scholarly journals Sustainable Production of Powder Metallurgy Aluminum Foams Sintered by Concentrated Solar Energy

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1544
Author(s):  
Antonio Cañadilla ◽  
Ana Romero ◽  
Gloria P. Rodríguez
Keyword(s):  
Compressive Strength ◽  
Powder Metallurgy ◽  
Solar Energy ◽  
Energy Absorption ◽  
Impact Energy ◽  
Low Cost ◽  
Powder Metallurgy Method ◽  
Aluminum Foams ◽  
Space Holder ◽  
Concentrated Solar Energy

Porous aluminum foams were successfully fabricated following the space-holder powder metallurgy method with a solar sintering stage. Al foams with porosities of 50, 60, and 70 vol.% were sintered in a low-cost Fresnel lens. Green parts were prepared using aluminum powder as the main metallic material and saccharose as a soluble space-holder. The dissolution stage was designed for each foam and required longer periods of time, between 8 and 32 h, as the design porosity increased. Brown parts were fully sintered by concentrated solar energy at a lower temperature (500 °C) and for shorter times (12–20 min) than those required by conventional sintering techniques (640 °C, ~9 h). The evaluation of density and the characterization of pore size and distribution in the sintered foams was carried out. All obtained foams were stable and presented a homogeneously distributed porosity, very close to the design porosity, with differences lower than 2.1 vol.%, and with approximately half being characterized as open porosity. Moreover, the solar sintered foams presented a high quality, and similar or even greater mechanical properties (such as compressive strength and impact energy absorption) than those achieved by conventional techniques. Foams with 50 vol.% of porosity exhibited the best mechanical behavior, in terms of impact-energy absorption (24.42 MJ/m3) and compressive strength (27.4 MPa).

Transient Heat Delivery and Storage Process in a Thermocline Heat Storage System

2009 ◽  
Author(s):  
Jon T. Van Lew ◽  
Peiwen Li ◽  
Cho Lik Chan ◽  
Wafaa Karaki ◽  
Jake Stephens
Keyword(s):  
Solar Energy ◽  
Power Systems ◽  
Heat Storage ◽  
Low Cost ◽  
Storage System ◽  
Filler Material ◽  
Working Fluid ◽  
Efficient Computation ◽  
Concentrated Solar Energy ◽  
Feasible Option

Parabolic trough power systems utilizing concentrated solar energy have proven their worth as a means for generating electricity. However, one major aspect preventing the technologies widespread acceptance is the deliverability of energy beyond a narrow window during peak hours of the sun. Thermal storage is a viable option to enhance the dispatchability of the solar energy and an economically feasible option is a thermocline storage system with a low-cost filler material. Utilization of thermocline storage facilities have been studied in the past and this paper hopes to expand upon that knowledge. The current study aimed to effectively model the heat transfer of a working fluid interacting with filler material. An effective numerical method and efficient computation schemes were developed and verified. A thermocline storage system was modeled under specific conditions and results of great significance to heat storage design and operation were obtained.

Design and Construction of a Solar-Powered Fluidyne Test Bed

2011 ◽  
Author(s):  
Jackson W. Mason ◽  
James W. Stevens
Keyword(s):  
Solar Energy ◽  
Low Cost ◽  
Fresnel Lens ◽  
Primary Energy ◽  
Distinct Advantage ◽  
Test Bed ◽  
Capital Costs ◽  
Concentrated Solar Energy ◽  
Low Efficiency ◽  
Solar Powered

Liquid piston Stirling engines (sometimes termed “fluidynes”) have been studied extensively and applied in a variety of energy conversion applications. They are attractive for low capital costs and simplicity of construction. In addition, their operation as external combustion engines allows for flexibility in primary energy sources which is a distinct advantage when a low-cost or free source of heat can be paired with their minimal construction costs. Disadvantages of these devices include relatively low efficiency and low power density. A solar-powered fluidyne test bed was constructed and operated at the University of Colorado at Colorado Springs. This test bed was composed of a fluidyne engine which was constructed from copper pipe and plastic tubing along with temperature and pressure instrumentation. The system was designed to be powered by a Fresnel lens concentrating solar energy. The concentrated solar energy from the Fresnel lens provided ample power to operate the test bed, and tests were run in a wide variety of conditions. Indicated work of this unloaded engine was shown to agree well with a simple theoretical model of a Stirling cycle.

Dissolution Method of Aluminum Foams Containing Mg Using Carbamide Space Holder

2017 ◽  
Vol 888 ◽  
pp. 373-376
Author(s):  
Amirah Ahmad Hamdi ◽  
Nurul Akmal Mohd Sharif ◽  
Anasyida Abu Seman
Keyword(s):  
Energy Absorption ◽  
Aluminum Foam ◽  
Aluminium Foam ◽  
Aluminum Foams ◽  
Dissolution Method ◽  
Space Holder

This study investigated the properties of aluminium foam containing Mg with various amount of space holder. Aluminum foam was fabricated using dissolution method with various amount of carbamide (20, 40 and 60 wt. %). Aluminum foam with 60 wt. % carbamide has the lowest density (0.68 g/cm3) and exhibited the highest porosity (74.97%). However, the results indicates that aluminum foam with 40 wt. % of carbamide have good compressive and energy absorption with acceptable density and porosity value.

Processing and Development of a New High Strength Metal Foam

2004 ◽  
Vol 851 ◽  
Author(s):  
A. Rabiei ◽  
Adrian T. O'Neill ◽  
Brian P. Neville
Keyword(s):  
Compressive Strength ◽  
Composite Materials ◽  
Powder Metallurgy ◽  
Hollow Sphere ◽  
Metal Foam ◽  
Cell Structure ◽  
Powder Metallurgy Method ◽  
Casting Technique ◽  
Closed Cell ◽  
Foam Composite

ABSTRACTThe research sited in this paper involves the development of new closed cell metal foam composite materials using powder metallurgy (PM) and gravity casting techniques. The foam is comprised of steel hollow spheres packed into a random dense arrangement, with the interstitial space between spheres occupied with a solid metal matrix. Using a casting technique, an aluminum alloy infiltrates the interstitial spaces between steel spheres. In a powder metallurgy method, steel spheres and iron powder are sintered to form a solid, closed cell structure. The measured densities of the Al-Fe composite foam and iron foam are 2.4 g/cm3 and 3.2 g/cm3, with relative densities of 42% and 41% respectively.The hollow sphere metal foam composite materials developed in this study displayed superior compressive strength as compared to hollow sphere foams currently being produced. The compressive strength of the cast Al-Fe foam averaged 67 MPa over a region of 10 to 50% strain, while the steel PM foam averaged 45 MPa over the same strain region. Densification began at approximately 50% for the cast foam and 55% for the PM foam.

The structure and properties of porous copper produced by powder metallurgy using NaCl as space holder agent

2021 ◽  
Vol 94 ◽  
pp. 2-7
Author(s):  
Trung Tran Bao ◽  
◽  
Phuong Doan Dinh ◽  
Toan Nguyen Van ◽  
Hoan Trinh Minh ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Powder Metallurgy ◽  
Porous Structure ◽  
Distilled Water ◽  
Structure And Properties ◽  
Space Holder ◽  
Hydrogen Environment ◽  
Porous Copper ◽  
Ultrasonic Process ◽  
Porosity And Permeability

In this work, the porous copper samples were produced via the powder metallurgy using NaCl as the space holder. Cu and NaCl powders were mixed by a double-cone mixing machine and then pressed into the cylindrical pellets (12 mm in diameter) at the pressure of 100 MPa. The sintering was done in a tube furnace using hydrogen environment at 900 oC for 1h. After sintering, the samples were subjected to vibration in water for 3h to remove the NaCl particles. The results showed that the porous copper has been produced and NaCl has been completely removed after the ultrasonic process in distilled water. Using NaCl space holder, the porous structure has two types of pores: the macropore induced by the removement of NaCl and the micro-pore induced by the partial sintering of Cu powders. With increase of NaCl content from 0 to 20 wt.%, the porosity and permeability of the samples increased from 24 to 58 % and from 1.53×10-13 to 12.46×10-13 m2, respectively. However, the compressive strength of the samples has a decrease with the increase of porosity resulted from the increase of NaCl content.

Mechanical Properties of Aluminium Foam by Conventional Casting Combined with NaCl Space Holder

2013 ◽  
Vol 393 ◽  
pp. 156-160 ◽  
Author(s):  
Razmi Noh Mohd Razali ◽  
Bulan Abdullah ◽  
Ismail Muhammad Hussain ◽  
Umi Kalsom Ahmad ◽  
Mohd Faizul Idham ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Energy Absorption ◽  
Size Range ◽  
Aluminium Foam ◽  
Machining Process ◽  
Water Leaching ◽  
Space Holder ◽  
Molten Aluminium ◽  
Good Energy

The purposes of this study were to determine the correlation of the aluminium foams mechanical properties in terms of the effect between its density and porosity as well as between its compressive strength and energy absorption of aluminium foam produced by space holder technique. The space holder used was NaCl particle with three different sizes and conditions. The space holders were completely filled the cavity prior pouring of molten aluminium by CO2 sand casting. Then, the samples underwent machining process to remove surface imperfection after casting, followed by water leaching in ultrasonic cleaner to remove the space holder. The higher the porosity, the lower the compressive strength but then again it acts as good energy absorption. Aluminium foam using NaCl size range of 10-15 mm has the highest energy absorption.

scholarly journals Structural and physico-mechanical characterization of closed-cell aluminum foams with different zinc additions

2018 ◽  
Vol 25 (4) ◽  
pp. 789-795 ◽  
Author(s):  
Ankur Bisht ◽  
Brijesh Gangil
Keyword(s):  
Compressive Strength ◽  
Energy Absorption ◽  
Room Temperature ◽  
Mechanical Characterization ◽  
Pure Aluminum ◽  
Zinc Content ◽  
Aluminum Foams ◽  
Static Behavior ◽  
Closed Cell

Abstract Closed-cell aluminum foams with different percentages of zinc content were successfully prepared and investigated. The foamable precursors were prepared in a pit furnace by adding calcium as thickening agent, calcium carbonate as blowing agent and different percentages (0 wt.%, 0.5 wt.% and 1 wt.%) of zinc particles at 650–750°C. The distribution of Zn elements and quassi-static behavior of the foams at room temperature were investigated. The experimental results show that Zn element is uniformly distributed in cell wall matrix. The distribution of Zn elements had a significant effect on the quasi-static compressive behavior of aluminum foams; from the results, it is obvious that zinc-containing foams possessed higher compressive strength and energy absorption capacities than pure aluminum foams. Hence, it can be concluded that increase in percentage of Zn particles helps to increase the compressive strength, plateau region and energy absorption, in addition to providing better and uniform pores.

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