Aluminum powder metallurgy processing

In recent years, the aluminum powder industry has expanded into non-aerospace applications. However, the alumina and aluminum hydroxide in the surface oxide film on aluminum powder require high cost powder processing routes. A driving force for this research is to broaden the knowledge base about aluminum powder metallurgy to provide ideas for fabricating low cost aluminum powder components. The objective of this dissertation is to explore the hypothesis that there is a strong linkage between gas atomization processing conditions, as-atomized aluminum powder characteristics, and the consolidation methodology required to make components from aluminum powder;The hypothesis was tested with pure aluminum powders produced by commercial air atomization commercial inert gas atomization and gas atomization reaction synthesis (GARS). The commercial atomization methods are bench marks of current aluminum powder technology. The GARS process is a laboratory scale inert gas atomization facility. A benefit of using pure aluminum powders is an unambiguous interpretation of the results without considering the effects of alloy elements;A comparison of the GARS aluminum powders with the commercial aluminum powders showed the former to exhibit superior powder characteristics. The powders were compared in terms of size and shape, bulk chemistry, surface oxide chemistry and structure, and oxide film thickness. Minimum explosive concentration measurements assessed the dependence of explosibility hazard on surface area, oxide film thickness, and gas atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization oxidation of aluminum powder. An Al-Ti-Y GARS alloy exposed in ambient air at different temperatures revealed the effect of reactive alloy elements on post-atomization powder oxidation;The pure aluminum powders were consolidated by two different routes, a conventional consolidation process for fabricating aerospace components with aluminum powder and a proposed alternative. The consolidation procedures were compared by evaluating the consolidated microstructures and the corresponding mechanical properties. A low temperature solid state sintering experiment demonstrated that tap densified GARS aluminum powders can form sintering necks between contacting powder particles, unlike the total resistance to sintering of commercial air atomization aluminum powder

Epoxy-resin patterns speed shell-molding of aluminum parts

Half patterns cast from commercial epoxy resin containing aluminum powder are used for shell-molding of aluminum parts. The half patterns are cast in plastic molds of the original wooden pattern. Ten serviceable sand resin molds are made from each epoxy pattern

Synthesis and processing of composites by reactive metal penetration / Mohamad Zulkarnain Zakaria

This is a study about the effects of sintering temperature changes at various ratio percentage composition of the ceramic (alumina powder) and aluminum powder on the microstructure, hardness, strengthening and porosity behavior. The composition of sample earlier produced by compacting process using the pressure at 400 kpa into various percentage ratio are sample at 90% aluminum powder and 10% alumina powder, 80% aluminum powder and 20% alumina powder, 70% aluminum powder and 30% alumina powder, 60% aluminum powder and 40% alumina powder, 50% aluminum powder and 50% alumina powder. The total amount weights of each sample are noted for 10 gram respectively. The sample were sintered at various temperature such as 450°C, 550°C, 650°C, 750°C and 850°C. Experimental result on different compositions of metal-ceramic reaction couples indicates that reactive metal penetration can be general procedures to composite synthesis. Porosity test were carried out to determine the effect reactive metal penetration affords near-net-shape capability especially composition relation between aluminium and alumina. It was indicate that sample which were sintered at 450°C and 550°C were heavier than other temperature samples soaked in water for two hours. The maximum strength test that indicated in the sampe occur high sintered temperature at 850°C, sample of high load noted at high load occur in acomposition 90% aluminum powder and 10% alumina powder. The fracture toughness of reactively-formed metal ceramic composites increases with the increased in aluminium concentration and at high sintered temperature where this composition interact actively. Hardness value for the sample is also determined followed by microstructures observation. Generally, the strength and hardness value of the synthesized composite metal tend to increase with the rise ofthe sintering temperature

An Investigation of the Mechanical and Physical Characteristics of Cement Paste Incorporating Different Air Entraining Agents using X-ray Micro-Computed Tomography

Improving the thermal insulation properties of cement-based materials is the key to reducing energy loss and consumption in buildings. Lightweight cement-based composites can be used efficiently for this purpose, as a structural material with load bearing ability or as a non-structural one for thermal insulation. In this research, lightweight cement pastes containing fly ash and cement were prepared and tested. In these mixes, three different techniques for producing air voids inside the cement paste were used through the incorporation of aluminum powder (AL), air entraining agent (AA), and hollow microspheres (AS). Several experiments were carried out in order to examine the structural and physical characteristics of the cement composites, including dry density, compressive strength, porosity and absorption. A Hot Disk device was used to evaluate the thermal conductivity of different cement composites. In addition, X-ray micro-computed tomography (micro-CT) was adopted to investigate the microstructure of the air-entrained cement pastes and the spatial distribution of the voids inside pastes without destroying the specimens. The experimental results obtained showed that AS specimens with admixture of hollow microspheres can improve the compressive strength of cement composites compared to other air entraining admixtures at the same density level. It was also confirmed that the incorporation of aluminum powder creates large voids, which have a negative effect on specimens’ strength and absorption.EC/H2020/841592/EU/Ultra-Lightweight Concrete for 3D printing technologies/Ultra-LightCon-3

Characterization of aluminum powder ignition

Heating rate effect and particle size effect on ignition temperature of Al powder were studied to collect data for development of a possible Al powder ignition model. Aluminum ignition is associated with a highly accelerated burn rate and high combustion enthalpy. A new ignition model, which can adequately interpret these conditions, is needed to develop better propulsion fuels, explosives and incendiaries that use Al as an additive. This experimental program was focused on preparing framework for characterization of ignition kinetics of Al powder by determining the ignition temperature for different, systematically varied, heating rates and particle size. The experimental setup involved igniting Al powder coated on a small length of an electrically heated carbon filament. A three-color pyrometer and a high-speed camera were used in the project to determine the filament surface temperature at the instant of ignition. When using the pyrometer, a sharp rise in a photodiode signal from the powder coating was used to determine the ignition moment. The high-speed camera recorded both the temperature and the ignition moment. Two Al powders with different particle size (Alfa Aesar, Al 10 - 14 μm and Al 3 - 4.5 μm) were investigated. The powders were ignited at three different heating rates. A higher ignition temperature was observed for higher heating rate for both the powders. The powder with larger particles ignited at higher temperature for same heating rate

Shock-treated Lunar Soil Simulant: Preliminary Assessment as a Construction Material

In an effort to examine the feasibility of applying dynamic compaction techniques to fabricate construction materials from lunar regolith, preliminary explosive shock-loading experiments on lunar soil simulants were carried out. Analysis of our shock-treated samples suggests that binding additives, such as metallic aluminum powder, may provide the necessary characteristics to fabricate a strong and durable building material (lunar adobe) that takes advantage of a cheap base material available in abundance: lunar regolith

リュウタイ ウンドウ ノ カシカ ニヨル キショウ ジッケン ノ ショウカイ

Experimental apparatuses to visualize a fluid movement have been developed. The apparatuses are applied on the experimental simulation of climate system. Rayleigh-Benard convection was realized by heating the silicon oil in the metal plate. The fluid flow in the convection was visualized by using aluminum powder and thermography. A linear relation between convection cell size and depth of silicon oil is determined. Experiments on the prevailing westerlies wave motion was performed by using rotary water vessel, which was consisted of cylindrical laminar structures of ice water, water and hot water. Wavy motion of rotating water flow was observed by using aluminum powder. A relation of wave number of water flow and rotary speed is determined

Effect of Sintering Time on Properties of Carbon Nanotubes Reinforced Aluminum Composite

This report provides the reader about the experimental study done by the author regarding her Final Year Project entitled “Effect of Sintering Time on Properties of Carbon Nanotubes Reinforced Aluminum Composite”. Materials used for this project are Multi wall carbon nanotubes (MWCNTs) and aluminum powder. Research methodology of this project involves characterization of aluminum powder and MWCNTs powder, fabrication of green test samples by using powder metallurgy technique; mixing and compacting, followed with sintering of samples with different interval of time (60min, 90 min and 120 min) and finally, characterization of sintered samples based on dimension, density, hardness and correlated tensile strength with hardness

A fundamental approach to adhesion: Synthesis, surface analysis, thermodynamics and mechanics

The effects of composites as adherends was studied. Several other variables were studied by fractography: aluminum powder adhesive filler, fiber glass cloth scrim or adhesive carrier, new adhesives PPQ-413 and LARC-13, and strength-test temperature. When the new results were juxtaposed with previous work, it appeared that complex interactions between adhesive, adherend, bonding, and testing conditions govern the observed strength and fracture-surface features. The design parameters likely to have a significant effect upon strength-test results are listed