[DeTomaso] NPC: but a bit of metallurgy to make your cars lighter

[Larry-Ohio Time Corp]

Aluminum is nice and light, but as an easily crushable soft drink can shows,
that comes at the cost of strength. By introducing faults into the metal's
crystalline structure, researchers at Purdue University have now developed
new aluminum alloys that are about as strong as stainless steel, and they
could be put to work in corrosion-resistant coatings.



On the microscopic level, metals are made up of crystal atoms in repeating
cycles of layers stacked on top of each other. A "stacking fault" occurs
when a layer is missing from the pattern, and two layers of these faults are
known as "twin boundaries" or "nanotwins." When these faults create a
structure that repeats over nine layers, it's called a 9R phase.

These stacking faults can actually make a material stronger, so Purdue
researchers wanted to introduce both nanotwins and 9R phase into aluminum.
The problem is that the metal has a "high stacking fault energy" -
essentially, that means aluminum tends to correct the faults itself.

"It has been shown that twin boundaries are difficult to be introduced into
aluminum," says Xinghang Zhang, an author on two studies describing the new
material. "The formation of the 9R phase in aluminum is even more difficult
because of its high stacking fault energy. You want to introduce both
nanotwins and 9R phase in nanograined aluminum to increase strength and
ductility and improve thermal stability."

The scientists invoked 9R phase in the material using two different
techniques. One was "shock-induced," created by using a laser to bombard
ultrathin sheets of aluminum with particles of silicon dioxide.

"Here, by using a laser-induced projectile impact testing technique, we
discover a deformation-induced 9R phase with tens of nanometers in width,"
says Sichuang Xue, lead author of this study.

 <javascript:void(0)> 

The second study used a process called magnetron sputtering to introduce
iron atoms into the aluminum's crystal structure. This aluminum-iron alloy
was found to be one of the strongest ever made, and the team says the
process could be scaled up to an industrial scale, for eventual applications
as corrosion-resistant coatings for electronic devices and vehicles.

"These results show how to fabricate aluminum alloys that are comparable to,
or even stronger than, stainless steels," says Zhang. "There is a lot of
potential commercial impact in this finding."

The shock-induced alloy was described in research published in the journal
<https://www.nature.com/articles/s41467-017-01729-4> Nature Communications,
while the magnetron sputtering technique was published in
<https://doi.org/10.1002/adma.201704629> Advanced Materials.

Larry - Cleveland

 

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   Aluminum is nice and light, but as an easily crushable soft drink can
   shows, that comes at the cost of strength. By introducing faults into
   the metal's crystalline structure, researchers at Purdue University
   have now developed new aluminum alloys that are about as strong as
   stainless steel, and they could be put to work in corrosion-resistant
   coatings.

   [cid:image002.gif at 01D398F4.F0679A00]

   On the microscopic level, metals are made up of crystal atoms in
   repeating cycles of layers stacked on top of each other. A "stacking
   fault" occurs when a layer is missing from the pattern, and two layers
   of these faults are known as "twin boundaries" or "nanotwins." When
   these faults create a structure that repeats over nine layers, it's
   called a 9R phase.

   These stacking faults can actually make a material stronger, so Purdue
   researchers wanted to introduce both nanotwins and 9R phase into
   aluminum. The problem is that the metal has a "high stacking fault
   energy" - essentially, that means aluminum tends to correct the faults
   itself.

   "It has been shown that twin boundaries are difficult to be introduced
   into aluminum," says Xinghang Zhang, an author on two studies
   describing the new material. "The formation of the 9R phase in aluminum
   is even more difficult because of its high stacking fault energy. You
   want to introduce both nanotwins and 9R phase in nanograined aluminum
   to increase strength and ductility and improve thermal stability."

   The scientists invoked 9R phase in the material using two different
   techniques. One was "shock-induced," created by using a laser to
   bombard ultrathin sheets of aluminum with particles of silicon dioxide.

   "Here, by using a laser-induced projectile impact testing technique, we
   discover a deformation-induced 9R phase with tens of nanometers in
   width," says Sichuang Xue, lead author of this study.

   The second study used a process called magnetron sputtering to
   introduce iron atoms into the aluminum's crystal structure. This
   aluminum-iron alloy was found to be one of the strongest ever made, and
   the team says the process could be scaled up to an industrial scale,
   for eventual applications as corrosion-resistant coatings for
   electronic devices and vehicles.

   "These results show how to fabricate aluminum alloys that are
   comparable to, or even stronger than, stainless steels," says Zhang.
   "There is a lot of potential commercial impact in this finding."

   The shock-induced alloy was described in research published in the
   journal [1]Nature Communications, while the magnetron sputtering
   technique was published in [2]Advanced Materials.

   Larry - Cleveland

References

   Visible links
   1. https://www.nature.com/articles/s41467-017-01729-4
   2. https://doi.org/10.1002/adma.201704629

   Hidden links:
   4. javascript:void(0)
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