Preparation of big size open-cell aluminum foam board using infiltration casting

This paper presents an infiltration casting technique for manufacturing big size open-cell aluminum foam boards. The principle and key technologies of infiltration casting are also analyzed. Based on the previous practice of the small size aluminum foam production, the die for preparing big size aluminum foam boards is designed and manufactured. The experiments on aluminum boards of 300 mm × 300 mm × （20-75） mm, with the pore size ranging from 1.0 to 3.2 mm and average porosity of 60%, have been performed. The experimental results show that a reliable infiltration process depends critically on the pouring temperature of the molten AI-alloy, the preheated temperature of the mould and salt particles and vacuum. Current research explores the possibility of large-scale manufacturing and application of the aluminum foams.     

泡沫铝的低压渗流工艺研究

介绍了低压渗流法制备泡沫铝的装置,研究了影响液体金属渗流高度的工艺参数,总结了泡沫铝制备工艺过程中填料颗粒的性能要求及工艺参数的选取依据,并分析了泡沫铝常见的缺陷及产生的原因.     

采用反重力渗流法制备开孔泡沫铝(英文)

采用一套新颖的反重力渗流装置制备开孔泡沫铝。研究表明,采用反重力渗流法所制备的泡沫铝,表现出优良的力学性能且几乎没有渗流不足与渗流过度的缺陷;泡沫铝中的空隙度对其力学性能的影响很大,泡沫铝的屈服应力与平台应力均随孔隙度的降低而升高;升高预热温度与保压压强可有效降低泡沫铝中的空隙度。     

泡沫铝三明治结构粉末冶金法制备工艺及泡孔结构优化

粉末冶金法可实现泡沫铝三明治结构面板/芯层的冶金结合,并在制备近终型泡沫铝异型件上优势突出。基于国内研究现状,本文完善了粉末冶金法制备工艺,并优化了泡孔结构。研究发现,芯层采用AlMg4Si8铝合金成分组成,钢质面板经边缘焊接密封处理后,当芯层粉末松装密度为1.12 g/cm_³时,在1500 kN轧制压力、0.06 m/s轧制速度及55％轧制压下率下,对灌满芯层粉末的包覆面板进行450 °C热轧,获得了面板/芯层冶金结合、致密度高的发泡前驱体。另外,当发泡剂TiH₂被低熔点Sn包覆预处理后,在发泡初期分解出的H₂被液态Sn包裹,避免了在固态基体空隙间的扩散,减少了裂纹的产生,发泡前驱体在720 °C发泡300 s后可获得泡孔结构相对均匀、72.7%孔隙率的泡沫铝三明治结构。     

Tensile property of Al-Si closed-cell aluminum foam

1Introduction The unique properties of metallic foams make them useful in a number of potential application fields including damping,electromagnetic shielding,heat exchange,sound insulation,sound absorption,and energy absorption[1?4].The closed-cell alumi…     

Sound absorption property of open-pore aluminum foams

The sound absorption property of aluminum foam was studied by testing its sound absorption coefficients using standing wave tube method. The open-pore aluminum foams were prepared by infiltration process, with pore size of 0.5 mm to 3.2 mm and porosity of 54.2% to 77%. The frequency of indicted sound wave was ranging from 125 Hz to 10 kHz. The results show that the average values of sound absorption coefficients are all over 0.4 and the aluminum foam has better sound absorption property, its coefficients is influenced by frequency and pore structure, and reaches the maximum at about 1 kHz, with increasing porosity and decreasing cell diameter the sound absorption coefficient values increase.     

Ti40合金热压缩变形过程的开裂行为研究

用渗流铸造法制备了3种特殊孔结构(宽孔径范围孔结构、层状梯度孔结构、层状周期孔结构)的Al-Si12泡沫,对其吸声性能进行了研究.结果表明,相同厚度下,层数多的层状梯度孔径结构泡沫铝的吸声性能优于层数少的梯度孔径结构泡沫铝;层数多的层状周期孔结构泡沫铝的吸声性能比层数少的周期孔结构泡沫铝的吸声性能略有提高;具有4层周期孔结构的Al-Si12泡沫铝样品具有较好的吸声性能,其平均吸声系数为0.82,比常规单一孔径结构的泡沫铝的平均吸声系数提高了0.21,其原因与扩张室结构、流阻及微型谐振腔有关.     

ZG30MnSi中频炉熔炼工艺

介绍了中频感应电炉熔炼ZG30MnSi的工艺.通过对原材料质量的控制和化学成分的选择,及在终脱氧阶段,对脱氧铝及钢液残余铝量的控制,获得了高质量的钢液,有效地减少了铸件出现气孔、夹渣等缺陷,细化了铸件的内部组织,使铸件具有优良的综合力学性能,各项指标均超过国家标准.     

离心渗铸中铝熔液在多孔介质内的流动

依靠离心力使金属熔液渗入到短纤维预制件中，凝固后得到金属基复合材料。在不考虑传热影响的基础上，通过分析离心力场中铝熔液在Al2O3短纤维方形预制件中的渗流情况，研究了铝熔液质量、预制件孔隙率和模具转速对渗透压力的影响，推导出了临界渗透参数关系式，分析了各种条件下满足临界渗透的晟小转速、最小渗铸质量以及最小孔隙率及其相互之间的影响规律。结果表明，针对本研究所用模型，温度确定，铝熔液质量、模具转速以及预制件孔隙率决定着渗透能否发生；随着渗透前沿界面的不断推进，渗铸总压力也在逐渐增大，若起始时刻初始界面能满足临界渗透条件，渗铸过程将维持下去，直至渗透过程结束。     

先进孔形微型泡沫铝及其复合结构研究现状与展望

粉末压实熔化法(Powder Compact Melting,简称PCM法)是制备闭孔泡沫铝合金的方法之一。目前,通过对此方法进行改进,能够制备具有先进孔形(Advanced Pore Morphology,APM)的微型泡沫铝,所得产品内部为均匀的高孔隙率的多孔结构,并且利用所制得的微型泡沫铝,可以制备大尺寸的泡沫铝及其复合结构。综述了先进孔形微型泡沫铝及其复合结构的制备工艺,对其结构特征及力学性能进行了总结,分析了此工艺目前存在的问题,并对其发展前景进行了展望。     

铝合金爬坡TIG焊熔池失稳状态的视觉检测

对焊接过程中的熔池状态进行视觉检测是实现焊缝质量在线监测的重要手段. 针对中厚板铝合金爬坡钨极氦弧焊过程易出现的熔池失稳和成形缺陷问题,提出了一种基于熔池图像特征的钨极惰性气体保护焊(TIG)焊接状态监测方法. 基于构建的被动视觉传感系统,实现强弧光干扰条件下清晰熔池图像的获取. 提出了一种基于Otsu’s阈值分割和视觉显著性特征(VSF)的氦弧焊熔池图像处理算法,用于提取熔池图像的形态特征,并分析了所提取视觉特征与铝合金爬坡TIG焊过程稳定性的关系. 最后建立了支持向量机(SVM)模型实现熔池稳定性状态的在线识别. 结果表明,相对于熔池轮廓几何特征,熔池尾端熔融金属的形态特征能够更有效地反映出铝合金爬坡TIG焊过程中出现的熔池不稳定状态. 所建立的焊接状态分类模型在单一特征输入条件下,最高准确率达到95.94%. 所提出的实时检测方法为大型铝合金构件TIG焊缝成形缺陷的在线智能诊断与工艺优化提供了基础.     

泡沫铝制备工艺的改进及关键问题探讨

对熔体发泡法制备闭孔泡沫铝的工艺进行了改进,并研究了发泡过程中TiH2加入量和粒度对泡沫铝孔隙率的影响。改进后的泡沫铝生产工艺在工业化生产方面具有很好地推广价值,主要体现在连续性生产和能源综合利用方面。试验证实：随着TiH2加入量增加,泡沫铝孔隙率不断增加;随着TiH2粒度的加大,孔隙率先逐渐减小后增加。     

Aluminum alloy foam core sandwich panels fabricated from die casting aluminum alloy by friction stir welding route

An aluminum foam sandwiches (AFSs) consisting of ADC12 Al–Si–Cu die casting aluminum alloy foam and ADC6 Al–Mg die casting aluminum alloy face plates were fabricated. Using ADC12 die casting plates containing large amounts of gases as the starting material of the foam, ADC12 foam can be fabricated without using a blowing agent. Using FSW, both the uniform dispersion of the segregated gases and pore stabilization powder in the ADC12 die casting plates used to fabricate a foamable ADC12 precursor and the bonding of the ADC12 precursor to the ADC6 plates can be simultaneously achieved. Namely, the AFS precursor is expected to be obtained in fewer processing steps. From the visual observation of the fabricated AFSs, no deformation of the ADC6 plates occurred and the ADC6 plates on both sides of the aluminum foam remained parallel. From the X-ray CT observation of the fabricated AFSs, good pore structures without the infiltration of ADC12 foam into the ADC6 plates can be obtained at a holding temperature of 948 K and holding times of t = 10 and 11 min. In tensile tests on the fabricated AFSs, fracture occurred in the ADC12 foam parts but no fractures were observed at the bonding interface between the ADC12 foam and the ADC6 plates, that is, good bonding was obtained between the ADC12 foam and the ADC6 plates.     

泡沫铝的制备及其力学行为的研究

简要介绍泡沫金属的性能特点、制备方法及其应用.采用加压渗流法制备具有开孔结构的泡沫铝,并对此分别进行准静态和动态压缩实验,研究其静态和动态压缩应变力-应变响应特征、应变率效应和吸能特性.实践证明这种泡沫铝具有很明显的应变率效应.     

泡沫陶瓷过滤板过滤机制和过滤板选择

简要介绍了过滤板的结构与过滤机制以及选择过滤板的依据，对使用者评价和选择泡沫陶瓷过滤板有一定的参考价值。     

熔盐体系中电沉积制备TiB2镀层的研究现状

介绍了熔盐体系中电沉积制备TiB2镀层技术中熔盐的选择、电镀工艺和参数的选择，概述了不同熔盐体系中B离子、Ti离子在阴极沉积的电化学机珲以及TiB2的合成机理，论述了TiB2惰性阴极在铝电解工业中的研究现状，最后分析了熔盐体系中石墨电极上制备TiB2镀层的可行性。     

SiC泡沫陶瓷增强ZL205A铝合金复合材料的制备与性能研究

本实验通过挤压浸渗工艺成功制备了SiC泡沫陶瓷增强ZL205A铝合金复合材料,并研究了不同孔隙率的泡沫陶瓷增强相对复合材料性能的影响。通过微观结构分析,制备的复合材料两相间结合紧密,没有裂纹及其他缺陷产生。多孔陶瓷作为增强相可以有效地细化ZL205A合金的晶粒,多孔陶瓷孔隙率的降低,孔结构越小,合金晶粒越细小。对制备的复合材料进行力学性能测试,复合材料的硬度和抗弯强度最高能够达到127.6HV和415MPa。对制备的复合材料进行摩擦磨损测试,结果表明,连续陶瓷相的存在将铝基体严重的粘着磨损和剥落磨损转变为较轻的磨粒磨损,极大提升了复合材料的摩擦磨损性能,为其用于耐磨领域提供了理论依据。     

石膏型渗流法制备低密度开孔泡沫铝工艺研究

研究用可溶石膏型预制块制备低密度开孔泡沫铝的工艺。采用不同孔径的聚氨酯网状海绵为母体材料,用石膏粉、硫酸镁、铝矾土和水为配方制备石膏型预制块,并分析了硫酸镁和铝矾土的加入量对石膏型预制块可溶性和抗压强度的影响。通过加压渗流的方法制备出低密度的开孔泡沫铝,并对渗流参数的选择做出总结。结果表明：利用石膏型渗流法制得的开孔泡沫铝相对密度在0．1以下。     

ZG30MnSi中频炉熔炼工艺

介绍了中频感应电炉熔炼ZG30MnSi的工艺,通过对原材料质量的控制和化学成分的选择,在终脱氧阶段,对脱氧铝及钢液残余铝量的控制,获得了高质量的钢液,有效地减少了铸件出现气孔、夹渣等缺陷,细化了铸件的内部组织,使铸件具有优良的综合力学性能,各项指标均超过国家标准。     

Influence of the specific surface area of a porous nickel to the intermetallic compound generated by reaction of a porous nickel and aluminum

A new process is proposed to fabricate an intermetallic compound reinforced aluminum alloy matrix composite by using the reaction between porous nickel and molten aluminum alloy. The intermetallic compound reinforced aluminum alloy composite was manufactured with the low-pressure infiltration process method. The amounts of the intermetallic compounds under 3 different specific surface area of porous nickel and the porosity inside composites were investigated. Porous nickel reacted with molten aluminum alloy at 973 K, and the intermetallic compound of Al₃Ni was generated on the surface of the porous nickel. The generated intermetallic compound Al3Ni, was delaminated according to the difference of thermal expiation coefficient with nickel. And the intermetallic compounds moves in the direction of aluminum matrix. The area fraction of the intermetallic compounds increased with the increasing specific surface area of porous nickel. In addition, the defect inside the composite decreased by the increasing specific surface area of porous nickel.