Aluminum foam is used for applications that requires high level of energy and sound absorption characteristics. UiTM researchers have developed an innovative process to make high strength cellular aluminium foam with help from some salt.
Aluminium foam exhibits unique properties when compared to its dense form, particularly its lightweight characteristics. Generally, the foam can be divided into two categories; closed cell and open cell, both have different characteristics and applications.
The features of the closed cell are, the pores structure is isolated and they are not connected to each other. This type of aluminium foam is suitable for application that requires high level of energy and sound absorption characteristics. It has been used widely in many structural parts, particularly in areas exposed to high damping capacity, for example in the automotive front bumper component.
Meanwhile, the open cell, owing to greater level of connectivity of the pores, the structure has been accepted and used in thermal management applications. One such promising application is as a heat exchanger, particularly as a cooling medium to transfer heat, due to the development of its porous structure, which provides greater surface area, thus, enabling improved heat transfer efficiency. Producing a combined structure of open and closed cell in one volume component appears to be a difficult process due to the different processing techniques involved and their individual limitations.
Therefore, in this study, an innovative processing route for high strength cellular aluminium foam (CAF) by integrating porous and dense structures is presented. The CAF is well known as a light-weight product exhibiting high level of inter-connected porosity which is very useful as a thermal management application, particularly as a heat transfer or cooling medium. However, the level of strength for the CAF is not really promising when it is subjected to high impact; thus, limit its potential application, particularly in the automotive industry.
Subsequently, an alternative route by integrating dense and porous structure has been investigated. The solid aluminium at the centre acts as a pillar providing excellent strength for the surrounding foam structure. The product has demonstrated functionally graded properties which is possible for applications that require both properties of heat transfer and high strength.
The product was fabricated using infiltration of NaCl space holder combined with central solid aluminium foam. It is well known that NaCl has a greater melting point than that of aluminium. Therefore, when aluminium melts, the liquid fills the interstitial spaces between the NaCl grain. Prior to melting, the NaCl is sieved according to the desired porous structure.
The materials (NaCl, central aluminium core and dense Aluminium ingot) are placed in the cylindrical steel mould and heated at temperature range between 670 and 700oC. The NaCl is placed at the bottom mould with aluminium central pillar and bulk Aluminium placed at the top of NaCl so that after the aluminium turns into liquid, it penetrates along the interstitial spaces between NaCl. Upon solidification, the part is removed from the mould and further machining is carried out to remove surface roughness caused by the solidification process. The part is then leached in an ultrasonic water bath in order to remove the NaCl completely.
The final product is the cellular aluminium foam exhibiting excellent interconnected pores structure with dense central pillar. The central solid pillar provides extra strength for the surrounded foam structure. The foams structure produced was examined for its density, porosity and strength by compression test. Thermal conductivity was also carried out to investigate the effect of space holder size and the NaCl fractions on the final properties.
MUHAMMAD HUSSAIN BIN ISMAIL
Faculty of Mechanical Engineering
University Teknologi MARA, Malaysia
University Teknologi MARA
Improved Performance thanks to Reduced Weight
24.07.2017 | Technische Universität Chemnitz
New Headlamp Dimension: Fully Adaptive Light Distribution in Real Time
29.06.2017 | Universität Stuttgart
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
21.08.2017 | Materials Sciences
21.08.2017 | Health and Medicine
21.08.2017 | Materials Sciences