ing offered by extremely fine nanotwins.Meanwhile,the superior thermal stability is mainly ascribed to the low driving force for grain growth induced by the low-angle columnar boundary architecture and to the additional pinning effect on the migration of twin/columnar boundaries provided by minor Re/Mo solutes.The present work not only reveals a family of nanotwinned metals possessing the combination of ultra-high hardness and high thermal stability but also provides a strategy for tailoring properties of metallic materials by pairing low-angle grain boundaries and twin boundaries.

关键词： Nanotwin Thermal stability Hardness Low-angle grain boundary Microalloying

DYNAMIC MODEL AND SIMULATION OF EAF STEELMAKING PROCESS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2003年第3期16卷 197-203页

作者： q.li X.Hong Shanghai Enhanced Laboratory of Ferrometallurgy Shanghai University Shanghai 200072 ChinaShanghai Enhanced Laboratory of Ferrometallurgy Shanghai University Shanghai 200072 China

Based on mass and energy balances and theories of thermodynamics and kinetics, a dynamic model in conjunction with relative operation parameters was derived. With this model, the EAF process in later stage of scarp melting was dynamically described, including time dependent variations of bath temperature, slag quantity, compositions of steel, slag and off-gas, etc. Steelmaking process in a domestic 100 ton UHP AC EAF was chosen as a computational example, and the simulated variations of temperature of hot metal and element contents was shown consistent with the actual process measurements within average error scopes of |△T| <15K, |[△A%C]| ≤ 0.036, |[△%Si]|≤0.00027, |[△%Mn]|≤0.002, |[△%P]|≤0.00089 and |[△%S]|≤0.001 respectively at the test points. The model will be extended to predict the whole production process including scrap melting procedure and evaluate its energy and material consumption, the production efficiency, etc., which will provide assistance for the improvement of EAF operation and control.

关键词： EAF dynamic model simulation

MICROSTRVCTURE SIMULATION AND PROCESS OPTIMIZATION OF TURBINE BLADE CASTINGS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1998年第5期11卷 383-390页

作者： D.Z.li Z.Y.Hu q.li Y.Y.li Inst of Metal Research The Chinese Acad of Sciences Shenyang China

The probabilistic modeling is applied to calculate microstructural features of the thin complex smprolloy turbine blades cast by the vacuum investment process. The random distribution, orientation and physical mechanism of the nucleation, the growth kinetics of dendrites and the columnar-to-equiaxed transition (CET) are considered.Capitalizing on these simulating schemes, the comprehensive influence of key process variables on the scale and uniformity of grains has been involved quantitatively. The validity of the modeling is confirmed by selection of the optimum process variables.

关键词： Probabilistic modeling microstructure process optimization

18F-FDG PET/CT在非小细胞肺癌新辅助化疗免疫治疗后纵隔淋巴结病变评估中的临床应用

在线全文

学校读者我要写书评

暂无评论

国际医学放射学杂志 2024年第1期 129-129页

作者： L.Zhang H.R.E J.Huang J.q.Wu q.li L.K.Hou 刘莹莹

摘要目的 PET/CT在非小细胞肺癌（NSCLC）新辅助化疗免疫治疗后预测ypN2病变的表现尚未见报道。该多中心研究分析了PET/CT在评估这些病人ypN2病变中的作用。方

关键词：

Misorientation dependent thermal condition-solute field cooperative effect on competitive grain growth in the converging case during directional solidification of a nickel-base superalloy

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第1期96卷 151-159页

作者： X.B.Meng J.G.li C.N.Jing J.D.liu S.Y.Ma J.J.liang C.W.Zhang M.Wang B.T.Tang T.lin J.L.Chen X.L.Zhang q.li School of Mechanical and Automotive Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China Institute of Metal Research Chinese Academy of SciencesShenyang110016China School of Materials Science and Engineering Shandong Jianzhu UniversityJinan 250014China AECC Shenyang liming Aero-Engine Co. LTD.Shenyang110043China College of Material Science and Engineering North Minzu UniversityYinchuan 750021China Faculty of electro-mechanical information Weifang University of Science and TechnologyShouguang262700China

Nowadays,thermal condition and solute field are considered as the potential dominant factors controlling competitive grain growth during directional solidification process.However,the controlling modes and critical conditions of competitive grain growth have been drastically debated over the past two decades.In this work,thermal condition and solute field are combined to study the competitive grain growth in the converging case by experimental observation and numerical simulation of bicrystal samples.We find the competitive grain growth is controlled by the cooperative effect of thermal condition and solute field,and the controlling modes are related to the bicrystal misorientation between favorably and unfavorably oriented grains.When the unfavorably oriented grain is low misoriented,unfavorably oriented grain dominates grain selection,and the competitive grain growth performs as solute field domination.However,with the increase of unfavorably oriented grain’s misorientation,the grain selection converts into favorably oriented grain domination,and the competitive grain growth changes to thermal condition domination.To explain these abnormal transformation phenomena,we propose a misorientation dependent thermal condition-solute field cooperative domination model and identify the critical conditions by a critical misorientation(θ_(cm)).According to dynamic equation of dendrite growth,we calculate the critical misorientationθ;to prove this model.The theoretical calculation results agree well with the experimental results.

关键词： Competitive grain growth Cooperative effect Thermal condition Solute field Critical misorientation Unusual overgrowth Abnormal transformation

On the texture evolution of Mg-Zn-Ca alloy with different hot rolling paths

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2017年第2期5卷 166-172页

作者： q.li G.J.Huang X.D.Huang S.W.Pan C.L.Tan q.liu College of Materials Science and Engineering Chongqing UniversityChongqing 400044China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

In the present study,the texture evolution and mechanical anisotropy in a typical Mg–Zn–Ca alloy through hot cross rolling(CR)and unidirectional rolling(UR)were systematically studied.The results show that the rolling path greatly affects the annealed texture.The UR develops a texture with basal poles mainly distributing along the transverse direction(TD).By contrast,an ellipse-like(0002)texture with basal pole inclining largely away from the normal direction(ND)is developed after hot cross rolling and annealing.Therefore,the CR is an effective method to tailor the texture of the experimental alloy.Unfortunately,this ellipse-like texture could not reserve during the subsequent unidirectional hot rolling and annealing.Both UR and CR plates exhibit a strong planar mechanical anisotropy compared with the traditional unidirectional rolled plate.

关键词： Mg alloys Hot cross rolling Texture Mechanical anisotropy

Laboratory study of fracture initiation and propagation in Barre granite under fluid pressure at stress state close to failure

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2023年第3期15卷 538-550页

作者： Bing q.li Michela Casanova Herbert H.Einstein Department of Civil and Environmental Engineering Massachusetts Institute of TechnologyCambridgeUSA Department of Civil and Environmental Engineering Western UniversityLondonCanada School of Architecture Civil and Environmental EngineeringÉcole Polytechnique Fédérale de LausanneLausanneSwitzerland

Hydraulic fracturing is frequently used to increase the permeability of rock formations in energy extraction scenarios such as unconventional oil and gas extraction and enhanced geothermal systems(EGSs).The present study addresses uncertainties in the hydraulic fracturing process pertaining to EGSs in crystalline rock such as granite.Specifically,there is debate in the literature on the mechanisms(i.***.tensile and/or shear)by which these fractures initiate,propagate,and coalesce.We present experiments on Barre granite with pre-cut flaws where the material is loaded to high far-field stresses close to shear failure,and then the fluid pressure in the flaws is increased to move the Mohr’s circle to the left and observe the initiation and propagation of fractures using high-speed imaging and acoustic emissions(AEs).We find that the hydraulic fractures initiate as tensile microcracks at the flaw tips,and then propagate as a combination of tensile and shear microcracks.AE focal mechanisms also show elevated levels of tensional microfracturing near the flaw tips during pressurization and final failure.We then consider a numerical model of the experimental setup,where we find that fractures are indeed likely to initiate at flaw tips in tension even at relatively high far-field stresses of 40 MPa where shear failure is generally expected.

关键词： Acoustic emission(AE) Hydraulic fracturing Enhanced geothermal system(EGS) Microseismicity

增强乳腺X线摄影病灶周围影像组学分析在鉴别乳腺良恶性病变中的诊断性能

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

国际医学放射学杂志 2022年第2期 243-243页

作者： S.M.Wang Y.q.Sun R.M.li N.Mao q.li T.T.Jiang 林伟源

摘要目的对增强乳腺X线摄影（CEM）影像进行病灶周围区域影像组学分析，以鉴别乳腺良恶性病变。方法这项回顾性研究纳入2017年11月—2020年2月接受CEM的病

关键词：

Observation of inhomogeneity in congruent liTaO3 crystal

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Beijing Synchrotron Radiation Facility 2001年第2期 142-144,页

作者： X.B.Hu H.D.Jiang H.liu S.S.Jiang q.li J.Y.Wang C.q.Zhang B.Ten BeijingSynchrotronRadiationLaboratory InstituteofHighEnergyBeijing100039210093People’sRepublicofChina NationalLaboratoryofSolidStateMicrostructures NanjingUniversityNanjing210093People’sRepubli

The inhomogeneity in a congrunet liTaO3 crystal has been observed by transmission synchrotron topography.Many extraordinary regions exist in congruent liTaO3 crystal and they often show diffraction intensity different from that of ordinary regions in synchrotron topographs.Differential thermal analysis indiates that the Curie temperature of the extraordinary region is lower than that of ordinary region,and the extraordinary region is really a high defect density region.The diffraction contrast of the extraordinary region in synchrotron topographs is explained qualitatively by a calculation at the selected wavelength.2001 Published by Elsevier Science B.V.

关键词： liTaO3晶体钽酸锂晶体同步辐射形貌术结构分析 X射线分析