AsianScientist (Aug. 25, 2011) – An international team of researchers has created a new, super-dense version of aluminium that could lead to efficient production of new super-hard nanomaterials at a relatively low cost.
In their paper, published today in Nature Communications, the group described a method of producing body-centred-cubic aluminium, which is 40 percent more dense than normal aluminium.
Although super-hard aluminium was predicted to exist more than 30 years ago, it had never before been observed.
Prof. Andrei Rode from the Laser Physics Center at Australian National University, describing the process of creating the super-dense material, said:
“We demonstrated that it is possible to create extreme pressure and temperature conditions in table-top laboratory experiments using an extremely short laser pulse to create a huge concentration of energy in a very short time and in a very small sub-micron volume inside a sapphire crystal, which is aluminium oxide.”
“This experiment resulted in something like a micro-explosion which turned the aluminium to a plasma state that swelled but had nowhere else to go, creating gigantic pressure and dramatic changes in surrounding material properties and producing unfamiliar x-ray spectral lines,” he said.
At first, the researchers had trouble identifying the material that was formed from these ultrafast microexplosions. But a “crazy idea” to compare any possible aluminium crystal phases to the observed spectra led to the discovery that this was a phase of aluminium that had never been observed.
The idea was considered crazy as it contradicted a conventional wisdom that aluminium surrounded by oxygen must be oxidised in normal condition.
According to Prof. Saulius Juodkazis, a team member from Swinburne University of Technology, the discovery could significantly advance applications which rely on nanostructured materials.
“Using this focused laser technique, we may now be able create a range of superdense metals that have extraordinary properties. The creation of superdense silver or gold, for example, could lead to many new possibilities for bio-sensing and plasmonics,” said Juodkazis.
He said the discovery was also likely to catch the attention of earth and climate scientists.
“By examining the mechanical and electrical properties of this type of material, we may be able to gain a greater understanding of the electrical conductivity of the interior regions of the planet. This is particularly important in the context of global climate change observed over long geological time spans,” Juodkazis said.
The article can be found at: Vailionis A (2011) Evidence Of Superdense Aluminium Synthesized By Ultrafast Microexplosion.