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My version of a tank uses reinforced depleted uranium as armor plating, however it was recently attacked by a large dragon which managed to crunch, and chew off a piece of it in one big bite.

What kind of material could allow the dragon tooth to penetrate into the tank's armor, and is it possible to duplicate the tooth using modern science? Think of Chobham armor.

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    $\begingroup$ Why depleted uranium in an armor, exactly? $\endgroup$
    – Mołot
    Commented Dec 17, 2016 at 13:37
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    $\begingroup$ @Mołot Because it's heavy (helps against kinetic energy projectiles). But it's used in composites only as far as I know, with Uranium being the heavy part and something else supplying hardness. Are you using pure Uranium? Because other than being heavy, I don't think it has much advantage and can probably be pierced fairly easily. $\endgroup$
    – Nobody
    Commented Dec 17, 2016 at 14:03
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    $\begingroup$ Depleted uranium is not what makes armor strong, as it has poor mechanical characteristics. Steel and ceramics give the armor its hardness and strength. Depleted Uranium is used in because of its high density gives it better ability to resist kinetic energy penetrators i.e. sabot rounds. Unless your dragon is firing its teeth into the tank at several times the speed of sound, the primary stresses it is putting on the tanks are the shear and crushing forces of its jaws. In that case, uranium is about as useful as butter compared to the high strength steels that encase it. $\endgroup$
    – kingledion
    Commented Dec 17, 2016 at 14:37
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    $\begingroup$ I take it "unobtanium" or simply "dragon tooth enamel" is not an acceptable answer? $\endgroup$
    – SRM
    Commented Dec 17, 2016 at 15:43
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    $\begingroup$ Are we assuming that the tank doesn't have any possibly-very-dangerous-to-a-dragon explosive reactive armor? $\endgroup$
    – Timpanus
    Commented Dec 18, 2016 at 13:34

6 Answers 6

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Before we get into teeth, note that your dragon will need some really, really strong muscles (and jaw bones) in order to take a bite out of a tank. Perhaps a "how could dragons have strong jaw muscles" question is in order.

According to the comments, depleted uranium is helpful against projectiles, but it won't do much against the compression from dragon teeth. It is usually used with steel or another alloy, however, so now the question becomes what can pierce steel effectively.

Let's use the hardness of steel and a handy unit converter, because for a quick chomp and pierce, tensile strength alone will not matter. While some of these materials may shatter if you put too much pressure on them, they are adequate for puncturing and tearing if you make them sharp enough.


Tungsten Carbide

Hardness

Some of the strongest heat-treated steel will measure at about 444 on the Vickers hardness scale, while tungsten carbide measures in at around 2242! Alternatively, using the Mohs hardness scale, steel is at around a 7, while tungsten carbide measures 9.

Organic use

It is difficult for a dragon to have tungsten teeth for several reasons:

  • Acquiring tungsten in abundance requires a really weird diet
  • Processing the elements to create an alloy requires extreme conditions (if they breathe fire, I guess this is plausible)
  • Tungsten may be toxic

A possible workaround could include dipping teeth of another material into molten metal, although I doubt molten tungsten carbide exists in nature.


Carbon Steel

Hardness

It's hard to find quantitative data to compare the hardness of carbon steel to regular steel, but note that as the carbon content increases, strength increases - so these teeth will likely be stronger than the tank material.

Organic use

It is difficult for a dragon to have carbon steel teeth because:

  • Acquiring steel in abundance requires a really weird diet
  • Processing the elements to create an alloy requires extreme conditions (if they breathe fire, this may be plausible)

A possible workaround could include dipping teeth of another material into molten metal, although I doubt molten carbon steel is easy to find in nature.


Chromium

Hardness

Chromium has a Vickers hardness of 1060 MPa, compared to steel's reasonable maximum of 444. It would definitely get the job done.

Organic use

Many yeasts have a high chromium content. While some forms of the element may be toxic, it's reasonable to think that dragons could consume animals that rely on this yeast - or they could cultivate the yeasts themselves.


Titanium

Hardness

Titanium has a Vickers number of 830–3420 - higher than that of most steel - so you should be all set.

Organic use

Organic titanium compounds are found in some natural reactions. These could occur in the prey of your dragons, or their prey's prey; with some more work and possibly some handwaving you could construct titanium teeth.


Diamond

Hardness

Diamonds are considered to be one of the strongest natural substances - with a 10 on the Mohs hardness scale, compared to a 6-7 for most steel. These are the most ideal teeth you could have.

Organic use

No organic processes can create, or have created, diamonds. However, since dragons tend to hoard gemstones (and some consume them) it's reasonable to think that a dragon's body could arrange diamond particles and bind them with an alloy to make semi-diamond teeth.


Ruby

Hardness

At a measure of 9 on the Mohs scale, rubies are significantly harder than steel.

Organic use

Similarly to diamonds, no organic processes can create, or have ever created, rubies. However, since dragons tend to hoard gemstones (and some consume them) it's reasonable to think that a dragon's body could arrange ruby particles and bind them with an alloy to make semi-ruby teeth.


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  • $\begingroup$ This was getting long but see also silicon carbide and boron. $\endgroup$
    – Zxyrra
    Commented Dec 17, 2016 at 16:42
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    $\begingroup$ I'm very new to material properties, but isn't toughness also extremely important? For example, diamonds are extremely hard, but very brittle, so they can break more easily in certain circumstances. $\endgroup$ Commented Dec 17, 2016 at 22:51
  • $\begingroup$ Also, though, there is a new form of man-made diamond called Lonsdaleite that might be of use, since it is much harder than normal diamond. But I don't know about it's other properties. $\endgroup$ Commented Dec 17, 2016 at 22:52
  • $\begingroup$ @ThomBlairIII It is, although I reasoned when writing this that if the teeth are sharp they will puncture instead of shattering $\endgroup$
    – Zxyrra
    Commented Dec 17, 2016 at 23:29
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    $\begingroup$ @Zxyrra true. Another thing to consider that may whittle down your options is that a dragon attacking a modern tank would really need teeth tough enough to handle reactive armor, especially the explosive reactive variety $\endgroup$
    – Timpanus
    Commented Dec 18, 2016 at 15:53
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The dragon's jaws need to be strong enough to crush the tank, and its teeth need to be strong enough to resist not shattering at the tremendous pressure which this will require. Furthermore, the bone structure itself needs to be strong enough to hold the teeth in place, as well as not break under that same pressure. The tissue in its mouth must also resist severe damage from the metal shards, and sharp edges which will be pressing into it.

Last but not least, the dragon must be powerful enough to lift a main battle tank off of the ground, in its jaws, so that it can move it in an optimal position for crushing.

Since we have long left behind the rolling plains of realism, and entered the rocky valley of "this must now be solved with magic", I do believe that your dragon should be made of unobtainium.

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  • $\begingroup$ I'd say more reasonably he could just have the teeth be made of something from Zxyrra's answer. How that happens is via a natural and simple chemical reaction using unobtanium and handwavium. The teeth are real! How they got there is, of course, probably wizards. $\endgroup$
    – JamieB
    Commented Jan 10, 2023 at 21:29
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Foolish Wyrmlings!

You can't eat a human tank raw. You have to cook it for a few seconds with your fire breath.
Then it gets soft and chewy, making it much easier to get at the juicy parts inside.

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  • $\begingroup$ Kinda facetious phrasing but actually not a bad answer, in a frame challenge sort of way. We just have to assume dragon breath is corrosive in some extraordinary (magical) sense. Perhaps it has the property of reducing density of any material by a fixed amount. Under that density, the material disintegrates. Over that density, the material survives but it turns steel into something with the density of styrofoam. $\endgroup$
    – JamieB
    Commented Jan 10, 2023 at 21:32
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What about biologically formed carbon nanotubes?

This webpage had this to say regarding their physical properties:

On a molecular level, CNTs are 100 times stronger than steel at one-sixth the weight and have a very large aspect ratio making them very useful as a mechanical property enhancing filler material. Carbon Nanotubes conduct heat and electricity similar to copper but without oxidative concerns provided that they are well dispersed.

Since the base element for the chemistry occurring in all known life is carbon, that part is at least somewhat plausible perhaps - however, I'm not au fait on whether it's anywhere within the realm of plausible for a biological mechanism to deposit carbon atoms into a matrix to produce nanotubes, but it could be perhaps, depending on how deep you want to explain the processes and so forth. The properties around heat might even lend themselves to explanations/applications concerning the fire breathing and so forth and/or reinforcement against it.

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I think this could work if you let me redesign the tank rather than the dragon.

Tanks are attacked using High-explosive anti-tank rounds. These use shaped charges to generate a sharp jet of Liquid Metal. This (or at least the shockwave generated by it) can pierce a foot of solid steel like a needle. The jet might be stopped by a bag of gravel. The gravel is non-uniform with voids which disrupts the jet into an unfocussed blast that the sub-armour can resist. Chobham armour has engineered voids that work in the same way. There is even explosive armour that actively disrupts the jet.

To resist HEAT rounds, or fantasy beam weapons, the tank may have an outer coating with a complicated system of lumps, oblique plates, explosive layers, and other stuff. This could be over a foot thick. It might be loosely attached so a section could be replaced if the tank was hit but survived. It might be torn off by conventional dragon teeth, because it was not designed to resist that.

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I'm a little late to the party, but I would like to offer my spin on "powerful teeth". Or something of the sort.


Worldeater.

That's the name they gave it. I thought it was appropriate until I saw that thing in action with my own two eyes, in front of me. Then I knew - it was nothing but a euphemism.

It's hard to explain what it is. Some say it's a machine, but don't believe them. That's no machine - you can see the glint in its eyes, the clever smile its magnificent jaws make when it finds prey, the small under-breath laugh it lets out after a successful hunt. No, sir - that thing has a soul, and it is one of the most evil things to walk the earth.

Or, "eat it", as it goes.

We didn't see it coming. Our radars went off earlier that evening, the fruit of masterful sabotage by the Final Future Brotherhood. Our systems blacked out. We thought it was just a power loss, but it was much bigger than that. It was coming for us, and it was hungry.

We had no time to evacuate. The Worldeater was upon us - a devious creature made out of cogs, pistons, plates, and bolts. A massive, walking, flying factory made into a weapon of mass destruction. It shouldn't be possible - the rational mind in me kept crying about the impossibility of that thing even existing, but there it was. Massive, glorious. A nightmare given machine form.

The thing had put itself on a shape that was a call to the devil itself: four massive legs, ending in claws the size of a truck each. The body was an impossibly complex, ever-twisting river of machinery that roared around a flaming core, encaged by plates upon plates of metal that kept just enough space between them for the interior to be visible and that horrid, noxious smoke to billow out from its flaming heart. The two giant wings spread out forever, holding upon its complex muscle-like systems of cables and bolts and an uncountable amount of engines, each one of them roaring on its own, in a chorus of unbridled potential. A giant tail dragged after it - an infinitely complex amalgamation of cogs and plates that moved as if it was alive, destroying whatever its massive claws missed.

And then, there was its mouth.

A gargantuan jaw that could destroy worlds, one bite at a time. That's how they told me it was, and it was true. So it was the thing: jaws so large they could swallow a man whole, without taking notice. Inside of it, there was death - not only from the crushing force its cogs and bolts and plates and cables could exert but also from the impossible hot flames that roared inside. The teeth were a chaotic mess of tools made for destruction - sharp fangs that could slice open steel, saws that buzzed horribly, ready to tear open even the most stubborn armor, macerators that could grab and pull whatever they touched and make it into nothing in a matter of moments. All of those constantly replaced - broken, used parts discarded inside its mouth-furnace to be recycled, while new ones were put in place, freshly from the beast's insides. It had no end. But there was something worse, even - the "fire breath" of the beast, the thing that made anything into its food - a row of nozzles, on each side, They spewed molten metal, white-hot, in a high-pressure jet that could slice anything they came in contact with - yet somehow they didn't seem to bother the creature's jaws, pooling on it as if it was the beast's own spit. There was nothing that could stop it - even a tank buckled beneath its power, its metal becoming red hot and then breaking, as the creature tore apart parts of it with each new voracious bite.

The Wolrdeater was limitless. Infinite. Beyond what we could even think possible. A machine given soul, freed from what we knew from physics, using its impossible engines and unfettered power to teach us a lesson.

Our downfall, made by our own hands.


They're made of "Tank". And "Person". And "Wall". And, anything else, really.

Don't make indestructible teeth - make destructive teeth. It's fine if they break, as long as they do enough damage to enable your target to be swallowed. Once that's done, just use whatever it eats up as material for its new "teeth".

Of course, that assumes that the dragon is a Lovecraftian god-machine made out of steel and rage-bent on destroying mankind, but still. That's just an implementation detail.

Remember: even water can be as powerful as a lightsaber if it is fast enough.

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