PCM法泡沫铝的研究及应用现状

介绍了PCM法制备泡沫铝的国内外研究现状，讨论了一些因素对泡沫铝发泡行为及其孔结构的影响。并对PCM法大尺寸泡沫铝及复合结构的制备、应用做了介绍。最后对PCM法制备泡沫铝今后的发展方向和现存问题做了分析。     

PCM法泡沫铝孔结构控制工艺的研究现状

介绍了国内外PCM法制备泡沫铝的研究现状,并对利用PCM法制备泡沫铝过程中原料和工艺对其孔结构的影响进行了总结,分析了PCM法制备泡沫铝合金现存的问题及发展方向。     

PCM法泡沫铝合金的研究现状

介绍了泡沫铝的国内外研究现状和改善泡沫铝合金性能的途径,讨论了一些因素对PCM法制备泡沫铝发泡行为及其孔结构的影响。这些因素包括预制体制备方式、粉体颗粒粒度、TiH2的分解特性和冷却方式。并对PCM法制备泡沫铝合金今后的发展方向和现存问题做了分析。     

PCM法制备泡沫铝的研究现状及应用前景

论述了PCM法 (powder compacting melting) 制备泡沫铝的国内外研究现状,重点对该工艺参数对发泡过程的影响、发泡机理及泡沫铝复合结构进行了讨论,展望了PCM法制备泡沫铝的应用前景.     

泡沫铝材料研究现状分析

概述了泡沫铝材料国内外制备技术及应用研究现状,分析了泡沫铝材料制备工艺及性能优化研究过程中存在的问题,并对泡沫铝材料未来的研究及发展趋势做了简要分析。     

泡沫铝及其三明治结构累积叠轧制备

通过累积叠轧法制备泡沫铝.采用称重法研究泡沫铝孔隙结构,利用光学显微镜观察泡沫铝孔隙形貌.发现以TiH₂为发泡介质,当发泡温度660~680℃和发泡时间6~10 min时,利用累积叠轧法制备泡沫铝的孔隙结构特性最好.发泡温度和发泡时间的最佳值与发泡剂用量有关,TiH₂质量分数为1.5%,在670℃发泡8 min,泡沫铝的孔隙率可达到42%,孔径为0.43 mm.以制备的泡沫铝为夹芯,通过轧制复合制备了TC4钛合金/泡沫铝芯和1Cr18Ni9Ti不锈钢/泡沫铝芯三明治板.利用光学显微镜和能谱仪研究了三明治板的界面.面板与芯板间的化合反应形成了界面的反应层,界面实现了冶金结合.     

反重力渗流铸造法制备开孔泡沫铝材料

采用反重力渗流铸造法成功制备了开孔泡沫铝材料,分析了材料的准静态压缩性能及主要制备工艺参数与开孔泡沫铝空隙度之间的关系。研究结果表明：采用反重力渗流铸造法所制备的泡沫铝几乎没有宏观缺陷,孔洞分布均匀、孔壁结构完整;泡沫铝的空隙度对其压缩性能的影响很大,泡沫铝的屈服强度与平台应力均随空隙度的降低而升高;提高粒子预热温度、增大保压压力或延长保压时间,均有助于降低空隙度。     

一种新型泡沫铝及其表面改性

介绍了三种典型的泡沫铝制备方法,并比较了它们各自的优缺点.其中熔体吹气发泡法是一种新型的制备方法,此法生产的泡沫铝比重较轻,可以有效地节约资源,但其孔径大,降低了吸声系数.针对此项不足,采用表面复合铝纤维及高分子纳米涂层的方法,有效地加强了其吸声效果.     

泡沫铝材料的制备技术及其应用研究概述

简单介绍了泡沫铝材料的特性和发展进程,作为一种新型功能-结构金属复合材料,具有优异的综合性能和良好的应用前景。综述了泡沫铝材料的分类,分析了闭孔和开孔泡沫铝的制备方法和制备原理。并结合当前泡沫铝材料国内外最新研究进展以及在各个领域的应用情况,对未来研究发展的重点和趋势进行简要分析。     

冷压-溶解-真空烧结法制备泡沫铝的阻尼性能研究

采用冷压-溶解-真空烧结法制备泡沫铝，并用单自由度稳态正弦激励法对制备的不同孔隙度及不同孔径的泡沫铝的阻尼性能进行了研究，讨论了加入Y2O3对泡沫铝阻尼性能和力学性能的影响。结果表明：泡沫铝的阻尼性能随着孔隙度的增加而增加，随着孔径的增大而减小；加入适量的Y2O3可以改善泡沫铝的阻尼性能和力学性能，当Y2O3加入的质量分数为0．5％～0．8％时泡沫铝达到了最佳的阻尼性能和力学性能，但过量的Y2O3将导致阻尼性能和力学性能降低。     

Gas Release Behavior of Cu-TiH<Subscript>2</Subscript> Composite Powder and Its Application as a Blowing Agent to Fabricate Aluminum Foams with Low Porosity and Small Pore Size

Compared to traditional pore structure with high porosity (≥ 80 pct) and large pore size (≥ 3 mm), aluminum foams with low porosity (60 to 70 pct) and small pore size (≤ 2 mm) possess higher compressive property and formability. In order to achieve the goal of reducing pore size, Cu-TiH₂ composite powder prepared by ball milling preoxidized TiH₂ with Cu powder was used as a blowing agent. Its gas release behavior was characterized by thermogravimetric analysis and differential scanning calorimetry. The results show that the ball milling treatment can advance the gas release process and slow the gas release rate at the same time. All these changes are favorable to the reduction of porosity and pore size. Such Cu-TiH₂ composite powder provides an alternative way to fabricate aluminum foams with low porosity and small pore size.     

粉末烧结法制备开孔泡沫铝压缩性能的研究

采用粉末烧结工艺制备开孔泡沫铝并研究了其压缩性能，不同形态的尿素和氯化钠颗粒作为造孔剂使泡沫铝的孔隙度控制在70％。结果表明：粉末烧结法制备的泡沫铝呵以容易地控制孔隙度及孔径的大小，并且孔结构很好地保持了造孔剂的形状。不同的孔结构对泡沫铝的压缩性能具有显著影响，球形孔结构得到了最佳的压缩效果。     

Fabrication of Al-3.7?Pct Si-0.18?Pct Mg Foam Strengthened by AlN Particle Dispersion and its Compressive Properties

Al-3.7 pct Si-0.18 pct Mg foams strengthened by AlN particle dispersion were prepared by a melt foaming method, and the effect of foaming temperature on the foaming behavior was investigated. Al-3.7 pct Si-0.18 pct Mg alloy containing AlN particles was prepared by noncompressive infiltration of Al powder compacts with molten Al alloy in nitrogen atmosphere, and it was foamed at different foaming temperatures ranging from 1023 to 1173 K. The porosity of prepared foam decreases and the pore structure becomes homogeneous with increasing foaming temperature. When the foaming temperature is higher than 1123 K, homogeneous pores are formed in the prepared ingot without using oxide particles and metallic calcium granules, which are usually used for stabilizing a foaming process. This stabilization of the foaming at high temperatures is possibly caused by Al₃Ti intermetallic compounds formed at high temperature and AlN particles. Compression tests for the prepared foams revealed that the absorbed energy per unit mass of prepared Al-3.7 pct Si-0.18 pct Mg foam is higher than those of aluminum foams strengthened by alloying or dispersion of reinforcements. It is remarkable that the oscillation in stress, which usually appears in strengthened aluminum foams, does not appear in the plateau stress region of the present Al-3.7 pct Si-0.18 pct Mg foam. The homogeneity in cell walls and pore morphology due to the stabilization of pore formation and growth by AlN and Al₃Ti particles is a possible cause of this smooth plateau stress region.     

About the foamability of iron - carbon alloys

The foamability of iron-carbon alloys using the powder metallurgical process route was investigated. Pure iron and carbon powder with an addition of foaming agent were mixed and compacted. The foaming process started during heating the sample as soon as a temperature above the solidus temperature of the iron-carbon alloy was reached. Result of the process is an iron foam with a porosity of up to 60%. It was investigated, how the foaming behaviour is influenced by the parameters of alloy composition and compaction process. Different foaming agents (alkaline earth metal carbonates and metal nitrides) as well as different carbon additions and compacting processes were tested. It can be seen that sort and amount of foaming agent have an unexpected low influence on the expansion process whereas an increasing carbon content supports the expansion significantly. The use of different compacting processes has only little influence on the expansion itself, but highly effects both the pore distribution and homogeneity. The poor effect of the foaming agent cannot be satisfactorily explained. Investigations of a possibly premature gas emission or of a not gas-tight inclusion of the foaming agent do not show clear results. The support of the expansion by carbon additions can be attributed to the formation of CO-gas by the Vacher-Hamilton law during simultaneous formation of the liquid Fe-FeC-eutectic phase. The more inhomogeneous pore structure of iron foams caused by the use of hot-or hot isostatically pressed semi-finished products can be traced back to a higher internal gas pressure in the sample which results in a burst of the microstructure of the semi-finished product.     

Fabrication of foamable precursors by powder compression and induction heating process

In the powder compact melting technique, metallic foams are fabricated by heating a precursor, thus initiating cell growth and foam formation. Proper precursor fabrication is very important because the density distribution after foaming and the foamability are determined during the precursor-fabrication process. The fabrication of the precursor has to be performed very carefully because any residual porosity or other defects will lead to poor results in further processing. In order to evaluate the effect of the compaction parameters on the kinetics of the foaming process, a series of experiments were performed. In this study, 6061 aluminum foams having a closed-cell structure were fabricated by the powder compact method and an induction heating process. An induction coil was designed to obtain a uniform temperature distribution over the entire cross-sectional area of the precursor. To establish the foamable precursor fabrication conditions, the effects of process parameters such as titanium hydride content (0.1 to 1.5 wt pct) and the compression pressure of the foamable precursor (50 to 150 kN) on the pore morphology were investigated.     

Effect of Sn on the Dehydrogenation Process of TiH2 in Al Foams

The study of the dehydrogenation process of TiH₂ in aluminum foams produced by the powder metallurgy technique is essential to understanding its foaming behavior. Tin was added to the Al foam to modify the dehydrogenation process and stabilize the foam. A gradual decomposition and more retention of hydrogen gas can be achieved with Sn addition resulting in a gradual and larger expansion of the foam.     

On the possibility of producing sap foil by powder boiling

Conclusions It was shown in the investigation that SAP foil can be produced by direct rolling of the powder (ASP-1 powder). The processes consist of cold compacting rolling of the powder, sintering, intermediate rolling, and cold rolling.During the experiments on rolling of powder ASP-1, the dependence of the strip thickness on the fill ratio for SAP was determined. The data obtained are very close to the results published by G. A. Vinogradov for pure aluminum.