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Characteristics and distribution of microstructures in high pressure die cast alloys with X-ray microtomography:A review
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作者 Hai-dong Zhao Xue-ling Wang +2 位作者 Qian Wan Wen-hui Bai Fei Liu 《China Foundry》 SCIE EI CAS CSCD 2024年第5期427-444,共18页
Al and Mg alloy high pressure die castings(HPDC)are increasingly used in automotive industries.The microstructures in the castings have decisive effect on the casting mechanical properties,in which the microstructure ... Al and Mg alloy high pressure die castings(HPDC)are increasingly used in automotive industries.The microstructures in the castings have decisive effect on the casting mechanical properties,in which the microstructure characteristics are fundamental for the investigation of the microstructure-property relation.During the past decade,the microstructure characteristics of HPDC Al and Mg alloys,especially micro-pores andα-Fe,have been investigated from two-dimensional(2D)to threedimensional with X-ray micro-computed tomography(μ-CT).This paper provides an overview of the current understanding regarding the 3D characteristics and formation mechanisms of microstructures in HPDC alloys,their spatial distributions,and the impact on mechanical properties.Additionally,it outlines future research directions for the formation and control of heterogeneous microstructures in HPDC alloys. 展开更多
关键词 high pressure die casting microstructure three-dimensional characteristics DISTRIBUTION al and Mg alloys
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Energy release characteristics of PTFE/Al/TiH_(2) reactive jet with different TiH_2 content
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作者 Chunlan Jiang Jingbo Zhang +2 位作者 Rong Hu Liang Mao Ming Li 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第9期168-176,共9页
Titanium hydride(TiH_(2)), a promising high-energy additive, is doped into PTFE/Al to optimize the energy output structure of the reactive jet and strive for better aftereffect damage ability to the target. Six types ... Titanium hydride(TiH_(2)), a promising high-energy additive, is doped into PTFE/Al to optimize the energy output structure of the reactive jet and strive for better aftereffect damage ability to the target. Six types of PTFE/Al/TiH_(2) reactive liners with different TiH_(2) content are prepared by the molding and sintering method. The energy release characteristics of PTFE/Al/TiH_(2) reactive jet are tested by the transient explosion energy test, and are characterized from pressure and temperature. The reaction delay time,pressure history, and temperature history of the energy release process are obtained, then the actual value of released energy and reaction efficiency of the reactive jet are calculated. The results show that the peak pressure and temperature of the PTFE/Al/TiH_(2) jet initially increase and then decrease with increasing TiH_(2) content. When the TiH_(2) content is 10%, the actual value of released energy and reaction efficiency increased by 24% and 6.4%, respectively, compared to the PTFE/Al jet. The reaction duration of the reactive material is significantly prolonged as the TiH_(2) content increased from 0% to 30%. Finally,combined with the energy release behaviors of PAT material and the dynamic deformation process of liner, the enhancement mechanism of TiH_(2) on energy release of the reactive jet is expounded. 展开更多
关键词 PTFE/al/TiH_(2) Reactive materials Shaped charge Impact energy release characteristics
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Research on the quasi-isentropic driving model of aluminized explosives in the detonation wave propagation direction
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作者 Hongfu Wang Yan Liu +5 位作者 Fan Bai Chao He Yingliang Xu Qiang Zhou Chuan Xiao Fenglei Huang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期596-618,共23页
Taking CL-20(Hexanitrohexaazaisowurtzitane)-based aluminized explosives with high gurney energy as the research object, this research experimentally investigates the work capability of different aluminized explosive f... Taking CL-20(Hexanitrohexaazaisowurtzitane)-based aluminized explosives with high gurney energy as the research object, this research experimentally investigates the work capability of different aluminized explosive formulations when driving metal flyer plates in the denotation wave propagation direction.The research results showed that the formulations with 43 μm aluminum(Al) powder particles(The particle sizes of Al powder were in the range of 2~43 μm) exhibited the optimal performance in driving flyer plates along the denotation wave propagation direction. Compared to the formulations with Al powder 13 μm, the formulations with Al powder 2 μm delivered better performance in accelerating metal flyer plates in the early stage, which, however, turned to be poor in the later stage. The CL-20-based explosives containing 25% Al far under-performed those containing 15% Al. Based on the proposed quasi-isentropic hypothesis, relevant isentropy theories, and the functional relationship between detonation parameters and entropy as well as Al reaction degree, the characteristic lines of aluminized explosives in accelerating flyer plates were theoretically studied, a quasi-isentropic theoretical model for the aluminized explosive driving the flyer plate was built and the calculation methods for the variations of flyer plate velocity, Al reaction degree, and detonation product parameters with time and axial positions were developed. The theoretical model built is verified by the experimental results of the CL-20-based aluminized explosive driving flyer plate. It was found that the model built could accurately calculate the variations of flyer plate velocity and Al reaction degree over time. In addition, how physical parameters including detonation product pressure and temperature varied with time and axial positions was identified. The action time of the positive pressure after the detonation of aluminized explosives was found prolonged and the downtrend of the temperature was slowed down and even reversed to a slight rise due to the aftereffect reaction between the Al powder and the detonation products. 展开更多
关键词 aluminized explosive Flyer plate experiment Quasi-isentropic theoretical model al reaction Driving characteristics
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Electrochemical characteristics of Al-Mg and Al-Mg-Si alloy in sea water 被引量:4
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作者 Seong-jong KIM Seung-jun LEE +1 位作者 Jae-yong JEONG Kyu-hwan KIM 《中国有色金属学会会刊:英文版》 CSCD 2012年第S3期881-886,共6页
Among Al alloys,particularly 5000 series Al Mg and 6000 series Al Mg Si often used as marine materials have excellent corrosion resistance,low melting point,and thereby showing recycling availability when compared to ... Among Al alloys,particularly 5000 series Al Mg and 6000 series Al Mg Si often used as marine materials have excellent corrosion resistance,low melting point,and thereby showing recycling availability when compared to other metals.Variety experiments were conducted to select the most suitable material for marine environments.All electrochemical experiments were conducted in natural seawater.The corrosion test was performed in many methods such as anodic/cathodic polarization and Tafel analysis using multi-channel potentio/galvanostat WMPG 1000.As results,anodic and cathodic polarization behaviors indicate the characteristics of passive state and concentration polarization by reduction reaction in dissolved oxygen,which shows excellent electrochemical behaviors.Tafel analysis results show no significant difference but 5052-O alloy of various alloy materials indicates the lowest corrosion current density.Therefore,5052-O Al alloy presents most anti-corrosion material in marine environment. 展开更多
关键词 al alLOY SHIP ELECTROCHEMICal characteristics CORROSION
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Atomic-layer-deposited Al_2O_3 and HfO_2 on InAlAs: A comparative study of interfacial and electrical characteristics 被引量:3
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作者 武利翻 张玉明 +1 位作者 吕红亮 张义门 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第10期459-463,共5页
Al2O3and HfO2thin films are separately deposited on n-type InAlAs epitaxial layers by using atomic layer deposition(ALD).The interfacial properties are revealed by angle-resolved x-ray photoelectron spectroscopy(AR-XP... Al2O3and HfO2thin films are separately deposited on n-type InAlAs epitaxial layers by using atomic layer deposition(ALD).The interfacial properties are revealed by angle-resolved x-ray photoelectron spectroscopy(AR-XPS).It is demonstrated that the Al2O3layer can reduce interfacial oxidation and trap charge formation.The gate leakage current densities are 1.37×106A/cm2and 3.22×106A/cm2at+1V for the Al2O3/InAlAs and HfO2/InAlAs MOS capacitors respectively.Compared with the HfO2/InAlAs metal-oxide-semiconductor(MOS) capacitor,the Al2O3/InAlAS MOS capacitor exhibits good electrical properties in reducing gate leakage current,narrowing down the hysteresis loop,shrinking stretch-out of the C-V characteristics,and significantly reducing the oxide trapped charge(Qot) value and the interface state density(Dit). 展开更多
关键词 high-k dielectric atomic layer deposition In al As characteristics
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Mg元素含量对Al-2Si-0.8Fe合金抗退火软化和导电性能的影响
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作者 黄程毅 李乘波 +5 位作者 李梦妮 杜军 任月路 刘磊磊 李玲 任瑾萱 《材料热处理学报》 CAS CSCD 北大核心 2024年第9期92-99,共8页
采用光学显微镜、扫描电镜、布氏硬度计、电子万能材料试验机和涡流导电仪等研究了Mg元素含量对Al-2Si-0.8Fe合金的微观组织、力学性能及导电性能的影响。结果表明:随着Mg元素含量的增加,铸态Al-2Si-0.8Fe合金的硬度和抗拉强度不断提高... 采用光学显微镜、扫描电镜、布氏硬度计、电子万能材料试验机和涡流导电仪等研究了Mg元素含量对Al-2Si-0.8Fe合金的微观组织、力学性能及导电性能的影响。结果表明:随着Mg元素含量的增加,铸态Al-2Si-0.8Fe合金的硬度和抗拉强度不断提高,而对其导电性能的影响相对较小;当Mg含量增至1.5%时,铸态合金的硬度和抗拉强度达到最大值,分别为77.1 HBW和190 MPa,较Al-2Si-0.8Fe合金的硬度(42.3 HBW)和抗拉强度(123.5 MPa)分别提升了82.3%和53.8%,而导电性能的下降幅度控制在2.9%以内。低温退火处理后,合金的导电率有所提升;当Mg含量超过1%时,退火态合金的硬度显著降低,出现退火软化现象;而在Mg含量低于1%时,退火态合金的抗拉强度和硬度并未明显下降,分别达到201.7 MPa和78 HBW,显示出良好的抗退火软化特性。添加少量的Mg后,合金的组织主要由初生α-Al、共晶Mg_(2)Si相以及长针状β-Al_(5)FeSi相构成,而随着Mg含量的增加,会发生β-Al_(5)FeSi→π-Al_8Mg_(3)FeSi_(6)反应,导致合金中Mg_(2)Si强化相数量减少,无法弥补铸态合金固溶强化对硬度的提升效果,从而产生退火软化现象。 展开更多
关键词 al-Si基合金 退火软化 凝固特征曲线 导电率
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Characteristics and Microstructure of a Hypereutectic Al-Si Alloy Powder by Ultrasonic Gas Atomization Process 被引量:3
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作者 Jun SHEN Zhuangde XIE Bide ZHOU and Qingchun LI School of Materials Science and Engineering, Harbin institute of Technology, Harbin 150O01. China Zhijun SU and Hongsheng LE Shanghai HitaChi Electrical Appliance Co. Ltd, Shanghai 201206, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第1期79-80,共2页
A hypereutectic Al-Si alloy powder was prepared by ultrasonic gas atomization process. The morphologies, microstructure and phase constituent of the alloy powder were studied. The results showed that powder of the all... A hypereutectic Al-Si alloy powder was prepared by ultrasonic gas atomization process. The morphologies, microstructure and phase constituent of the alloy powder were studied. The results showed that powder of the alloy was very fine and its microstructure was mainly consisted of Si crystals plus intermetallic compound A19FeSi3, which were.very fine and uniformly distributed. 展开更多
关键词 FESI characteristics and Microstructure of a Hypereutectic al-Si alloy Powder by Ultrasonic Gas Atomization Process al
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The electrical characteristics of a 4H-silicon carbide metal-insulator-semiconductor structure with Al_2O_3 as the gate dielectric 被引量:1
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作者 刘莉 杨银堂 马晓华 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第12期366-372,共7页
A 4H-silicon carbide metal-insulator-semiconductor structure with ultra-thin Al2O3 as the gate dielectric, deposited by atomic layer deposition on tile epitaxial layer of a 4H-SiC (0001) 80N-/N+ substrate, has been... A 4H-silicon carbide metal-insulator-semiconductor structure with ultra-thin Al2O3 as the gate dielectric, deposited by atomic layer deposition on tile epitaxial layer of a 4H-SiC (0001) 80N-/N+ substrate, has been fabricated. The experimental results indicate that the prepared ultra-thin Al2O3 gate dielectric exhibits good physical and electrical characteristics, including a high breakdown electrical field of 25 MV/cm, excellent interface properties (1 × 10^14 cm^-2) and low gate-leakage current (IG = 1 × 10^-3 A/cm 2@Eox = 8 MV/cm). Analysis of the current conduction mecha- nism on the deposited Al2O3 gate dielectric was also systematically performed. The confirmed conduction mechanisms consisted of Fowler-Nordheim (FN) tuaneling, the Frenkel-Poole mechanism, direct tunneling and Schottky emission, and the dominant current conduction mechanism depends on the applied electrical field. When the gate leakage current mechanism is dominated by FN tunneling, the barrier height of SiC/Al2O3 is 1.4 eV, which can meet the requirements of silicon carbide metal-insulator-semiconductor transistor devices. 展开更多
关键词 al2O3 4H-silicon carbide metal-insulator-semiconductor capacitor gate leakage current C-V characteristics
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Characteristics of isothermal adsorption and desorption of aluminum ion to/from humic acids 被引量:3
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作者 WANG Qiang WEI Shiqiang +1 位作者 HUANG Yuming ZHANG Jinzhong 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第5期579-584,共6页
The adsorption and desorption characteristics of Al^3+ to/from humic acids at different pH, ionic strength, and temperature were studied by the C-25 glucosan-gel chromatography method. The results showed that the max... The adsorption and desorption characteristics of Al^3+ to/from humic acids at different pH, ionic strength, and temperature were studied by the C-25 glucosan-gel chromatography method. The results showed that the maximum adsorption amount (Qmax) and adsorption constant (k) increased, whereas, the absolute value of standard thermodynamic molar free energy change (ΔGm^0) decreased with the increase of pH at constant ionic strength and temperature. With ionic strength increasing from 0 to 0.15 mol/L, Qmax, and k increased and the absolute value of ΔGm^0 decreased at constant pH and temperature. High temperature was unfavorable for the adsorption reaction, as indicated by the dramatic decrease of Qmax and the absolute value of ΔGm^0 with an increase in temperature. The standard thermodynamic molar free energy change (ΔGm^0) and the standard thermodynamic enthalpy change (ΔHm^0) of the adsorption reaction were both negative, suggesting that adsorption reaction was spontaneous and exothermic. The desorption rate of HA-Al^3+ complex accelerated with the decrease of pH, and a significant linear relationship could be obtained between pH and the desorption rates of Al^3+ from humic acids. These results demonstrated that the Al^3+ adsorption reaction was a "biphase" reaction, and adsorption occurred at both the interior and exterior adsorption sites of humic acids. 展开更多
关键词 adsorption and desorption characteristics al^3+ humic acid
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Tribological characteristics of new series of Al-Sn-Si alloys 被引量:4
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作者 袁鸽成 张新明 +1 位作者 娄燕雄 黎祚坚 《中国有色金属学会会刊:英文版》 CSCD 2003年第4期774-780,共7页
Tribological characteristics of new series of Al Sn Si alloys were investigated by means of pin disk types of wear testing machines, OM, SEM and EDAX. Rules about the influence of Sn, Si content and load on the fricti... Tribological characteristics of new series of Al Sn Si alloys were investigated by means of pin disk types of wear testing machines, OM, SEM and EDAX. Rules about the influence of Sn, Si content and load on the friction and wear characteristics of the alloys were ascertained. The friction factor and wear rate of the alloys decrease with increasing Sn content, the wear rate decreases but the friction factor varies hardly with increasing Si content. The friction factor of the alloys increases slightly and the wear rate increases observably with increasing load in the range of 1080 N. The wear mechanism of Al Sn Si alloys consists of ‘plough’ action and abrasive wear below 30 N; the adhesive and delamination mechanism are shown in the range of 3080 N. The tribological characteristics of Al Sn Si system are superior to those of Al Sn or Al Si systems due to their “peritectic type” island shape microstructure of Si surrounded with Sn. 展开更多
关键词 al-Sn-Si合金 铝合金 磨损 摩擦 SEM
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Mg对Al-22Si-10Ni合金组织和热学性能的影响
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作者 李鹏宇 张瑜璐 +3 位作者 李乙庚 隋明冉 南邵骏 杜军 《铸造》 CAS 2024年第2期174-179,共6页
Al-22Si-10Ni合金具有较高的导热性和较低的热膨胀特性,但硬度偏低,对其进行Mg合金化,研究Mg对该合金凝固组织和热学性能的影响。研究显示,Mg的加入主要影响合金的末期凝固进程,合金凝固末期反应由Al-Si-Al3Ni三元共晶反应向Al-Si-Mg2S... Al-22Si-10Ni合金具有较高的导热性和较低的热膨胀特性,但硬度偏低,对其进行Mg合金化,研究Mg对该合金凝固组织和热学性能的影响。研究显示,Mg的加入主要影响合金的末期凝固进程,合金凝固末期反应由Al-Si-Al3Ni三元共晶反应向Al-Si-Mg2Si三元共晶反应转变;热处理促进Mg_(2)Si析出,少量Mg加入后Al-22Si-10Ni合金的热导率小幅上升,继续添加Mg后,热导率出现下降;Mg对合金热膨胀系数影响较小,可显著提升合金的硬度。Al-22Si-10Ni-0.5Mg合金表现出优异的综合性能,其室温热导率130.3 W/(m·K),25~100℃范围内平均热膨胀系数为13×10^(-6)/K,硬度达到HV144,性能较为接近喷射沉积制备的高含量Al-50Si合金,具有成为电子封装用材料的潜能。 展开更多
关键词 al-22Si-10Ni合金 凝固特性 热导率 热膨胀系数 硬度
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Influence of heat treatment regimes on microstructures and fracture characteristics of 7055Al alloy containing Ag 被引量:1
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作者 李海 郑子樵 王芝秀 《中国有色金属学会会刊:英文版》 CSCD 2004年第3期505-509,共5页
Tensile properties, fracture characteristics and microstructures of 7055 aluminum-based alloy containing Ag after T6, T73 and RRA treatment were investigated. The results show that RRA treatment retains strength of 70... Tensile properties, fracture characteristics and microstructures of 7055 aluminum-based alloy containing Ag after T6, T73 and RRA treatment were investigated. The results show that RRA treatment retains strength of 7055-T6 with higher electrical conductivity close to that of 7055-T73 alloy, but its elongation decreases greatly. SEM fractographs reveal that intergranular cracking and shear-type transgranular cracking are both presented on the fracture appearance of 7055-T6 specimen. After T73 treatment, the fractographs mainly consist of dimple-type transgranular cracking with minor intergranular cracking. For 7055-RRA specimen, intergranular cracking dominates with minor dimples on the fracture surface. The type and size of precipitates, width of grain boundary and the ability of precipitates to impede dislocation motion vary with heat treatment regimes. Three frature models were built on the basis of microstructural analyses. 展开更多
关键词 铝合金 断裂 热处理制度 显微结构 穿晶断裂 晶间断裂
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Bonding Characteristics of the Intermetallic Compound Al_3Ti+Cr
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作者 Senying LIU Rongze HU Dongliang ZHAO and Chongyu WANG (Central Iron and Steel Research Institute, Beijing 100081, China)Ping LUO (National Research Center for Certified Material, Beijing 100013, China)Zhongjie PU (Florida International University, Miami 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1996年第3期180-184,共5页
Based on our structural model and a tight-binding Hamiltonian the eIectronic structure has been calculated by use of a recursion method (RM) for two models of the tetragonal DO22 and the cubic Ll2 crystal structures i... Based on our structural model and a tight-binding Hamiltonian the eIectronic structure has been calculated by use of a recursion method (RM) for two models of the tetragonal DO22 and the cubic Ll2 crystal structures in Al3Ti+Cr for contrast, from which bonding characteristics have been discussed. The results for the interaction energy (IE) show that Cr prefers to replacing Al site. Cr partly replacing Al can change the IE between the atoms and make the constriction of lattice constant c and the elongation of lattice constant a for the DO22 and thereby may induce the change of crystal structure from DO22 to L12. The results for bond order integral (BOI) and IE between the atoms also show that the strong (110) directional Cr-Ti bondings are existed.Thus, Al3Ti-base intermetallic compounds with addition of the Cr atom still remain brittle. 展开更多
关键词 Ti II al Bonding characteristics of the Intermetallic Compound al3Ti+Cr RES
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Influence of Post-Annealing on Electrical Characteristics of Thin-Film Transistors with Atomic-Layer-Deposited ZnO-Channel/Al_2O_3-Dielectric
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作者 王有航 马倩 +4 位作者 郑丽丽 刘文军 丁士进 卢红亮 张卫 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第5期131-134,共4页
High-performance thin-film transistors (TFTs) with a low thermal budget are highly desired for flexible electronic applications. In this work, the TFTs with atomic layer deposited ZnO-channel/Al2O3-dielectric are fa... High-performance thin-film transistors (TFTs) with a low thermal budget are highly desired for flexible electronic applications. In this work, the TFTs with atomic layer deposited ZnO-channel/Al2O3-dielectric are fabricated under the maximum process temperature of 200℃. First, we investigate the effect of post-annealing environment such as N2, H2-N2 (4%) and O2 on the device performance, revealing that o2 annealing can greatly enhance the device performance. Further, we compare the influences of annealing temperature and time on the device performance. It is found that long anneMing at 200℃is equivalent to and even outperforms short annealing at 300℃. Excellent electrical characteristics of the TFTs are demonstrated after 02 anneMing at 200℃ for 35 rain, including a low off-current of 2.3 × 10-13 A, a small sub-threshold swing of 245 m V/dec, a large on/off current ratio of 7.6×10s, and a high electron effective mobility of 22.1cm2/V.s. Under negative gate bias stress at -10 V, the above devices show better electrical stabilities than those post-annealed at 300℃. Thus the fabricated high-performance ZnO TFT with a low thermal budget is very promising for flexible electronic applications. 展开更多
关键词 ZNO in of Influence of Post-Annealing on Electrical characteristics of Thin-Film Transistors with Atomic-Layer-Deposited ZnO-Channel/al2O for TFT with al on
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Structural Characteristics of Rapidly Quenched Al-Si Alloys
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作者 Lin LIU(Institute of Solid State Physics, Academia Sinica, Hefei, 230031, China)Yuanda DONG(Dept. of Metallurgy and Materials, Shanghai University of Technology, Shanghai, 200072, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1994年第3期232-234,共3页
The structure of rapldly quenched Al-Si alloys (1 and 4 wt-%Si) was systematically studied by optical and transmission electron microscopy (TEM ) as welI as X-ray djffractjon (XRD). ExperimentaIresults show that rapid... The structure of rapldly quenched Al-Si alloys (1 and 4 wt-%Si) was systematically studied by optical and transmission electron microscopy (TEM ) as welI as X-ray djffractjon (XRD). ExperimentaIresults show that rapid solidification refines the grain size. extends the solid solubility of Si in Al and Introduces a high density ot defects which exist in the forms of vacancies, dislocations and dislocation loops. etc.. The decomposition process of the alloys was fol lowed by using differential scanning calorimeter (DSC) and the activation energy for precipitation of Si was obtained through Kissinger analysis. The precipitation behaviour of Supersaturated Si in both samples was further examined by TEM. It was found that Si mainly precipitated inside the grains in Al-1 wt-%Si alloy. while in Al-4 wt-%Si alloy. nearly all the Si precipitates distributed along the grain boundaries. This may be due to the structure difference between the alloys in as-quenched state 展开更多
关键词 al SI Structural characteristics of Rapidly Quenched al-Si alloys
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Size Effect of Electromagnetic Constitutive Characteristics of Ultrathin Al Films
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作者 Xuedong BAI+, Meng CHEN and Lishi WEN (Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015, China) R.F.Huang (Department of Physics & Materials Science, City University of Hong Kong, Kowloon, Hong Kong, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2000年第5期540-542,共3页
The ultrathin aluminum films with thickness in the range of 2~60 nm have been deposited by dc magnetron sputtering apparatus. Reflectance and transmittance of the obtained samples were measured with a WFZ-900-D4 UV/V... The ultrathin aluminum films with thickness in the range of 2~60 nm have been deposited by dc magnetron sputtering apparatus. Reflectance and transmittance of the obtained samples were measured with a WFZ-900-D4 UV/VIS spectrophotometer. The optical constant (n, k) and permittivity (ε', ε') were determined by applying Newton-Simpson recurrent substitution method. The results indicate that the electromagnetic constitutive characteristic of ultrathin aluminum films is a function of thickness and has obvious size effect. 展开更多
关键词 Size Effect of Electromagnetic Constitutive characteristics of Ultrathin al Films al
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Effect of Heat Treatment on the Corrosion Characteristics of Al-Li Alloys
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作者 K.H. W.Seah(Dept. of Mechanical Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 0511)(To whom correspondence should be addlessed)S. C. Sharma(Dept. of Mechanical Engineering, R.V.College of Engineering, Bangalore -560-059, 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1995年第5期385-387,共3页
Experiments were conducted to study the general room temperature corrosion characteristics of heat-treated and non-heat-treated Al-Li alloys with different Li compositions. Corrosion rate was measured using both the p... Experiments were conducted to study the general room temperature corrosion characteristics of heat-treated and non-heat-treated Al-Li alloys with different Li compositions. Corrosion rate was measured using both the polarisation method and the weight-loss method. It was observed that the samples with higher Li content had lower corrosion resistance than those with lower Li content. Moreover, for all the specimens tested, it was fOund that heat treatment at 180℃ for 2 h (for the purpose of precipitation hardening) severely reduced the corrosion resistance,whereas heat treatment at 180℃ for 6 h significantly increased the corrosion resistance. 展开更多
关键词 LI al Effect of Heat Treatment on the Corrosion characteristics of al-Li alloys
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A quasi-isentropic model of a cylinder driven by aluminized explosives based on characteristic line analysis
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作者 Hong-fu Wang Yan Liu +3 位作者 Fan Bai Jun-bo Yan Xu Li Feng-lei Huang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2022年第11期1979-1999,共21页
A quasi-isentropic study on the process of driving a cylinder with aluminized explosives was carried out to examine the influence of the aluminum(Al) reaction rate on cylinder expansion and the physical parameters of ... A quasi-isentropic study on the process of driving a cylinder with aluminized explosives was carried out to examine the influence of the aluminum(Al) reaction rate on cylinder expansion and the physical parameters of the detonation products. Based on the proposed quasi-isentropic hypothesis and relevant isentropic theories, the characteristic lines of aluminized explosives driving a cylinder were analyzed,and a quasi-isentropic model was established. This model includes the variation of the cylinder wall velocity and the physical parameters of the detonation products with the Al reaction degree. Using previously reported experimental results, the quasi-isentropic model was verified to be applicative and accurate. This model was used to calculate the physical parameters for cylinder experiments with aluminized cyclotrimethylenetrinitramine explosives with 15.0 % and 30.0 % Al content. The results show that this quasi-isentropic model can be used not only to calculate the cylinder expansion rule or Al reaction degree, but also to calculate the physical parameters of the detonation products in the process of cylinder expansion. For explosives with 15.0 % and 30.0 % Al, 24.3 % and 18.5 % of the Al was found to have reacted at 33.9 μs and 34.0 μs, respectively. The difference in Al content results in different reaction intensity, occurrence time, and duration of two forms of reaction(diffusion and kinetic) between the Al powder and the detonation products;the post-detonation burning reaction between the Al powder and the detonation products prolongs the positive pressure action time, resulting in a continuous rise in temperature after detonation. 展开更多
关键词 aluminized explosives Cylinder experiments Quasi-isentropic model characteristic line analysis Reaction degree of al powder Physical parameters of detonation products
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Characteristics of In_(0.52)Al_(0.48)As Grown on InP(100) Substrates by Molecular Beam Epitaxy: Growth Optimisation and Effects of Si Doping
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作者 S.F.Yoon(School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyng Avenue,Singapore 639798, Rep. of Singapore) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1997年第2期91-98,共8页
Growth of In0.52Al0.48As epilayers on InP (100) substrates by molecular beam epitaxy at a wide range of substrate tempreatures (470~550℃) and at different Si doping levels has been carried out. Low temperature photol... Growth of In0.52Al0.48As epilayers on InP (100) substrates by molecular beam epitaxy at a wide range of substrate tempreatures (470~550℃) and at different Si doping levels has been carried out. Low temperature photoluminescence (PL) and double-axis X-ray diffraction (XRD) analyses shaw a strong dependence of the PL and XRD linewidths, XRD intensity ratio (Lepi/Isub), and lattice-mismatch on the substrate temperature. The X-ray diffraction peaks of samples grown at law temperatures show a composition of smaller peaks, indicating the presence of disorder due to alloy clustering. Raman scattering measurements of the same samples show an additional higher energy mode at 273 cm-1 in addition to the InAs-like and AlAs-like longitudinal-optic (LO) phonon modes. Samples doped with Si show an inverted S-shaped dependence of the PL peak energy variation with the temperature which weakens at high doping levels due to a possible reduction in the donor binding energy. Supported be observations of a reduction in both the AlAs-like and InAs-like LO phonon frequencies and a broadening of the LO phonon line shape as the doping level is increased, the PL intensity also shows in increasing degrees at higher doping levels, a temperature dependence which is characteristic of disordered and amorphous materials. 展开更多
关键词 As Grown on InP characteristics of In Growth Optimisation and Effects of Si Doping Substrates by Molecular Beam Epitaxy INP al Si
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Characteristics of Faigue Crack Initiation in Ti-5Al-4Sn-2Zr-1Mo-0.7Nd-0.25Si Alloy
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作者 Jiafeng LEP Yuyin LIU +3 位作者 Shaoxuan GUAN Qingjiang WANG Zhongguang WANG Dong LI and Zhuangqi HU(State Key Lab. for Fatigue and Fracture of Materials, Institute of Metal Research, Chinese Academy of Sciences,Shenyan 110015, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1997年第3期238-240,共3页
The characteristics of fatigue crack initiation in Ti-5AI-4Sn-2Zr1Mo-O.7Nd-O.25Si alloy wereStudied. Two modes Of fatigue crack initiation were found. The Nd-rich phase particles displaybetter resistance to fatigue cr... The characteristics of fatigue crack initiation in Ti-5AI-4Sn-2Zr1Mo-O.7Nd-O.25Si alloy wereStudied. Two modes Of fatigue crack initiation were found. The Nd-rich phase particles displaybetter resistance to fatigue crack initiation than the matrix at lower stress. 展开更多
关键词 SN Mo characteristics of Faigue Crack Initiation in Ti-5al-4Sn-2Zr-1Mo-0.7Nd-0.25Si alloy ZR TI al Nd Si
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