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1.
与传统的Ca增黏与TiH2发泡的泡沫铝熔体发泡制备方法不同,CaCO3在铝熔体中可同时用作增黏剂和发泡剂.现有TiH2泡沫铝制备技术在制备小孔径类球形孔泡沫铝及合金方面存在困难,以轻质Ca-CO3颗粒为基础研制的新型泡沫铝增黏发泡剂,其热分解特性平缓,通过理论与实验确定了CaCO3在制备过程中的使用比例,分析了孔结构并讨论了CaCO3在铝熔体中的分解热力学问题,稳定制备出小孔径(0.4-1.1mm)、中等孔隙率(40-79%)的类球形孔泡沫铝及其合金. 相似文献
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文章在叙述铝合金熔体处理剂应用现状与细化机理的基础上,分析了稀土添加剂、Al-Ti-B中间合金细化剂以及Re-Al-TiB中间合金对铝合金铸态组织的影响,接着对复合添加剂稀土铝钛碳中间合金作了应用研究。结果表明:稀土铝钛碳的细化效果显著、抗衰减能力优越,能合理改善材料的强韧性,是一种高效能新型铝合金处理剂。 相似文献
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采用二步法制备Al-Ti-C-Sr中间合金,预制AI-10Sr铝熔体温度850℃,用纯氩气精炼。采用自蔓延法预制Al-Ti-C铝液,氟钛酸钾和石墨粉加入熔体的温度为800℃-900℃,并在最终使熔体达到1200℃以上。合成Al-Ti-C-Sr中间合金是在Al-Ti-C熔体温度在800℃-900℃时加入AI-10Sr合金。再用制备好的Al-Ti-C-Sr中间合金对A356铝合金进行细化变质处理,具有细化和变质双重作用,效果明显。 相似文献
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颗粒增强铝合金基泡沫铝材料压缩性能的研究 总被引:1,自引:0,他引:1
利用熔体发泡法制备了颗粒增强铝合金基闭孔泡沫铝,进行了准静态压缩和动态压缩实验,并且与铝合金基泡沫铝的相关性能进行了比较.研究了不同相对密度的泡沫铝准静态压缩和动态压缩性能.添加颗粒能增强基体合金性能,改善泡沫压缩效果.结果表明,在动态压缩和准静态压缩中,随着密度增加,颗粒增强基泡沫铝的平台应力和弹性模量逐渐增大;动态情形下的能量吸收能力要高于准静态情形下的能量吸收能力.向熔体中添加适当比例的粉煤灰颗粒可产生显著的基体增强效果,有效提高泡沫铝的压缩性能. 相似文献
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研究了高钛晶粒细化中间合金的制造法以及它对铝合金的作用效果。试验结果表明,由于浇组时旋转离子压力作用,使铝钛合金细化剂中的Al3Ti颗粒明显减小,因而可使细化剂中允许的钛含量提高将近4倍,这样可大大减小细化剂在在被处理合金中的加入量。 相似文献
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系统研究了锶盐及其复合变质剂对铝硅合金的变质效果,以及几种处理方法对铝合金中杂质元素镁、锌的影响规律。所得主要结果是:锶盐可以使铝硅合金的硅相由针杆状变为长度尺寸在100μm以下的短杆状或弯曲的纤维状。锶盐变质剂存在着与锶变质相同的变质潜伏期现象,将锶盐与钠盐或磷盐复合变质能够消除这种现象。所研究的变质剂加入量小,提高合金的力学性能和使用性能;真空蒸发处理能够有效地降低铝合佥中的杂质锌量,向铝合金中吹入氟利昂与氮气的混合气体或加入六氯乙烷熔剂都能够有放地降低铝合金中的杂质镁量,根据铝合金的含镁量确定氟利昂的吹入量或六氮乙烷的加入量。 相似文献
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目的研究Al-B-N中间合金对1070铝合金力学性能和导电性的影响。方法向1070铝合金熔体中添加适量Al-B-N中间合金,借助其中的纳米AlN颗粒(AlN_P)强化铝基体,同时以AlB_2相去除铝中降低导电率的过渡族金属元素(如Zr,Cr,V等)。结果添加质量分数为2%的Al-B-N中间合金,1070铝合金强度由66MPa提高至85 MPa,导电率由60.14%IACS提升至62.12%IACS,较未添加之前分别提高了28.8%和3.2%,此时合金伸长率为35.8%。结论适量Al-B-N中间合金可以同时提高1070铝合金抗拉强度与导电率,实现协同强化。 相似文献
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Effects of Sr-modification and melt cleanliness on melt hydrogen absorption of 319 aluminium alloy 总被引:2,自引:0,他引:2
S. G. Shabestari S. M. Miresmaeili S. M. A. Boutorabi 《Journal of Materials Science》2003,38(9):1901-1907
The effect of Sr-modification on hydrogen content of commercial 319 aluminium alloy melts has been quantified, by using HYSCAN instrument at 685°C and 735°C. In addition, the effect of melt cleanliness on the hydrogen content of the melt has been studied. It has been found that the melt cleanliness has a significant effect on the reduction of hydrogen content of the melt. The hydrogen contents of Sr-modified cleaned melts were significantly lower (30-45%) than uncleaned melts (melts containing surface oxide layers) at both temperatures. Sr-modification had no marked effect on the hydrogen content of the melt at both temperatures, when measurements were carried out in a cleaned melt. Hydrogen content of strontium modified, uncleaned melts has been increased, particularly at 685°C. In order to study the melt hydrogen absorption susceptibility in Sr-modified alloys, the formation of different hydrogen containing compounds such as hydrides and hydroxide of modifiers and other alloying elements in Al-Si melts has been evaluated thermodynamically. It has been found that there is no hydrogen containing compound, which can form in aluminium melts, and if these compounds are introduced into the melt they will dissociated to release hydrogen. 相似文献
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《Materials Science & Technology》2013,29(7):925-930
AbstractTiCpowders have been spontaneously infiltrated by molten Al with the aid of a K-Al-Fflux. The fluxdissolves the oxide film on the surface of molten Al, facilitating wetting between 'clean' Al and TiC particle surfaces, enabling liquid to be rapidly drawn into the network of TiC particles by capillary forces. The resulting master alloy was readily incorporated and dispersedinto molten Al, Cu, and Mg, indicative that the additive was readily wetted by all three molten metals and that the particles in the additive were not joined together by strong bonds. The use of a flux to facilitate cleaning of TiC, dissolution of Al in the meltand the avoidance of direct contactbetween TiC and melt surface oxides, all contribute to improved wetting. The slightly poorer quality of the particle distribution and the lowest yield in the Cu based alloy, suggest that wetting is worst in this system. 相似文献
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研究了SiC颗粒增强铝基(SiC/Al)复合材料中Ca含量对SiC分散性的影响以及Ca含量对注气法制备的SiC/Al泡沫复合材料的压缩性能和结构的影响。首先,制备不同Ca含量的SiC/Al复合材料,用来制备SiC/Al泡沫复合材料的基本材料,并对不同Ca含量的SiC/Al泡沫复合材料进行压缩实验;然后,利用OM、SEM和XRD研究了SiC/Al复合材料及泡沫结构中Ca含量对SiC分散性的影响。结果表明:Ca的加入会明显影响SiC/Al复合材料中SiC的分布,且存在Ca含量临界值。当Ca含量小于1.5wt%时,SiC在基体中分布较均匀;当Ca含量达到或超过1.5wt%时,熔体中生成一种富含Al、Ca和Si的金属间化合物Ca2Al4Si3,且其体积分数和尺寸随Ca含量的提高而显著增大,SiC集聚在这些金属间化合物区域内及其边界上而影响SiC分布的均匀性。压缩实验表明,SiC/Al泡沫复合材料压缩应力-应变曲线的平台应力和抗压屈服强度随着Ca含量的增加有提高的趋势。相应的SiC/Al泡沫复合材料的胞壁厚度随着Ca含量的提高明显增加,这不仅与金属间化合物的形成提高了熔体黏度相关,更可能是与金属间化合物在熔体中尺寸随Ca含量提高而明显增大相关。 相似文献
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The foaming behavior of 5 wt.% Ti6Al4V (Ti64) particle (30–200 μm)-added Al powder compacts was investigated in order to assess
the particle-addition effects on the foaming behavior. Al compacts without particle addition were also prepared with the same
method and foamed. The expansions of Ti64 particle-added compacts were measured to be relatively low at small particle sizes
and increased with increasing particle size. At highest particle size range (160–200 μm), particle-added compacts showed expansion
behavior similar to that of Al compacts without particle addition, but with lower expansion values. Expansions studies on
30–45 μm size Ti64-added compacts with varying weight percentages showed that the expansion behavior of the compacts became
very similar to that of Al compact when the particle content was lower than 2 wt.%. However, Ti64 addition reduced the extent
of drainage. Ti64 particles and TiAl3 particles formed during foaming increased the apparent viscosity of the liquid foam and hence reduced the flow of liquid
metal from cell walls to plateau borders. The reduced foamability in the compacts with the smaller size Ti64 addition was
attributed to the relatively high viscosities, due to the higher cumulative surface area of the particles and higher rate
of TiAl3 formation between liquid Al and Ti64 particles. 相似文献
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The gas released from the titanium hydride decomposition is one of the key factors to influence the Al alloy melt foaming process.In this study,a set of decomposition kinetic equations of titanium hydride was acquired by separating its temperature programmed decomposition(TPD) spectrum,which was acquired by a special designed TPD apparatus with argon used as carrier gas and thermal conductivity cell as the detector.According to these equations,the decomposition and hydrogen release characteristics of titanium hydride at a fixed/elevated temperature are described quantitatively,which can be applied to forecast the Al alloy melt foaming process and furnish the theoretical basis for fabrication of three-dimensional complex shaped Al alloy foam. 相似文献
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Effects of melt temperature and mold preheating temperature on the fluidity of Ca containing AZ31 alloys 总被引:3,自引:0,他引:3
The effects of melt temperature and mold preheating temperature on the fluidity of Ca containing AZ31 alloys were evaluated
under various casting conditions. The flow lengths of AZ31-xCa alloy melt increased with increasing the melt temperature due
to lower viscosity and longer time to fill the mold cavity. The increment of the flow lengths of AZ31-xCa alloy melt with
increasing the mold preheating temperature was not large due to large diameter of circular cross section of mold cavity. The
fluidity of AZ31-xCa alloy melts was affected more forcefully by melt temperature than by mold preheating temperature under
casting conditions used in this study. Also, the flow lengths of AZ31-xCa alloy melt were affected by grain size of primary
solid particles solidified during filling mold cavity and surface oxide film due to addition of Ca. 相似文献
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Yan Ju Min Zuo Tongtong Liu Yongli Li Wenli Xia Juan Chen Degang Zhao Chengcheng Xu 《Advanced Engineering Materials》2023,25(17):2300325
Herein, the microstructure control and performance evolution of hypereutectic Al–20Mg2Si alloy with the addition of novel Al–3.3Ca–10Sb master alloy are investigated. It is found that AlCa11Sb9 and CaSb2 compounds are successfully synthesized through in situ melt reaction of masteralloy. With 0.45 wt% Al–3.3Ca–10Sb master alloy addition, primary Mg2Si particles in hypereutectic Al–20Mg2Si alloy are significantly refined from more than 150 μm to 10.7 μm, which are accompanied with the 3D morphologies changing from dendrites to octahedrons. After heat treatment, Brinell hardnesses of Al–20Mg2Si alloys are remarkably improved to 112 HB. Furthermore, it is also found that the cooling rate of Al–3.3Ca–10Sb master alloys has certain influence on the refinement effect of Al–Mg2Si alloys. The excellent complex modification of this master alloy on Al–20Mg2Si alloy can be attributed to the existence of CaSb2 particles as the heterogeneous nucleation sites of Mg2Si particles and the inhibiting growth effect of residual Ca atoms adsorbed on the surface of Mg2Si phase. 相似文献
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Fabrication characteristics are unstable in direct foaming method. Therefore, most of near net-shape metallic foams are produced, and investigated by powder metallurgy. Direct foaming method, however, has many benefits (i.e. reduce the unit cost of goods and fabrication process etc.) to fabrication of metallic foams. In this article, the fabrication characteristic of near net-shape metallic foams by direct foaming method was evaluated. Al and Plaster was used for base material and mould material respectively. Ca and TiH2 were added to molten Al as thickening and blowing agent for stable condition of bubbles. Thickening time was about 10 min with a stirring speed of 600 r/min. Foaming time was 30-120 s for evaluation of the optimum foaming condition. Amount of agent was selected by pre-experimental data. Porosity of near net-shape goods was measured by Archimedes method. On the other hand, it seems that increasing poring time and thickening agent make the poor porosity 相似文献