Hypothetical question: diamond armor

[Marcello]

Hypothetical question: if one could cheaply manufacture almost flawless diamonds (meaning with very little amounts of impurities, cracks) of any desired size would they be useful as an armor material for tanks? And if so

1)How would they be better integrated into a tank protection scheme:large plates sandwitched between steel layers? Or would small diamonds embedded in a matrix be better? Some other arrangement?

2)Roughly speaking what sort of resistance could such protection schemes offer against moderns APFSDS and HEAT rounds (es 1cm of diamond plate equivalent to Xcm of RHA against sabots)

[Mobius]

That's really hard to say. They'd have to run tests. Carbon is a light material so something with extra mass should be combined with it to absorb the momentum while the carbon bonds absorb KE.

Awhile back I proposed using a heavy metal ion surrounded by carbon atoms in a bucky lattice as a basis for armor.

[TTK Ciar]

Here is an index into my tanknet archives for previous discussions which mention "diamond":

 

http://aux.ciar.org/ttk/mbt/tanknet/IX/di/_diamond.html

 

There are some useful references in there.

 

-- TTK

[Guest JamesG123]

Short answer is "yes", but not in the way you are thinking.

 

You wouldn't want a plate of diamond or some sort of encrusted matrix. You would want to grow them into mono-molecular strands and then embed them into some kind of composite. Sort of like a super kevlar.

[Nian]

Polycrystalline diamond appears to be very effective at interface defeat. According to a post from last year by Paul Lakowski, it also has a high thickness efficiency (and mass efficiency, as Syndie is less dense that titanium).

[Doug97]

What about using diamond chunks instead of ceramic ones? Aren't they supposed to turn as the porojectile hits causing it to yaw?

 

[Marcello]

Polycrystalline diamond appears to be very effective at interface defeat.  According to a post from last year by Paul Lakowski, it also has a high thickness efficiency (and  mass efficiency, as Syndie is less dense that titanium).

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Any guesses about Syndie performance against shaped charges?

[Nian]

Any guesses about Syndie performance against shaped charges?

344831[/snapback]

Just looking at its density (4,100 kg/m^3), I'd expect thickness efficiency of about 0.72, while its mass efficiency would be about 1.38, but I don't have any data from actual tests or simulations.

[Marcello]

Just looking at its density (4,100 kg/m^3), I'd expect thickness efficiency of about 0.72, while its mass efficiency would be about 1.38, but I don't have any data from actual tests or simulations.

348203[/snapback]

 

Interesting.So if you are correct it would offer susbstantially less resistance to HEAT than to APFSDS.

[EVladV2]

you also have to remember that diamonds tend to fracture easily.

 

the best way was already suggested here - diamond-carbon nano-fiber. Weave it like kevlar and apply layers upon layers of it.

 

This will have fantastic heat resistance and kinetic resistance as well.

 

what about amorphous metal?

[Paul Lakowski]

you also have to remember that diamonds tend to fracture easily.

 

the best way was already suggested here - diamond-carbon nano-fiber.  Weave it like kevlar and apply layers upon layers of it.

 

This will have fantastic heat resistance and kinetic resistance as well.

 

what about amorphous metal?

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The key to the success of most modern armor concepts is not just the material properties but the way they interact with other elements of the armor 'system' and that interaction with the impacting projectile and all its strengths and weakness.

[Nian]

you also have to remember that diamonds tend to fracture easily.

Ceramics also break easily; I imagine Syndie would be confined in a similar manner. I wonder if the shattered diamond would cut up the confining materials, though.

what about amorphous metal?

I think amorphous materials tend to make poor armor against KE threats, but I'm not sure if that's because of their amorphous structure or just the particular materials that have been tested.

 

Paul, could you share where you found Syndie's thickness efficiency? I'd love to read more about this.

[Paul Lakowski]

Ceramics also break easily; I imagine Syndie would be confined in a similar manner.  I wonder if the shattered diamond would cut up the confining materials, though.I think amorphous materials tend to make poor armor against KE threats, but I'm not sure if that's because of their amorphous structure or just the particular materials that have been tested.

 

Paul, could you share where you found Syndie's thickness efficiency?  I'd love to read more about this.

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I found the article. I will see if I can find it on Science Direct and upload it to the database site...

 

http://uploads.armsandarmornet.org/files.xml

 

Article is Int.J.Impact Engng vol 20 pp 259-275 "Impact of metallic Projectiles on ceramic targets: transition between interface defeat and penetration". Lunberg etal 2000.

 

 

OK found the article here it is....

 

http://uploads.armsandarmornet.org/IJIE,Vo...p%20259-275.pdf

[EVladV2]

think amorphous materials tend to make poor armor against KE threats, but I'm not sure if that's because of their amorphous structure or just the particular materials that have been tested.

 

 

Uhm, I have a friend who is materials engineer and he had to say some amazing stuff about true high stress amorphous steel. He said that it would be an awesome protection against KE - as long as you don't rely on it solely, composite armor is a way to go!

 

amorphous tungsten?

[Doug97]

AGGREGATED DIAMOND NANORODS!

 

How can you go wrong with a name like that?

 

I also noted that boron nitride is harder than boron carbide, yet isn't used in armour ... why is that?

Edited August 7, 2006 by Doug97

[TTK Ciar]

I also noted that boron nitride is harder than boron carbide, yet isn't used in armour ... why is that?

Boron nitride is very, very difficult to make and to sinter together from a powder into whole pieces (like tile shapes). Most countries don't have the industrial base for producing BN, and those that do don't want to go through the expense. Sintered BC is quite expensive enough ($600 or so per pound).

 

Note that even though America's military uses BC in many applications (including body armor SAPI plates and helicopter cockpit armor), the M1 Abram's ceramic armor component seems likely to be silicon carbide. This seems likely to be due to its extremely high compressive strength, and its demonstratedly superior interface-defeat properties. Army Research Lab papers, written over a decade ago and recently declassified, show that the ARL has put nontrivial time and effort into researching interface-defeat specifically using silicon carbide. Silicon carbide has a higher absolute compressive strength than BN, so even if BN were more available I suspect Abrams would continue to use SC in its armor.

 

Silicon Carbide Properties

 

Regarding amorphous metals in armor: The amorphous steels I have seen are extremely strong, but brittle, making for low toughness (and toughness is important in an armor system -- when Very Hard Steel is used in an armor system, it is laminated between layers of less-hard steel to make up for its brittleness, and amorphous steels are even more brittle than VHS). They're more comparable to ceramics than they are to metal -- except that they're not quite as strong as AO, and about twice as dense! I'm not sure how well they compare price-wise, so maybe they could be used as a low-cost alternative to ceramics, but I doubt it. Not when MMC composites are cheap and easy (and proven).

 

-- TTK

[EVladV2]

amorphous steel is brittle yes, but like i said, don't rely solely on it. I envision amrophous steel, like you said Ciar, to be used as laminate. Quite frankly i think it would make great 'epidermis' of tank armor as it has ability to rapidly dissipate heat-related energy, and although it will shatter under SABOT rounds, it will provide enough 'resistance' to stop the round from coming through the rest of the layers.

[Doug97]

AMORPHOUS ALLOY SURPASSES STEEL AND TITANIUM

 

If it's hard but brittle how about using it instead of face-hardened steel for the strike face?

[wooki]

Hypothetical question: if one could cheaply manufacture almost flawless diamonds (meaning with very little amounts of impurities, cracks) of any desired size would they be useful as an armor material for tanks? And if so

1)How would they be better integrated into a tank protection scheme:large plates sandwitched between steel layers? Or would small diamonds embedded in a matrix be better? Some other arrangement?

2)Roughly speaking what sort of resistance could such protection schemes offer against moderns APFSDS and HEAT rounds (es 1cm of diamond plate equivalent to Xcm of RHA against sabots)

344321[/snapback]

Ahhh, the penny drops...but...

 

When you design armor you need to do so in such a way as to take best advantage of the materials within the suite.

 

Diamond is hard, About 4 times harder than SiC (which is dramatic) and at least 2 times harder than CBN. So if you were going to utilize diamond you would do so in such a way as to take advantage of the hardness.

 

The mention of Amorphous metal. As a rule of thumb making something amorphous makes it 3 times stronger than the crystaline material. So amorphous ceramics (not metals) are extremely attractive as they can become like steel in strength and retain some degree of hardness.

 

So to purely speculate; (for example) an amorphous diamond coating on a flier plate in your run of the mill ERA would have dramatic effect and probably allow you to reduce the weight of said flier plate.

 

I'll leave it up to you guys to speculate on the rest.

 

Cheers

 

W

[TTK Ciar]

Boron nitride is very, very difficult to make and to sinter together from a powder into whole pieces (like tile shapes). Most countries don't have the industrial base for producing BN, and those that do don't want to go through the expense. Sintered BC is quite expensive enough ($600 or so per pound).

Yesterday I was researching material costs and found that the more common price for sintered boron carbide in bulk is about $270/pound.

 

I've been using the $600/pound estimate for a few years now, based on published contract information by Ceradyne, on the assumption that the government would get a good deal from ordering massive quantities, an assumption which seems to be wrong .. either Ceradyne is expensing other things in addition to their BC SAPI plates in those contracts, or the american army is paying ~2x the going rate for their SAPI plates! :-/

 

-- TTK