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 The car of the future – sleeper cars and travelling offices too?
18.06.2018 | Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO

nachricht Self-driving cars for country roads
07.05.2018 | Massachusetts Institute of Technology, CSAIL

All articles from Automotive Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>