Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanocomposites toughen up

29.09.2014

An alternative fabrication route improves the properties of aluminum-based nanocomposites with great potential for vehicles of the future

One challenge in producing strong, elastic and hard-wearing nanocomposites is obtaining an even distribution of the nanoparticles in the metal matrix. Now, researchers at A*STAR have used a process known as friction stir processing (see image) to produce an evenly distributed mix of nanosized aluminum oxide (Al2O3) particles in aluminum1. Their technique is a viable new method for manufacturing nanocomposites and has exciting potential for the car, space and defense industries.


Schematic diagram of friction stir processing, a method used to improve the hardness and tensile strength of aluminum-based nanocomposites.

Copyright : © 2014 A*STAR Singapore Institute of Manufacturing Technology

“Current powder metallurgy or liquid processing methods fail to achieve uniform processing,” says research leader Junfeng Guo, who is from the A*STAR Singapore Institute of Manufacturing Technology.

Guo’s team drilled hundreds of 1-millimeter-diameter holes into the surface of a thin sheet of an aluminum alloy. They then injected a slurry of aluminum oxide nanoparticles into the holes and heated the sheet in an oven. After cooling the sheet, the team plunged a rotating tool into it — this is the friction stir processing step. The friction generated between the tool and the sheet caused the material to plasticize. The tool was moved around to ensure that the entire sheet was plasticized.

Placing the nanoparticles in the sheet prior to the friction stir processing step significantly increased the concentration of nanoparticles in the composite. “It also reduced the amount of airborne particles produced during powder placement and friction stir processing,” explains Guo.

The team used scanning electron microscopy to check two key properties that influence the strength of nanocomposites. They first demonstrated that the nanoparticles were uniformly dispersed, which means the material has no weak points. They also found that the grains or crystals of the aluminum matrix that recrystallized after being plasticized were extremely small; smaller aluminum matrix grains can flow past each other more smoothly than larger particles, enhancing the strength of the material.

By measuring the grain size after performing friction stir processing with and without the Al2O3 nanoparticles, the team showed that the nanoparticles contributed to the reduction in grain size.

The best nanoparticle distribution and smallest aluminum alloy grains were obtained after passing the rotating tool through the sheet four times. The team then demonstrated that the composite made in this way had significantly improved hardness and tensile strength compared to untreated aluminum alloy sheets.

“We plan to continue this research to further improve the mechanical and thermal properties as well as the wear resistance of the nanocomposites,” says Guo. “Eventually, we aim to commercialize our technology to aid local industry.”


Reference:
Guo, J. F., Liu, J., Sun, C. N., Maleksaeedi, S., Bi, G. et al. Effects of nano-Al2O3 particle addition on grain structure evolution and mechanical behaviour of friction-stir-processed Al. Materials Science and Engineering: A 602, 143–149 (2014) |

Associated links

A*STAR Research | Research SEA News
Further information:
http://www.researchsea.com

More articles from Automotive Engineering:

nachricht 3D scans for the automotive industry
16.01.2017 | Julius-Maximilians-Universität Würzburg

nachricht Improvement of the operating range and increasing of the reliability of integrated circuits
09.11.2016 | Technologie Lizenz-Büro (TLB) der Baden-Württembergischen Hochschulen GmbH

All articles from Automotive Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>