Physicists find fractal boundaries in crystals

Sep 03, 2010 By Anne Ju
The top two images are two views of a computer-simulated fractal wall pattern after strain. The bottom two are micrographs taken from a single copper crystal and single aluminum crystal after strain.

Blacksmiths make horseshoes by heating, beating and bending iron, but what's happening to the metal's individual atoms during such a process? Cornell researchers, using computational modeling, are providing new insight into how atoms in crystals rearrange as the material is bent and shaped.

The researchers made computer-synthesized models of what such metals as aluminum and look like at the atomic level while being stretched, heated and cooled. They simulated how crystals, whose start in a regular grid, transform as they are bent into different shapes.

Such new theories could lead to a better understanding of structural materials, from buildings to bridges, to make them less susceptible to tearing or breaking.

"We're really at the beginning stages of trying to develop a systematic theory of how materials evolve as we vary strain and temperature," said James Sethna, Cornell professor of physics, who leads the research.

The work is published in the Sept. 1 edition (Vol. 105 Issue 10) of , a publication of the American Physical Society.

When a single crystal is bent, portions of the crystal shift and create defects in the lattice called dislocations. The researchers found that their crystals exhibited starkly contrasting properties depending on temperature.

When hot were bent, the dislocations arranged into grain boundaries, which are the places where lattice planes suddenly tilt. At low temperatures, the dislocations formed self-similar, random patterns known as fractals.

Explore further: Desirable defects

Related Stories

Quasicrystal mystery unraveled with computer simulation

Mar 06, 2008

The method to the madness of quasicrystals has been a mystery to scientists. Quasicrystals are solids whose atoms aren't arranged in a repeating pattern, as they are in ordinary crystals. Yet they form intricate patterns ...

Paving the Way for Crystal Growth

Mar 07, 2007

In order to study the properties of LBCO superconductors, scientists need to produce large, single crystals of the material - a difficult task that wasn't possible until recently. At the state-of-the-art crystal ...

Recommended for you

Bringing high-energy particle detection in from the cold

10 hours ago

Radiation detectors, which monitor high-energy particles such as those produced by nuclear decay and cosmic radiation, are being used increasingly in medical imaging, petroleum well logging, astronomy and ...

Artificial muscles created from gold-plated onion cells

10 hours ago

Just one well-placed slice into a particularly pungent onion can send even the most seasoned chef running for a box of tissues. Now, this humble root vegetable is proving its strength outside the culinary ...

Image: Into the depths of the electromagnetic spectrum

11 hours ago

It can be difficult in our everyday lives to appreciate the extraordinary range of wavelengths in the electromagnetic spectrum. Electromagnetic radiation—from radio waves to visible light to x-rays—travels ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

Kedas
5 / 5 (1) Sep 05, 2010
If they say that a and c is a match then they need glasses.
julesruis
not rated yet Sep 06, 2010
For more information about fractals, see:
http://www.fractal.org

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.