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971.
K. Natesan 《Oxidation of Metals》1988,30(1-2):53-83
Oxidation-sulfidation studies were conducted on sheet samples of nickel aluminide, containing 23.5 at. % Al, 0.5 at. % Hf, and 0.2 at. % B in an annealed condition and after preoxidation treatments. Continuous weight-change measurements were made by a thermogravimetric technique in exposure atmospheres of air, a low-
gas mixture, and low-
gas mixtures with several levels of sulfur. Detailed scanning electron microscopy (SEM), X-ray, and electron microprobe analyses of the corrosion product scale layers were performed. The air-exposed specimens developed predominantly nickel oxide; the specimen exposed to a low-
. 相似文献
972.
Spinel LiNi0.05Mn1.95O4 cathode material for lithium ion batteries was synthesized by solid-state reaction from coprecipitated Ni-Mn hydroxide precursors and characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and galvanostatic charge-discharge tests. It is found that LiNi0.05Mn1.95O4 powder has an ordered cubic spinel phase (space group Fd3m) and exhibits superior rate capability. After 450 cycles, the LiNi0.05Mn1.95O4/carbonaceous mesophase spheres(CMS) Li-ion batteries can retain 96.0% and 93.3% capacity at 5C and 10C charge/discharge rate, respectively, compared with 85.3% (5C) and 80.5% (10C) retention for LiMn204 batteries. However, the initial discharge capacity of LiNi0.05Mn1.95O4/CMS batteries at 1C charge/discharge rate (96.20 mA.h/g) is slightly lower than that of the LiMn2O4 batteries (100.98 mA.h/g) due to the increased average oxidation state of Mn inLiNi0.05Mn1.95O4. 相似文献
973.
974.
1 INTRODUCTIONMetallicglassisregardedasastatethatisofdis orderunlikecrystalalloyswith periodicatomstruc ture.Soitshowsexcellentcapabilitiesofsoftmag netism ,mechanics ,corrosionresistance ,etc .How ever ,mostofamorphousalloyswereproducedbyus ingrapidsolidificationmethodssuchassplatquench ing ,meltspinning ,andsoon ,withcharacteristiccoolingratesof 10 4 10 6 K/s .Becauseamorphousal loysarepreparedwithsilk ,powderandribbon ,itisgreatlylimitedinengineeringapplication .Recently ,severalbulk… 相似文献
975.
976.
Microstructure and mechanical properties of pure magnesium and AZ31 alloy with Ca/Si based refiner addition were investigated. The results indicate that addition of Ca/Si based refiners to pure magnesium and AZ31 alloy results in remarkable microstructure refinement. With proper amount of refiner addition, the grain size in as cast ingots can be one order of magnitude lower than that without refiner addition. Small amount of refiner addition to AZ31 alloy increases both ultimate strength and yield strength significantly,while the ductility of the alloy with refiner addition is similar to that without refiner addition. Addition of refiner improves the deformability of AZ31 alloy and extruded or hot rolled specimens (rods or sheets) with refiner addition exhibit higher surface quality and mechanical properties than those without refiner addition. 相似文献
977.
V. Samardzic E.S. Geskin G.A. Atanov A.N. Semko A. Kovaliov 《Journal of Materials Engineering and Performance》2007,16(3):375-389
The objective of this study was to investigate material deformation in the course of a high-speed (>1500 m/s) water impact
and to use the acquired knowledge for improvement of the forming technology. An experimental setup for projectile fabrication
was constructed and a series of experiments involving sub-millimeter and micron scale metal deformation was performed. The
geometry and topography of the generated samples were investigated using advanced surface examination techniques and the feasibility
of the liquid impact based micro-forming technology was demonstrated.
This article was presented at Materials Science & Technology 2006, Innovations in Metal Forming symposium held in Cincinnati,
OH, October 15-19, 2006. 相似文献
978.
在薄板铝合金变极性脉冲熔化极惰性气体保护焊中,采用全桥高压脉冲双向稳弧方式,研究了高压稳弧脉冲电压幅值、脉冲持续时间、脉冲触发时刻、基值电流对焊接电流过零稳定性的影响.在小基值电流过零时,稳弧脉冲电压比基值电流对焊接电流过零稳定性的影响大.焊接电流过零的稳定性与稳弧脉冲电压的上升率有关,稳弧脉冲电压上升率有一个临界区间,使焊接电流过零时不稳定,采用稳弧脉冲电压上升率判断焊接电流过零稳定性,能够为铝合金VP PMIG焊焊接电流过零再引燃提供有效、可靠的依据. 相似文献
979.
Design of Bulk metallic glasses with high glass forming ability and enhancement of plasticity in metallic glass matrix composites: A review 总被引:1,自引:0,他引:1
To overcome some of the limits of existing metallic alloys, a new alloy design concept has been introduced recently in order
to control the crystallinity, i.e. to utilize crystalline, quasicrystalline, and amorphous structures. In particular, bulk
metallic glasses (BMGs) receive great attention because of their unique properties due to their different atomic configuration.
Recently, significant progress in enhancing glass forming ability (GFA) has led to the fabrication of BMGs having potential
for application as structural and functional materials. Moreover, successful design of BMG matrix composite microstructure
suggests that the plasticity of BMGs can be controlled properly. In this review article, we introduce recent research results
on the design of BMGs with high GFA and on the enhancement of plasticity in metallic glass matrix composites. 相似文献
980.