Strong as steel. Atom probe tomography suggests that packing zinc and magnesium atoms together in groups of various sizes (small spots) can greatly improve the strength of aluminum alloy.
Credit: University of Sydney
Posted on 10/01/2010 3:11:46 PM PDT by neverdem
Snuffing out a cigarette butt with a 10-ton boot would be excessive, but using the equivalent on certain metals can yield amazing results. By smashing an aluminum alloy between two anvils, researchers have created a metal that's as strong as steel but much lighter. If the process can be commercialized, it could yield better components for aircraft and automobiles, as well as metal armor light enough for soldiers to wear in battle.
Aluminum's main advantage is its lightness. But the most abundant metal in Earth's crust is also a weakling: It breaks apart under loads that heavier metals such as steel shoulder easily. For decades, scientists have been looking for a way to manufacture the aluminum equivalent of titanium, a lightweight metal that's stronger than steel, but without titanium's high cost.
In the new study, an international team of materials scientists turned to an emerging metal-processing technique called high-pressure torsion (HPT). Basically, HPT involves clamping a thin disk of metal to a cylindrical anvil and pressing it against another anvil with a force of about 60,000 kilograms per square centimeter, all while turning one anvil slowly. The researchers also kept the processed samples at room temperature for over a month, in a common metallurgical process called natural aging. The deformation under the enormous pressure plus the aging alters the basic structure of metals at the nanoscale—or distances measured in billionths of a meter.
And indeed, when the team subjected an alloy of aluminum called aluminum 7075 (which contains small percentages of magnesium and zinc) to the process, the metal attained a strength of 1 gigapascal, the researchers report in the current issue of Nature Communications. That's equal to some of the strongest steels and more than three times higher than conventional aluminum. A meter-square plate of the processed alloy could withstand the weight of a fully loaded aircraft carrier.
To find out why the alloy had gotten so much stronger, the team examined samples using a technique called atom probe tomography. Resembling a combination of an electron microscope and a CT scanner, the method showed that HPT had deformed the lattice of atoms in the alloy into an unprecedented arrangement. Instead of the normal structure found in the conventional metal, HPT had created what the researchers call a hierarchical nanostructure: the size of the aluminum grains was reduced, and the zinc and magnesium atoms clustered together in groups of various sizes, depending on whether they were located inside the aluminum grains or on the edges (see photo).
Exactly how this arrangement creates stronger aluminum is unclear, says co-author Simon Ringer, director of the Electron Microscope Unit at the University of Sydney in Australia. He says the atoms at the edges of the grains seem to be bonded tightly to atoms at adjoining grain edges. Whatever the physics, he says, the hierarchical structures are "very potent for strengthening."
Ringer adds that even though the experiments produced only laboratory quantities of the superstrength alloy, the process could quickly be adapted to produce small components that require high strength but low weight, such as biomedical implants. Co-author and materials scientist Yuntian Zhu of North Carolina State University in Raleigh says there is strong incentive to scale up the process because the alloy could be useful for "many lightweight, energy-efficient applications such as aerospace, transportation, and body armor."
The experiments "have achieved remarkable strength" in a conventional commercial aluminum alloy, says materials scientist Terence Langdon of the University of Southern California in Los Angeles. The research team has also demonstrated "the exceptional capabilities provided through processing by high-pressure torsion," a technique that Langdon and others have been working with for several years.
Materials scientist Yuri Estrin of Monash University in Melbourne, Australia, calls the results exciting and agrees that the hierarchical nanostructures "appear to be crucial to the spectacular enhancement of [the alloy's] strength."
B4L8r
Cant wait for transparent aluminium......
First thing I thought of too.
Stronger...if it’s reinforced with boron fiber. :)
“Cant wait for transparent aluminium......’
Yeah! Then I’ll be able to see how much Steel Reserve is left in that big can!
It may be strong as steel, but fire will NEVER melt it.
Two comments:
1- Maybe if they squish it hard enough they can make it transparent, like on one of the Star Trek movies.
2- This reminds me a bit of “Ice Nine”, exploring phases of materials which have surprising properties... and in the case of Ice Nine, consequences.
There ya go again watching too many old movies.
LUBB
A few years back a lab in NYS was working on a substance called nitinol, a mixture of nickel and tin (I think)., the purpose of which was to approach some sort of energy output...perpetual motion...hah PM is a dead end goal so far as I know. I have heard nor read nothing about the outcome of that research. Anyone have anything on it? sd
ah, but can it make it transparent?
I wonder if this material would work to make the ribbon for the Space Elevator?
Aluminum and nanotubes can form a composite that has similar properties. Now if you can make it even harder-hmmm....
I would like to see more of that video.
Never attempt that if you have 34” inches of hair.
You’ll strangle yourself.
LOL that was my first thought too.
By smashing an aluminum alloy between two anvils, researchers have created a metal that's as strong as steel but much lighter.For the next experiment, researchers made two anvils out of the new alloy, used them to smash steel, and produced steel that was just as heavy, but no stronger than regular aluminum. Okay, no, I can't back that up.
Oh YEAH! This would be a great uses of this new type of aluminum.
If this Reardon metal ever becomes economical to produce, I expect President Thompson...uh...Obama to nationalize it too.
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