
'Metallic wood' has the strength of titanium and the density of water - LinuxBender
https://www.sciencedaily.com/releases/2019/01/190128125314.htm
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logfromblammo
The problem with metamaterials that have interesting macro-scale properties
has always been manufacturing them cost-effectively and in quantity.

It hardly matters if this stuff has a better strength-to-weight ratio than
titanium if it also costs 1000 times as much to make an airplane wing out of
it.

"Metallic wood" is a very misleading term, too. The material in question is
nickel with a cellularized structure resembling wood, rather than a cellulose
variant that has undergone some process that bestowed metal-like properties
upon it. A more accurate term would have been "xyloid metal" or "ligneous
metal".

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jandrese
Plus other factors like the failure modes or how it fatigues in use or how
badly it is affected by corrosion or unfortunate thermal constraints. There
are plenty of super light and strong but materials that are not suited for use
in vehicles or large structures due to a practical limitation of the
substance.

Nobody wants to build an airliner wing that is 70% of the weight of a regular
wing, but also explodes into a million tiny pieces when it suffers a bird
strike.

~~~
MrLeap
Nickel tends to be very corrosion resistant. Though these properties are
probably diminished by the increased surface area of the porous topology.

I run a small forge. Every alloy I've used will corrode way faster if it's not
been finished smooth. I can only imagine how fast a metal (even nickel) foam
oxidizes.

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michaelbuckbee
Interesting, seems like nanoscale metal foam:
[https://en.wikipedia.org/wiki/Metal_foam](https://en.wikipedia.org/wiki/Metal_foam)

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dschuetz
The fact alone that it's lighter than titanium is a big deal. That's great.

But, too bad that nickel is toxic as hell, and many people are allergic to it.
So, I guess it's the biggest trade-off when compared to titanium.

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IshKebab
"Some people have an allergic reaction to it" is hardly "toxic as hell".

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Kalium
You're right!

Let me see if I can clarify the original point. Nickel is both toxic when
ingested and often a contact allergen. Thus the two points are independently
true of one another and in no way contradictory.

I hope this has been helpful.

~~~
njarboe
What generally happens to kids that find a US nickel on the ground/floor and
swallow it without their parents notice? This must have happened a million of
times.

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wincy
Not a kid, but I’m allergic to nickel and my daughter threw some quarters in
my bed. I didn’t realize it and slept with a quarter burning a hole into my
side. I woke up with a quarter-shaped rash that lasted about a week.

~~~
sitkack
This is like the reverse of a super power.

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Isamu
I guess so called because "woody metal" sounds weird?

>"The reason we call it metallic wood is not just its density, which is about
that of wood, but its cellular nature," Pikul says. "Cellular materials are
porous; if you look at wood grain, that's what you're seeing? -- parts that
are thick and dense and made to hold the structure, and parts that are porous
and made to support biological functions, like transport to and from cells."

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droopyEyelids
What kind of world do we live in where Sciencedaily.com uses phrases like
"titanium, which is as strong as steel but about twice as light"

Twice as light.

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thfuran
Fine, it weighs two times less.

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someone454
It’s half the mass ;)

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marcosdumay
It's confusing. I can as easily conclude it's either 1/2 or 1/3 of the mass.

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thfuran
Or we could have finally managed negative mass.

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RobertoG
It would be interesting to know why they choose nickel.

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MrLeap
Nickel tends to be corrosion resistant. Oxidation is a probabilistic sort of
thing. The higher the surface area, the higher chance of corrosive cascades. A
metal sponge has significantly higher surface area than the equivalent mass of
polished bar stock.

I bet if they did the same thing with iron, a drop of peracetic acid on it
would make it go "FOOF!".

Actually that might still work on the nickel.

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ph0rque
I wonder if one could 3D-print such structures?

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egypturnash
"The struts in the researchers' metallic wood are around 10 nanometers wide,
or about 100 nickel atoms across. Other approaches involve using 3D-printing-
like techniques to make nanoscale scaffoldings with hundred-nanometer
precision, but the slow and painstaking process is hard to scale to useful
sizes." \- TFA

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keepper
Lignumified metal? :)

( lignum is wood/timber in Latin )

~~~
nardi
Lignified*, which is actually a word, “to make woody”

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ohiovr
What kind of strength? Every aspect? Super. If it doesn’t have the stiffness
of titanium it isn’t really as strong.

Edit ok sorry that I confused stiffness with strength. Sorry my lay opinion
was factually incorrect

If it turns out to be brittle it can’t be used in the wings. That is my lay
opinion on making an aircraft.

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lenticular
Stiffness is usually not considered strength. Strength, whether in
compression, tension, or shear, is usually defined as the load it can handle
without plastic deformation or fracture. Elastic deformation is by definition
reversible once the load is removed.

Titanium actually isn't that stiff, either. It's quite a bit more flexible
than steel. New martensitic steel alloys can be close to a match for the best
titanium alloys for strength/weight ratio as well.

Since this material is less dense, it should provide better stiffness for
weight, since thicker members can be constructed with the same weight. Much
like how aluminum bicycles have much larger tubes than steel ones, to make up
for the greater elastic flexibility of aluminum.

