检索结果-南通市图书馆

Microstructure Analysis of Microwave Sintered Ferrous pM Alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology(Materials Science) 2009年第2期24卷 214-217页

作者：彭远东易健宏 State key laboratory for powder metallurgy Central South University

The prop.r.ies and microstructure of microwave and conventional sintered Fe-2Cu-0.6C powder metallurgy （pM） alloys were investigated. The exp.r.mental results show that microwave sintered alloy has the better prop.r.ies （sintered density 7.20 g/cm3, rockwell hardness 75 HrB, tensile strength 413.90 Mpa and elongation 6.0%）, comp.r.d with the conventional sintered counterp.r.. Detailed analyses by using optical microscopy and scanning electron microscopy （SEM） reveal that microwave sintered sample has finer microstructure with small, rounded and uniformly distributed p.r.s, and also demonstrate the presence of more flaky and granular pearlite in the mi- crowave sintered body, both of which account for the prop.r.y improvement. SEM images on the fracture morphology indicate that a mixed mode containing ductile and brittle fracture is presented in microwave sintered alloy, in contrast with the brittle fracture in conventional sintered counterp.r..

关键词： microwave sintering Fe-Cu-C pM alloys mechanical prop.r.y microstructure

Consolidation and Microstructures of Microwave Sintered W-25Cu Alloys with Fe Addition

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology(Materials Science) 2010年第3期25卷 437-443页

作者：罗述东易健宏 State key laboratory for powder metallurgy Central South University

W-25Cu alloys were microwave sintered in a 2.45 GHz multimode *** densification,microstructure and their dependence on sintering mode and Fe addition were investigated in *** to the volumetric heating intrinsic in microwave processing,a microstructure with larger W grain size in center regions was observed as against larger grain size in edge regions for conventional *** sintering demonstrates its intrinsic advantages such as rapid heating rate,densification enhancement and microstructural homogeneity;but it undesirably promotes W grain *** microwave sintering,the role of Fe addition on compact consolidation is not so substantial as under conventional *** Fe degrades the microstructural quality,generating worse uniformity and coarser W grains.

关键词： W-Cu alloy microwave sintering consolidation microstructure Fe addition

Warm Compaction process of p/M Steels by Orthogonal Testing Method

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology(Materials Science) 2008年第1期23卷 105-108页

作者：叶途明 yi jianhong pENG Yuandong XIA Qinglin WANG Hongzhong State key laboratory for powder metallurgy Central South University Changsha 410083 China No.1 Steelmaking plant Wuhan Iron and Steel Corporation Wuhan 430083 China

In order to achieve higher density of p/M steels using the die wall lubrication compacting method or powder lubricant in warm compaction process, the influence of different process p.r.meters on the green density of warm compacted samples was studied. According to the orthogonal test method, the authors systematically study the influence of the different compaction pressure, condition of lubrication and compaction temp.r.ture on the green density of the sample in the warm compaction process, and put forward the optimal process p.r.meter of warm compaction exp.r.ment. It is found that, a high compaction pressure （≥700 Mpa）, die wall lubrication combined with a small amount of internal lubricants, and fitting compaction temp.r.ture by different condition of lubrication, are the optimal p.r.meters in warm compaction process.

关键词： warm compaction orthogonal test method die wall lubrication p.r.icle rearrangement plastic deformation

Nb-and Ta-doped(Hf,Zr,Ti)C multicomponent carbides with enhanced oxidation resistance at 2500℃

在线全文

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2024年第3期13卷 332-344页

作者： Shiyan Chen Jinming Wang Zhaoke Chen Weilong Song yi Zeng Xingchao Li Tongqi Li Xiang Xiong State key laboratory of powder metallurgy Central South UniversityChangsha 410083China Aerospace research Institute of Materials&processing technology China Academy of Launch Vehicle TechnologyBeijing 100076China

Enhancing oxidation resistance of multicomponent carbides above 2000℃is critical for their thermal protection *** this p.r.ose,novel Nb-and Ta-doped(Hf,Zr,Ti)C multicomponent carbides were designed to improve their oxidation resistance at 2500℃.The results demonstrated that Nb and Ta doping reduced the oxidation rate constant by 16.67%and 25.17%,respectively,thereby significantly improving the oxidation resistance of(Hf,Zr,Ti)*** enhancement was attributed to the changes in oxycarbide composition and distribution within the oxide layer by adding Nb and *** to the different oxidation tendencies of the constituent elements,a distinctive structure was formed in which(Hf,Zr)O_(2)served as a skeleton,and various oxycarbides were disp.r.ed throughout the oxide *** doped Nb and Ta were retained within oxycarbides,retarding the diffusion of oxygen into the *** imp.r.antly,the addition of Nb and Ta reduced the size of oxycarbides,decreasing both size and quantity of the p.r.s in the oxide layer and facilitating the formation of a more effective oxygen barrier.

关键词： (Hf,Zr,Ti)C oxidation behaviour ultra-high-temp.r.ture oxidation Nb and Ta doping oxycarbides

Single-source-precursor synthesis and air-plasma ablation behavior of(Ti,Zr,Hf)C/SiC ceramic nanocomposites at 2200℃

维普期刊数据库评论

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 Advanced Ceramics 2024年第7期13卷 1043-1059页

作者： Li Lu Qingbo Wen Jinrun Hu Tianxing Jiang Xiangchao ren Yalei Wang yi Zeng Xiang Xiong State key laboratory of powder metallurgy Central South UniversityChangsha 410083China

Dense monolithic(Ti,Zr,Hf)C/SiC ceramic nanocomposites with four different molar ratios of metallic elements in the(Ti,Zr,Hf)C phase(i.e.,Ti:Zr:Hf=1:1:1,2:3:5,2:3:3,and 1:2:1)were prep.r.d upon p.r.lysis of novel(Ti,Zr,Hf)-containing single-source precursors(SSps),followed by sp.r. plasma sintering(SpS).A thorough characterization was conducted to elucidate the synthesis of the SSps,polymer-to-ceramic transformation,chemical/phase compositions,and microstructure of the SiTiZrHfC-based *** results revealed the feasibility of synthesizing nanocomposites with high(Ti,Zr,Hf)C contents using the SSp *** nanocomposites were characterized by a unique microstructure with in situ generated(Ti,Zr,Hf)C@C core-shell nanop.r.icles homogeneously mixed withβ-*** ablation behavior of the nanocomposites was evaluated on an air-plasma device for 60 ***,the nanocomposites exhibited excellent ablation resistance,and the lowest linear ablation rate reached−0.58μm/s at 2200°***,the ablation resistance can be dramatically improved by precisely tailoring the atomic ratios of metal elements within the(Ti,Zr,Hf)C phase via the molecular design of the *** formation of a multiple-oxide layer with both a high-meltingpoint phase((Ti,Zr,Hf)O_(2))and low-melting-point phases((Zr,Hf)TiO4)and glassy SiO_(2),as well as their structure,played a critical role in the enhanced ablation *** uniform distribution of the high-melting-point(Ti,Zr,Hf)O_(2)nano/microp.r.icles throughout the glassy SiO_(2)matrix significantly enhanced the viscosity and stability of the oxide layer by the pinning effect,offering sup.r.or protection against the ingress of oxygen atoms and excellent resistance to mechanical erosion.

关键词： ultrahigh-temp.r.ture ceramics(UHTCs) multicomponent carbide nanocomposites ablation behavior multiple oxides

An alternative ap.r.ach to improve the compatibility of pCE in cement paste blend with coal gangue powder

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Waste Disposal and Sustainable Energy 2024年第1期6卷 139-150页

作者： Zonglin Xie Yuxuan Li Dahui Sun yi Tian Jinyuan Hu Qiang Yuan Zheng Chen School of Civil Engineering Central South UniversityChangshaChina china railway NO.9 Group CO. LTDShenyangChina national Engineering research Center for High-Speed railway Construction technology ChangshaChina Guangxi key laboratory of Disaster prevention and Engineering Safety Guangxi UniversityNanningChina

Coal gangue(CG)is an environmental waste that faces an urgent demand for disposal in *** utilization of CG in construction materials has broad application prospects and gained increasing ***,the poor compatibility of polycarboxylate sup.r.lasticizer(pCE)with CG powder hinders its efficiency in a wide range of ***,this pap.r.attempts to improve the compatibility of pCE with CG powder in cement paste based on the regulation of aggregation and the adsorption behavior of *** light scattering(DLS)and fluorescence spectroscopy tests were carried out to understand the improved *** results indicated that the addition of CG powder increases the ionic strengths of the cement liquid phase,which makes pCE tend to aggregate at a lower concentration comp.r.d with no CG powder ***(CH_(3)COO)_(2)Cu is beneficial for enhancing the workability of cement paste by reducing pCE aggregation while maintaining the compressive strength of cement ***,(CH_(3)COO)_(2)Cu extra addition can be regarded as an effective and sustainable way to improve the workability of cement paste with CG powder.

关键词： Coal gangue powder polycarboxylate sup.r.lasticizer Compatibility Aggregation

Effect of forging on the microstructure and texture of a high Nb containing γ-TiAl alloy

维普期刊数据库评论

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 central south university 2024年第6期31卷 1763-1773页

作者： TAO Hui LI Hui-zhong WANG Li ZHOU rui CHE yi-xuan CHEN Yong-hui LIANG Xiao-peng School of Materials Science and Engineering Central South UniversityChangsha 410083China State key laboratory of powder metallurgy Central South UniversityChangsha 410083China key laboratory of Nonferrous Metal Materials Science and Engineering Central South UniversityChangsha 410083China Dep.r.ment of Materials Science and Engineering City University of Hong KongKowloon 999077Hong KongChina

The effect of forging on the microstructure and texture evolution of a high Nb containing Ti-45Al-7Nb-0.3W(at.%)alloy was investigated by X-ray diffractometer(XrD),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).The results show that the as-cast alloy is mainly composed of α_(2)/γ lamellar colonies with a mean size of 70μm,but the hot-forged pancake displays a near duplex microstructure(Dp).Kinking and bending of lamellar colonies,deformation twinning and dynamic recrystallization(DrX)occur during hot ***,dense dislocations in theβphase after forging suggest that the high-temp.r.ture β phase with a disordered structure is favorable for improving the hot-workability of the *** the common TiAl casting texture,the solidification process of the investigated as-cast alloy with high Nb content is completely via the β phase region,resulting in the formation of aγ fiber texture where theγ aligns p.r.llel to the heat-flow *** comp.r.son,the relatively strongand weaktexture components in the as-forged alloy are attributed to the deformation *** annealing,static recrystallization occurs at the twin boundary and intersections,which weakens the deformation texture.

关键词： high Nb containing γ-TiAl alloy forging microstructure texture β phase

Charge regulation by ferromagnetic metal/LiF spin-polarized interface for high-p.r.ormance Li metal anodes

在线全文

学校读者我要写书评

暂无评论

rare Metals 2024年第3期43卷 995-1005页

作者： Ming-Yang Feng Shuang Zhou yi-Fang Zhang Ya-ping Wang Chun-Yan Fu Jian-Wen Li Yuan-Lang Wan Zhi-Jia Zhang Yong Jiang An-Qiang pan State key laboratory of powder metallurgy School of Materials Science and EngineeringCentral South UniversityChangsha410083China State key laboratory of Sep.r.tion Membranes and Membrane processes Tianjin Key Laboratory of Advanced Fibers and Energy StorageSchool of Material Science and EngineeringTiangong UniversityTianjin300387China School of Materials Science and Engineering Hebei University of TechnologyTianjin300130China

The interfacial characteristics of the Li metal anode(LMA)play a crucial role in its overall *** various materials being applied to modify the interface,a comprehensive understanding of their specific mechanisms remains to be ***,we have prep.r.d carbon cloth(CC)frameworks with their surfaces modified using ferromagnetic metal/LiF heterogeneous films(T^(M)-LiF-CC)as the substrate for LMA,which exhibit sup.r.or electrochemical *** ferromagnetic Co as a representative example,our study demonstrates that the enhanced p.r.ormance of Co-LiF-CC,comp.r.d to bare CC,is attributed to the spinpolarized interface contributed by the Co/LiF *** and LiF play individual roles in redistributing electrons and Li^(+)to promote homogeneous Li *** nanop.r.icles play a crucial role in generating strong surface capacitance by storing electrons in spin-split bands,while LiF,with low surface diffusion barriers,ensures fast transp.r.ation of Li^(+).The Co-LiF-CC@Li electrodes deliver long lives of 7400 and 3600 h at 1 and 2 mA·cm^(-2)in symmetric cells,respectively;moreover,they enable full batteries with high and durable capacities,p.r.icularly when the N/p.r.tios are low(3.3 or even 1.7).

关键词： Lithium metal anode Interfacial charge Ferromagnetic metal Lithium fluoride Spin polarization

prep.r.tion of Fe-As alloys by mechanical alloying and vacuum hot-pressed sintering:microstructure evolution,mechanical prop.r.ies,and mechanisms

在线全文

学校读者我要写书评

暂无评论

rare Metals 2024年第8期43卷 3876-3892页

作者： Fei Chai Fei-ping Zhao Zhan Hu Shi-yi Wen Ben-Hammouda Samia Ze-Lin Fu Xin-Ting Lai Yan-Jie Liang Xiao-Bo Min Li-Yuan Chai School of metallurgy and Environment Central South UniversityChangsha 410083China Chinese national Engineering research Center for Control&Treatment of Heavy Metal pollution Institute of Environmental EngineeringCentral South UniversityChangsha 410083HunanChin State key laboratory of powder metallurgy Central South UniversityChangsha 410083China Dep.r.ment of Building Civiland Environmental EngineeringConcordia UniversityMontreal H3G 1M8Canada

Arsenic materials have attracted great attention due to their unique ***,research concerning iron-arsenic(Fe-As) alloys is very scarce due to the volatility of As at low temp.r.ture and the high melting point of ***,a new Fe-As alloy was obtained by mechanical alloying(MA) followed by vacuum hot-pressed sintering(VHpS).Moreover,a systematic study was carried out on the microstructural evolution,phase composition,leaching toxicity of As,and physical and mechanical prop.r.ies of Fe-As alloys with varying weight fractions of As(20%,25%,30%,35%,45%,55%,65%,and 75%).The results showed that pre-alloyed metallic powders(pAMps) have a fine grain size and specific sup.r.aturated solid solution after MA,which could effectively improve the mechanical prop.r.ies of Fe-As alloys by VHpS.A high density(> 7.350 g·cm^(-3)),low toxicity,and excellent mechanical prop.r.ies could be obtained for FeAs alloys sintered via VHpS by adding an ap.r.priate amount of As,which is more valuable than commercial Fe-As *** Fe-25% As alloy with low toxicity and a relatively high density(7.635 g·cm^(-3)) provides an ultra-high compressive strength(1989.19 Mpa),while the Fe-65% As alloy owns the maximum Vickers hardness(HVo.5 899.41).After leaching by the toxicity characteristic leaching procedure(TCLp),these alloys could still maintain good mechanical p.r.ormance,and the strengthening mechanisms of Fe-As alloys before and after leaching were *** in the grain size,micro structure,and phase distribution induced significant differences in the compressive strength and hardness.

关键词： Mechanical alloying Vacuum hot-pressed sintering High-pressure Arsenic-iron alloys Mechanical prop.r.ies