Papers by Keyword: Infiltration Casting

Abstract: Open-cell Al-Si foam samples were produced using infiltration casting technique. The metal infiltration process was performed in a specially designed and built setup consisting of a vertical chamber resistance furnace, a pressurization chamber connected to an Argon gas cylinder through a control manifold. To control the relative density of the produced foams, non-compacted and compacted preforms (5 MPa) were prepared from 2 or 4 mm NaCl particles. The compaction was performed using a hydraulic press in the same infiltration chamber. Argon pressure of 3 bars was applied to infiltrate the preforms with the aluminum alloy after melting at 750 °C. The produced aluminum foam specimens show no lack of filling, a high degree of preform replication, and good homogeneity of pore sizes. The preliminary physical and mechanical characterization tests, including relative density, plateau stress, densification strain, and elastic modulus of the foam, are comparable to the values reported in previous investigations, in which more complicated, time-consuming, higher energy, and costly techniques were used. Further investigations on wider ranges of particle sizes, compaction, and infiltration pressures are currently in progress.

Abstract: Ordered porous aluminum is a new kind of porous metals with great potential due to the ordered structure. However, traditional methods are difficult to fabricate the ordered structure. Considering the regularity of the structure, the indirect rapid prototyping method is proposed to prepare the ordered porous aluminum. In this study, the structure of ordered porous aluminum with cubic pores was designed. The infiltration casting process of the indirect rapid prototyping method was simulated by the software ProCAST. The infiltration method, infiltration temperature and preheated temperature were optimized by the numerical simulation investigation. The specimens of the ordered porous aluminum with different structure parameters were prepared successfully by utilizing the optimal process parameters. The actual temperature-time curve was recorded in the experiment of infiltration casting and compared with the curve obtained by simulation. It proved that the simulated results in this study were reliable. The structure characterizations and quasi-static compression tests were also carried out in this study. The compression curves of the ordered porous aluminum with cubic pores showed the typical feature of porous metals. The compressive properties and density of the ordered porous aluminum with cubic pores met the linear relationship.

Abstract: Metal matrix syntactic foams are consisting of metal matrix and hollow spheres in closely or randomly packed, which own multifunctional properties with lightweight, damping, heat insulation, energy absorption and have a vast application prospect. Steel matrix can extend the potential of syntactic foams as a materials class to several new fields of application. In this paper, the hollow alumina spheres were introduced into the steel matrix by infiltration casting, the minimum diameter of hollow spheres for infiltration is analyzed in theory, the steel matrix syntactic foams were successfully prepared, which contain two different sphere types with average diameter sizes 3.97mm and 4.72mm, and the average densities of syntactic foams were calculated to be 4.39 (spheres occupy 43.7% of the volume) and 3.74 g/cm³ (spheres occupy 52.1% of the volume), respectively. The microstructure characteristics of the steel matrix syntactic foam were analyzed by means of scanning electron microscopy and energy spectrum.

Abstract: Lead-foam is a type material holding high porosity and specific surface area and can be used as grid material of storage battery and anode material in zinc electrolysis. Based on the infiltration casting system designed according to Pascal's and pressure infiltration principle, lead-foam with porosity 58-61%, cell diameter 1.18-3.35mm was successfully manufactured via infiltration casting method where industrial sodium chloride (NaCl) particles were used as porogens. As preparation of preform is a key step in infiltration casting process, orthogonal tests were performed to study the some process parameters’ effects on the porosity of the preform and the orthogonal test results revealed that the rank from high to low of the parameters’ effects on the porosity of preform was porogen size, cold-compacting pressure, sintering time and sintering temperature.

Abstract: Foam aluminum is a novel porous functional material. There are many methods for preparation of foam aluminum, wherein an infiltration casting method in the liquid phase method can be selected for the preparation. In the forming of a pore structure of the foam aluminum, infiltration depth and pore uniformity are mainly influenced by technological parameters including particle size and preheating temperature of particles and a mold, molten aluminum casting temperature and vacuum degree.

Abstract: In this essay, the surface microstructure of infiltration casting of low-carbon ductile iron was studied in detail. The results show that the micro hardness from the cast infiltration layer to the matrix zone increased at first and then decreased, the maximum micro hardness was about HV1400, maternal surface hardness are greatly enhanced. Low carbon ductile iron can obtain good surface microstructure by using casting infiltration technology. The hardness of alloy layer on low carbon ductile iron matrix is greatly improved.

Abstract: The WC and high-Cr cast iron layer were obtained on the surface of ZG30 steel by infiltration casting process, so the surface alloying of ZG30 steel was realized. The microstructures and phase structures of penetrating layer were studied by SEM, TEM, XRD, the hardness of the test material was measured by the hardness tester, and the wear resistance was tested by wear test machine. The mechanism of alloyed layer forming was analyzed. The effects of WC contents on the wear resistance of alloyed layer were studied. The results show that the layer is dense, without pores, slag and other defects, the thickness of the alloyed layer is about 6-7mm, and the penetrating layer and matrix are metallurgical bonding. The maximum hardness of the alloyed layer surface is 820Hv. When the content of WC is 15%, the penetrating layer has the highest wear resistance which is 18.8 times as high as the matrix.

Abstract: The method of infiltration casting plus heat treatment process employing chromium wires and cast iron applied to in-situ synthesized (Fe,Cr)₇C₃ particulates bundle reinforced iron matrix composites. The phase analysis, microstructure, microhardness and wear-resistance of composite were observed and measured. The results show that it is possible to fabricate (Fe,Cr)₇C₃ particulates bundle reinforced iron matrix composite produced by this technology, and a special structure which called particulates bundle was fabricated. (Fe,Cr)₇C₃ particulates bundle were distributed in the forms of granular, lath-shaped and hexagon-shaped in the particulates bundle. The macrohardness of particulates bundle was 52 HRC, and the relative wear resistance of the composites is 2.3—23 times higher than that of the cast iron.