New miracle material for boats? Metal that floats!!

[Rohan]

This sounds wonderful, but I'm afraid it might be like carbon fiber - too expensive for the ordinary user.



The metal that could lead to 'indestructable' warships and ultralight cars | Daily Mail Online

The metal that can float on water: Radical new material could lead to 'indestructible' warships and ultralight cars
Metal matrix composite was developed with the US Army
Alloy is turned into foam by adding strong, lightweight hollow spheres
Warship made of it will not sink despite damage to its structure
Light weight could improve fuel economy in ultralight cars
By MARK PRIGG FOR DAILYMAIL.COM
PUBLISHED: 17:40 EST, 14 May 2015 | UPDATED: 00:55 EST, 15 May 2015

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Researchers have demonstrated a new type of metal so light it can float on water.
The radical new material, called a metal matrix composite, was developed with the US Army.
A boat made of such lightweight composites will not sink despite damage to its structure.
The radical new material, called a metal matrix composite, was developed with the US Army and could be used in everything from warship to cars.
+2
The radical new material, called a metal matrix composite, was developed with the US Army and could be used in everything from warship to cars.
HOW IT IS MADE
The syntactic foam captures the lightness of foams, but adds substantial strength.
The secret of this syntactic foam starts with a matrix made of a magnesium alloy, which is then turned into foam by adding strong, lightweight silicon carbide hollow spheres developed and manufactured by DST.
A single sphere's shell can withstand pressure of over 25,000 pounds per square inch (PSI) before it ruptures—one hundred times the maximum pressure in a fire hose.
The new material also promises to improve automotive fuel economy because it combines light weight with heat resistance
Although syntactic foams have been around for many years, this is the first development of a lightweight metal matrix syntactic foam.
'This new development of very light metal matrix composites can swing the pendulum back in favor of metallic materials,' said Nikhil Gupta, an NYU School of Engineering professor in the Department of Mechanical and Aerospace Engineering and the study's co-author.
It was created by Deep Springs Technology and the New York University Polytechnic School of Engineering.
'The ability of metals to withstand higher temperatures can be a huge advantage for these composites in engine and exhaust components, quite apart from structural parts.'
The magnesium alloy matrix composite is reinforced with silicon carbide hollow particles and has a density of only 0.92 grams per cubic centimeter compared to 1.0 g/cc of water.
Not only does it have a density lower than that of water, it is strong enough to withstand the rigorous conditions faced in the marine environment.

[jongleur]

I'm thinking that the amount of this material
in the hull is insignificant wrt the rest of the
items on a "warship." Wood hulls float too,
but wooden warships have sunk after damage.

[jimbunyard]

Magnesium alloy?

[Cheechako]

Doesn't Magnesium burn readily?

[travellerw]

Originally Posted by Cheechako

Doesn't Magnesium burn readily?

When its in a solid lump its pretty hard to ignite. Many laptop components (hinges, heat pipes, ect) are made of magnesium. Not sure I would want it on a warship as I'm pretty sure an incendiary round could ignite it.

I think the exciting part of this annoucement is they have figured out how to make a strong metal foam. There have been metal foams made in the past, but they are significantly weaker than the original metal. I'm guessing these speres could be used with other metals as well, e.g. Aluminum (or Al-u-mini-um for our Aussie friends )

[Cheechako]

yeah, 25ksi not very strong for metal, but not bad... maybe 2/3 strong as soft steel?

[hellosailor]

Incoming ordnance explodes and starts that magnesium hull on fire, and it won't matter very much that the seawater has been trying to chew holes in it anyway. Sounds like a solution in search of a problem, and warships ain't it.

[mstrebe]

These hollow glass spheres have been around for a long time. I'm surprised this is news.

Fortunately there's nothing particularly difficult about this process and it results in materials that are readily cast-able, forgeable, and extrudable so it can be worked in most of the same ways as typical metals. In fact, sheet and bar stock of the stuff might actually be cheaper at quantity than solid metals, because these glass spheres are not expensive.

I'm guessing they're using magnesium because it's molten viscosity and surface tension is such that it will not cause the silicon microspheres to "clump" but rather allow them to distribute evenly throughout the liquid metal. Aluminum should be quite similar in that respect.

Magnesium would be troublesome for corrosion.

[mstrebe]

Originally Posted by Cheechako

yeah, 25ksi not very strong for metal, but not bad... maybe 2/3 strong as soft steel?

It's not really a linear comparison. These microspheres are so tiny that their breaking strength won't substantially impact the overall flexural strength of the metal. Instead, you wind up with a metal foam whose properties are based more on the thickness of the foam ligands between the spheres, which is a function of the amount of microspheres mixed into the liquid metal.

Ultimately you'll wind up with a metal that may or may not have have greater resistance to flexure but which will certainly be more brittle than the solid metal.

[anacapaisland42]

I don't know about floating metal but the experiments with "micro-etching"
that creates a metal (steel) surface that water won't "stick" on could have a lot of potential for sailors, especially racers.
Bill

Researchers at the University of Rochester announced they’ve discovered a laser-patterning technique that renders any metal surface super hydrophobic (water-repellent). So much so, in fact, the material can no longer get wet. According to Chunlei Guo, professor of optics at the University of Rochester, this imparted property could lead to some game changing, if not comic, results. “The material is so strongly water-repellent, the water actually gets bounced off,” said Guo, who is lead author of a paper describing the technique, published this week in the Journal of Applied Physics.
As described in the research paper, the process uses a femtosecond laser to etch “an array of parallel microgrooves” measuring 75 μm deep and approximately 100μm apart. The grooves increase the metal surface’s contact angle, which in turn causes water droplets to round and roll off more easily. Water droplets falling onto a treated surface, the paper reports, retain 30 percent of their kinetic energy and rebound repeatedly, like kids on a trampoline.
In addition to water-repellent, the treated metal also becomes self-cleaning, in that the repelled water picks up and removes dust and other contaminates as it rolls off. And, unlike coatings, the treatment doesn’t wear off, since the laser etching transforms the material’s surface itself with a complex, nano-scale pattern.

[jheldatksuedu]

Originally Posted by anacapaisland42

I don't know about floating metal but the experiments with "micro-etching"
that creates a metal (steel) surface that water won't "stick" on could have a lot of potential for sailors, especially racers.

And, unlike coatings, the treatment doesn’t wear off, since the laser etching transforms the material’s surface itself with a complex, nano-scale pattern.

A nano scale pattern doesn't sound very durable to me on a metal in corrosive salt water. I was also going to mention, that the hull material density has little to do with sinkability of a boat. A foam material tends to be brittle, there is less material to withstand the large stresses at the surfaces during bending.

[anacapaisland42]

Originally Posted by jheldatksuedu

A nano scale pattern doesn't sound very durable to me on a metal in corrosive salt water. I was also going to mention, that the hull material density has little to do with sinkability of a boat. A foam material tends to be brittle, there is less material to withstand the large stresses at the surfaces during bending.

BUT,
can you imagine a nano scale pattern on something like aluminum foil that one would just glue onto a hull for anti-fouling when it sacrifices
Bill

[davefrediam]

Well if the metal used is magnesium I can guarantee you it will be unsuitable for the marine environment because of corrosion issues. Give me a shout when they develop a titanium version at a practical price!

[first wind]

Originally Posted by anacapaisland42

I don't know about floating metal but the experiments with "micro-etching"
that creates a metal (steel) surface that water won't "stick" on could have a lot of potential for sailors, especially racers.
Bill

Researchers at the University of Rochester announced they’ve discovered a laser-patterning technique that renders any metal surface super hydrophobic (water-repellent). So much so, in fact, the material can no longer get wet. According to Chunlei Guo, professor of optics at the University of Rochester, this imparted property could lead to some game changing, if not comic, results. “The material is so strongly water-repellent, the water actually gets bounced off,” said Guo, who is lead author of a paper describing the technique, published this week in the Journal of Applied Physics.
As described in the research paper, the process uses a femtosecond laser to etch “an array of parallel microgrooves” measuring 75 μm deep and approximately 100μm apart. The grooves increase the metal surface’s contact angle, which in turn causes water droplets to round and roll off more easily. Water droplets falling onto a treated surface, the paper reports, retain 30 percent of their kinetic energy and rebound repeatedly, like kids on a trampoline.
In addition to water-repellent, the treated metal also becomes self-cleaning, in that the repelled water picks up and removes dust and other contaminates as it rolls off. And, unlike coatings, the treatment doesn’t wear off, since the laser etching transforms the material’s surface itself with a complex, nano-scale pattern.

there is a species of small lizard that has skin like that. water that lands on it won't wet it. it simply turns into little balls and rolls off. it is so water repellant that it can actually stand on the water.

[Stumble]

The problem with these super hydrophobic coatings and texturing on a hull is that they don't stop growth. Barnacles, slime, ect can all still attach and since you can't use both a hydrophobic coating and anti-fouling you boat will quickly look like a forest.

Unless of course you are willing to dive on it daily to wipe down the surface, which will also sand off the texturing pretty quickly.