共查询到19条相似文献,搜索用时 171 毫秒
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泡沫铝三明治结构的制备 总被引:9,自引:0,他引:9
采用粉末冶金发泡法制备了Ti/Al/Ti,Al/AlSi7/Al泡沫铝芯三明治结构,研究了泡沫铝制备工艺参数的影响,讨论了混粉、压力、温度等对发泡性能的影响,并对泡沫铝制备中的排液现象进行了探讨。 相似文献
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泡沫Al-6Si合金的制备工艺研究 总被引:3,自引:0,他引:3
采用熔体发泡法制备泡沫铝硅合金。研究发泡剂添加量、粘度、加热温度、搅拌速度等对孔隙率及孔结构的影响 ,并通过对发泡介质TiH2 的预处理 ,研究TiH2 形成表层氧化物对延缓其在熔体中的分解及发泡过程的作用。考察制备泡沫铝材料实验的再现性 ,从而确定最佳工艺参数。研究表明 ,以TiH2 为发泡介质 ,采用熔体发泡制备孔隙结构均匀 ,孔隙率为 60 %~ 80 %的泡沫铝硅合金的最佳工艺条件是 :加热温度为 610~ 63 0℃ ,TiH2 含量为 1.2 %~ 1.4%,金属钙加入量为 1.5 %,增粘搅拌时间为 4~ 5min ,搅拌速度约为 80 0r·min- 1 ;发泡介质分散搅拌时间为 3 0~ 40s,搅拌速度约为 2 0 0 0r·min- 1 。 相似文献
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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. 相似文献
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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. 相似文献
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H.-M. Helwig S. Hiller F. Garcia-Moreno J. Banhart 《Metallurgical and Materials Transactions B》2009,40(5):755-767
Aluminum AlSi8Mg4 alloy foams were produced by the powder compact foaming route using different parameters for the uniaxial
powder compaction step. Compaction time, pressure, and temperature were varied and were found to influence both the density
of the foamable precursor and the peak expansion reached during foaming. While peak expansion cannot be related to any single
pressing parameter alone in a simple way, a clear dependence of expansion on the precursor density was found. Densification
to a relative density between 97.5 and 99 pct yielded volume expansions of the foam up to 880 pct. Lower densities result
in weaker foaming, due to insufficient encapsulation of the blowing agent; in addition, we were surprised to find that higher
densification also has an adverse effect on peak expansion, most likely due to the elimination of nucleation centers or the
effect of entrapped compressed air. Precursor microstructures were analyzed to identify the mechanisms leading to the observed
density dependence of expansion. 相似文献
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Shyam Birla D. P. Mondal S. Das N. Prasanth A. K. Jha A. N. Ch. Venkat 《Transactions of the Indian Institute of Metals》2017,70(7):1827-1840
Closed Cell AA2014-cenosphere hybrid foams have been prepared through stir-casting technique using varying amount of CaH2 powder as foaming agent. The cenospheres in hybrid foams created micro-pores in the cell wall and in the plateau region. It reduced the requirement of CaH2 for foaming by 30–40% by attaining equivalent level of relative density. These foams have been characterized for of microarchitechtural characteristics and mechanical properties like strength, densification strain and energy absorption. The properties of hybrid foams have been compared with those of conventional AA2014-SiC foam and Al-cenosphere syntactic foam. The closed cell AA2014-cenosphere hybrid foam exhibited comparable plateau stress, densification strain and energy absorption characteristics to those of AA2014-SiC foams with same relative density. Empirical relations to correlate plateau stress, densification strain and energy absorption for entire range of porosities have been established. 相似文献
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Aluminium foams have become popular because of their properties such as high stiffness combined with very low density. The aluminium foams are being used in many applications like automobiles, railways, aerospace, ship building, household applications etc. The development of foam with consistent quality and study of foam structure–property relation is important for both scientific and industrial applications. Metallic foams are commonly produced using hydride and carbonates foaming agents. However carbonate foaming agents are safer to handle than hydrides and produce aluminum foam with a fine, homogenous cell structure, low cost and easily available. The number of pores per inch and relative density of the foam play an important role on their physical and mechanical properties. Hence it is very important to investigate effect of grain size of calcium carbonate foaming agent on pores per inch and relative density. The present work deals with the effect of grain size of the calcium carbonate forming agent on the physical properties of an eutectic Al–Si alloy closed cell foam. The foam was produced with different grain size of calcium carbonate (150, 106, 75, 53 µm) as a foaming agent. The pores per inch and density of the foam produced with different grain size of calcium carbonates as foaming agent are determined. Relative density is in the range of 0.21–0.34, pores per inch is in the range of 11–20 for the produced eutectic Al–Si alloy closed cell foam. It is observed that as grain size of calcium carbonate used for production of aluminium foam increases, the number of pores per inch decreases, relative density decreases and porosity increases. 相似文献
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Aluminum foam is a newly developed mobile and lightweight material with excellent energy absorption capacities. Applying aluminum foam as a sacrificial protection layer on the bearing faces of protected structures can mitigate blast effects on the resistance capacities of structures against impact or blast loading. The aluminum foam undergoes great plastic deformation under transient dynamic loads before becoming fully densified, making it excellent for mitigating blast effects on these structures. In this paper, we conducted quasi-static testing on two types of aluminum foam specimens and obtained the primary parameters for the mechanical properties of aluminum foam specimens. We then used these two types of aluminum foams to protect the reinforced concrete (RC) slabs, and we conducted a series of tests to investigate the performance of the aluminum foam–protected RC slabs against blast loads. We tested a total of five foam-protected slabs and one control RC slab in the blast test program. The test results, including displacement and acceleration histories, performance of specimens, and maximum and permanent deflections, were fully reported. We then discussed the efficiency of aluminum foam to mitigate blast loads on protected RC slabs. 相似文献
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Yeong Hwan Song Masakazu Tane Takuya Ide Yoshihiro Seimiya Bo Young Hur Hideo Nakajima 《Metallurgical and Materials Transactions A》2010,41(8):2104-2111
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. 相似文献
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C. S. Y. Jee Z. X. Guo J. R. G. Evans N. Özgüven 《Metallurgical and Materials Transactions B》2000,31(6):1345-1352
Metal foams with porosities greater than 90 pct were prepared by a novel powder metallurgy route using a polymeric vehicle.
Coarse titanium powder and fine carbonyl iron powder were tested. The powders were blended with each component of a two-part
polyol-isocyanate foaming system, and the resulting suspensions were mixed and allowed to expand. Although the resulting polymer-metal
foam was closed cell, particles were not retained in the windows. Upon pyrolysis to remove the resin, the windows opened and
the final sintered metal foam was reticulated. Such foams present very low sintered density and are correspondingly weak after
sintering but offer a fine reticulated structure with cell diameters in the region of 100 to 200 μm. They may have applications in the areas of catalysis, biomaterials, and composites. 相似文献
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T. Sieber U. Mühlich T. Liedke U. Ballaschk H. Berek C. G. Aneziris D. Ehinger S. Wolf L. Krüger 《国际钢铁研究》2011,82(9):1004-1016
The aim of the study is to clarify how far it is possible to describe the mechanical behavior of novel TRIP‐Steel/Mg‐PSZ composite open‐cell foam structures using beam networks generated from random tessellations. Conventional compression tests were performed with various foam samples. Furthermore, the deformation of open‐cell composite foams was observed as well by X‐ray computed tomography (XCT). Up to a compressive strain of 20% different stages of deformation could be observed. Respective bulk samples were manufactured by powder metallurgy and tested in order to determine the mechanical properties of the bulk material. Numerical simulations were employed based on the suitable modeling of foams exposed to mechanical loading. The predictions of the simulation are compared with the results of the deformation experiments. 相似文献