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玻璃铝基复合材料高温压缩流变行为研究 总被引:2,自引:0,他引:2
利用Cleeble-1500对玻璃铝基复合材料在温度为573—723K、应变速率为0.01s^-1~10s^-1的条件下进行高温压缩变形行为的研究。结果表明,应变速率和变形温度变化强烈影响复合材料的流变应力,流变应力随变形速率的提高而增大,随变形温度的升高而降低;玻璃铝基复合材料高温塑性变形时的流变行为可用Zener·Hollomon参数的双曲正弦函数来描述。 相似文献
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综述了铍中不同存在形式的铁铝杂质对铍材性能的影响,指出通过合适的时效热处理使铁、铝结合生成AlFeBe4物可改善铍材性能,探明了适宜的铁/铝比是生成AlFeBe4化合物的必要条件,并通过选取铍珠或控制粉末酸处理浓度,能制备出符合此铁/铝比要求的原料。 相似文献
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铍中铁铝杂质对铍材性能的影响 总被引:1,自引:0,他引:1
综述了铍中不同存在形式的铁、铝杂质对铍材性能的影响。指出,通过合适的时效热处理,使铍中的铁、铝结合生成AlFeBe4化合物,可改善铍材性能。分析并阐明了适宜的Fe/Al比为生成AlFeBe4化合物的必要条件,并了通过选取铍珠或控制粉末酸处理浓度,制备符剑此Fe/Al比要求的铍材原料的方法。 相似文献
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新型Al-Zn-Mg-Cu合金热变形流变应力特征 总被引:1,自引:4,他引:1
采用Gleeble-1500热模拟机进行热压缩变形实验,研究了一种新型Al-7.5Zn-1.6Mg-1.4Cu-0.12Zr合金在变形温度为380-460℃、应变速率为0.001~0.1 s-1条件下的流变应力特征,并利用TEM分析了合金在不同变形条件下的组织形貌特征.结果表明,应变速率和变形温度对合金流变应力的大小有显著影响,流变应力随变形温度的升高而降低,随应变速率的提高而增大;合金平均亚晶尺寸随温度补偿应变速率Zener-Hollomon参数的升高而减小.可用Zener-Hollomon咖参数描述该Al-Zn-Mg-Cu合金热变形时的流变应力行为. 相似文献
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在Oleeble-1500热模拟机上,对5083铝合金进行高温等温压缩热模拟,分析了流变应力与应变速率、变形温度之间的关系和高温变形的内在机理,同时血对合金元素对流变应力的影响进行了分析。结果表明:在应变速率为0.01s^-1、0.1s^-1、1s^-1(400℃、450℃)和0.01s^-1(350℃),其流变应力出现明显的峰值应力,表现出连续动态冉结品特征;在0.1s^-1、1s^-1(350℃),表现为稳态流变,为动态回复。采用双曲正弦形式的Arrhenius关系来描述5083铝合金高温变形时的流变应力,获得5083的材料常数A、α、n和Q分别为0.06918s^-1、0.01002MPa^-1、3.2819和149.67kJ/mol。在不同的应变率比值下计算应变率敏感(SRS)系数(m=dlnσ/dlnε),发现随着温度升高,应变增大,m值增大。 相似文献
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The effect of magnesium content on the aging behavior of Al-Zn-Mg-Cu alloy reinforced with alumina (A12O3) was studied by using the differential scanning calorimetry (DSC) technique and hardness measurement. The magnesium contents
were studied in the range from 1.23 to 2.97 wt pct. The addition of magnesium was found to increase the coherent Guinier-Preston
(GP) zones in com-posites. The apparent formation enthalpy of GP zones of composites (0.1V
f) was 0.932 cal/g for 1.23 wt pct magnesium content and 1.375 cal/g for 2.97 wt pct magnesium content. The precipitation time
to achieve the maximum hardness in the composites depends on the magnesium content. The time changed from 12 to 48 hours as
the magnesium content increased from 1.23 to 2.97 wt pct. Both Vickers microhardness and Rockwell hardness increased with
increasing magnesium content. The maximum hardness occurred in the composites that contained maximum amounts of GP zones and
η′ precipitates. However, the microhardness of the composites was always lower than that of monolithic alloys due to the alumina
fibers which caused the suppression of GP zones and η′ for-mation in the composites. 相似文献
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B. V. Radhakrishna Bhat Y. R. Mahajan Y. V. R. K. Prasad 《Metallurgical and Materials Transactions A》2000,31(3):629-639
The hot working characteristics of 2124 Al alloy matrix composites reinforced with 0, 5, 10, 15, and 20 vol pct of SiC particulate,
produced by the powder metallurgy route, were studied using processing maps. The maps based on the dynamic materials model
were generated from the flow stress data obtained from hot compression tests, carried out at strain rates ranging from 0.001
to 10 s−1 and temperatures ranging from 300°C to 525°C. All the compositions studied exhibited domains of dynamic recrystallization
(DRX) and superplasticity. Flow instabilities were found at higher strain rates and lower temperatures. The composite with
10 vol pct SiC showed a tendency for abnormal grain growth at lower strains, which manifested itself as a shift in the DRX
domain to lower strain rates and the disappearance of the superplasticity domain. 相似文献
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As an attempt to depart from conventional transient liquid phase sintering practice, solid state vacuum sintering was studied in loose powder and in hot quasi-isostatically forged samples composed of commercial inert gas atomized (CIGA) or high purity Al powder. The high purity Al powder was generated by a gas atomization reaction synthesis (GARS) technique that results in spherical powder with a far thinner surface oxide. After vacuum sintering at 525 °C for up to 100 h, SEM results showed that the GARS Al powder achieved significantly advanced sintering stages, compared to the CIGA Al powder. Tensile results from the forged samples also showed that although its ultimate tensile strength is lower, 95 vs. 147 MPa, the ductility of the GARS pure Al sample is higher than the CIGA Al sample. Forging also consolidated a model powder-based composite system composed of an Al matrix reinforced with quasi-crystalline Al–Cu–Fe powders, where the same powder synthesis methods were compared. Auger surface analysis detected evidence of increased matrix/reinforcement interfacial bonding in the composite sample made from GARS powder by alloy interdiffusion layer measurements, consistent with earlier tensile property measurements. The overall results indicated the significant potential of using Al powders produced with a thin, high purity surface oxide for simplifying current Al powder consolidation processing methods. 相似文献
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The interfacial reaction characteristics of SCS-6, Sigma, and B4C/B fibers with nickel aluminide (Ni3Al) matrix have been investigated between 780°C to 980°C for times ranging from 1 to 100 hours. The microstructure and elemental
compositions across the reaction zone have been analyzed quantitatively using microscopy and electron probe microanalyses,
respectively. The results show that Ni3Al reacts extensively with SCS-6, Sigma, and B4C/B fibers to form complex reaction products, and Ni is the dominant diffusing species controlling the extent of reaction.
In the SiC/Ni3Al composite, the C-rich layer on the SiC surface can slow down but cannot stop the inward diffusion of Ni into SiC fiber.
When the C-rich layer is depleted, a rapid increase in reaction zone thickness occurs. Diffusion barrier coating on the fibers
is required to minimize the interfacial reactions. 相似文献
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N. Chawla U. Habel Y. -L. Shen C. Andres J. W. Jones J. E. Allison 《Metallurgical and Materials Transactions A》2000,31(2):531-540
The effect of matrix microstructure on the stress-controlled fatigue behavior of a 2080 Al alloy reinforced with 30 pct SiC
particles was investigated. A thermomechanical heat treatment (T8) produced a fine and homogeneous distribution of S′ precipitates,
while a thermal heat treatment (T6) resulted in coarser and inhomogeneously distributed S′ precipitates. The cyclic and monotonic
strength, as well as the cyclic stress-strain response, were found to be significantly affected by the microstructure of the
matrix. Because of the finer and more-closely spaced precipitates, the composite given the T8 treatment exhibited higher yield
strengths than the T6 materials. Despite its lower yield strength, the T6 matrix composite exhibited higher fatigue resistance
than the T8 matrix composite. The cyclic deformation behavior of the composites is compared to monotonic deformation behavior
and is explained in terms of microstructural instabilities that cause cyclic hardening or softening. The effect of precipitate
spacing and size has a significant effect on fatigue behavior and is discussed. The interactive role of matrix strength and
SiC reinforcement on stress within “rogue” inclusions was quantified using a finite-element analysis (FEA) unit-cell model. 相似文献
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Damping behavior of 6061Al/Gr metal matrix composites 总被引:9,自引:0,他引:9
R. J. Perez J. Zhang M. N. Gungor E. J. Lavernia 《Metallurgical and Materials Transactions A》1993,24(3):701-712
The damping behavior of graphite particulate-reinforced 6061A1 alloy metal matrix composites (MMCs) processed by spray atomization
and codeposition is studied. Four spray deposition experiments are made, yielding materials with graphite volume fractions
of 0, 0.05, 0.07, and 0.10. A dynamic mechanical thermal analyzer is used to measure the damping capacity and elastic modulus
at 0.1, 1, and 10 Hz over the temperature range of 30 °C to 250 °C. The damping capacity of the materials is shown to increase
with increasing volume fraction of graphite. Hot extrusion of the spray-deposited MMCs is shown to further increase the damping
capacity. The elastic moduli of the spray-deposited MMCs are reduced with the addition of graphite but are improved by hot
extrusion. At low temperatures (below 150 °C), the high damping capacity of the MMCs is attributed primarily to thermal expansion
mismatch-induced dislocations and the high intrinsic damping of graphite. At high temperatures (above approximately 200 °C),
the damping capacity is attributed to Al/graphite interface viscosity, preferred orientation of the graphite, and the presence
of dislocations. 相似文献