Thursday, January 21, 2016

"The U.S. Army Wants Some Tank-Busting Silver Bullets."

We're talking about something more exotic. the slugs known as explosively formed penetrators (EFPs), which are fired by some anti-armor weapons. An explosively formed penetrator starts out as a shallow metal plate or lens, backed by an explosive charge. When the charge detonates, the plate is blasted into a streamlined, aerodynamic slug travelling at high speed over dozens or hundreds of meters. . .
While many EFPs are made of copper, in recent years the preferred metal has been a more unusual one, tantalum. Because it is twice as dense as copper, Tantalum makes a much more effective penetrator.
Tantalum is used in the manufacture of capacitors for phones, computers, and other electronics, so it is in high demand. The price can soar over $200 a pound. In addition, shaping Tantalum into an EFP liner is challenging. It has to be made into a disc, flattened in a forge, annealed at high temperature, and then "machine domed" into the right shape. That adds to the cost.
The Army's search for a more economic alternative led to silver—specifically, a new form of nanostructured silver that is as strong as steel. Metals have a crystalline structure, and the size and arrangement of these crystals affect the strength of the finished article. According to the Army, normal silver has a yield strength of 50-150 Mpa (megapascals), where nanostructured silver will have a yield strength of 250-500 Mpa. Their requirement is for silver with a strength of 300 Mpa. (For comparison, the A36 steel commonly used in the construction industry has a yield strength of 215 Mpa). They know it's possible. A paper published last year by a team at Prague's Institute of Chemical Technology in the Czech Republic describes a new method of producing high-strength nano-crystalline silver by means of "selective leaching combined with spark plasma sintering."
If this project were successful, it could lead to cheaper EFP weapons. At the moment silver costs $224 per pound, in the same ballpark as tantalum. But it's easier to manufacture with silver, which could drive down the overall cost.
New silver EFPs may not be limited to being big, cheaper tank-busters. The baguette-sized Spike missile has been tested with an EFP warhead for taking on light vehicles. The U.S. Army may never need to kill an armored werewolf, but if the occasion arises, they're have the right ammo ready to go.

8 comments:

Anonymous said...

Question for anybody that is better educated on metals than myself, if they can use copper as a EFP, why not brass? It's heavier and stronger than copper

Chiu ChunLing said...

Why can't they just put micro-beads of tungsten or something in a steel matrix backed by a steel plate? Is that really more difficult and expensive than nanoforged silver?

I grant, these are still cheaper than the enemy tanks they could kill...if we actually use them before they become obsolete. But it's still insane.

Anonymous said...

This is a HUGE BS smoke screen to cover up for the ultrahigh cost of what ever super secret do-hicky the military really wants. The whole story was utterly dependent on the readers ignorance of how the weapons systems really works. The second reason for this BS would be to get an "enemy" government to spend a few gazillion dollars to "duplicate" BS. Ether way the story is still BS.

Galaxie_Man said...

Wait....according to the anti-gun, panty-peeing hoplophobes...all the Army needs is a .50 caliber rifle to kill a tank! They can supposedly use that same scary weapon to take down helicopters, and don't they already have those?

PO'd American said...

It's not BS, do a little fact checking. Originally it was created in England and has been around a long time.

http://www.globalsecurity.org/military/systems/munitions/bullets2-shaped-charge.htm

Ed said...

Plus, perhaps if people believe there is something of value within a munition, they will disassemble and salvage the metal, just like they strip copper from live electrical lines now.

Chiu ChunLing said...

Actually, I think that Anonymous at 12:18 has a point, but is getting it backwards. The vast sums of money that go into military procurement budgets end up completely blinding the engineers working on new weapons to the utterly ludicrous expense of many of the systems they design.

Anonymous said...

Copper is plenty effective as the projectile. When you make an EFP, it's the shape of the explosive that matters, the metal can be just a flat slab. Max range is about 1000 diameters of the slab/explosive assembly. Quality of everything makes a difference.

Why don't we substitute gold as a non-toxic substitute for lead? The notion of super-expensive nano-silver as an EFP metal is definitely cover for a black budget expenditure.

EFP's are awesome against armor when compared to big dumb bomb blown-up close. This is 1930's tech made cheap by Iranians, and common knowledge among high-speed physics folks. #10 can-size is popular. Melting/casting copper is low-tech backyard industry. Assuming your supply of moldable explosive is in short supply (as mine is), EFP's scale up and down pretty well, saving you the waste of too much Big Dumb Bomb.

http://www.amazon.com/Fundamentals-Shaped-Charges-W-Walters/dp/0471621722/