High Density Reactive Materials

[TeufelIV]

An interesting article that Ifound the other day, that refers to High Density Reactive Materials

BBC Article: U.S. Military develops "Bigger Bang" Explosive Material

Wikipedia link

Wired.com Article

I know I have read about this before in places on the net but I can't seem to find the articles that referred to it.

It is made of a polymer/metal compound and apparently relies on impact energy to set off the material. With that in mind how stable would this material be?

Is there any other substance or material that has this behaviour?

What are some of the other possible uses then munitions casings and fillers?

Also if any of you stumble across other related

[Parricidium]

Is there any other substance or material that has this behaviour?

This reminds me of a similar material I read about a few years ago. Essentially, it is a flexible material which reacts quickly to high kinetic energy and hardens upon impact, such as with a bullet (why it was being designed in the first place - for flexible but protective bulletproof armor).

[TeufelIV]

Sounds similar to non-newtonian fluids well sort of.

The impression I get from this article is that the substance gets a big jolt of kinetic energy it triggers some sort of chemical reaction like with explosives being detonated.

[Sea Skimmer]

It is made of a polymer/metal compound and apparently relies on impact energy to set off the material. With that in mind how stable would this material be?

Way more stable then conventional stuff. Many reactive material compounds can essentially only be combusted by a high speed impact, others only be extremely high thermal or electrical impulses. All of them are more stable then the current state of the art insensitive munitions, and the standards for IM are already very impressive. The hard part is making the stuff ever explode in the first place as by definition reactive materials are ones which are not traditionally viewed as explosive hazards

Is there any other substance or material that has this behaviour?

Well dozens of different compounds like this are being tested and have been at least since the early 2000s, building on research decades old. It appears the Tactical Tomahawk is already using a warhead with a combusting titanium case and so are a number of demolition charges intended for attacking concrete and old munitions. Pretty much all the current RM warheads are all based on some formula of combusting metal and a lot of metals can be made to do it under the right conditions. The metal content is why they can be much more powerful then conventional explosives. They are denser in the first place. You can use that combustion heat as the weapon itself, or you can reformulate the warhead to apply that heat to other materials which make a great deal of gas to give yourself a more intensive blast. Or both. Or a lot of other things, which is why it’s a wide field of research.

What are some of the other possible uses then munitions casings and fillers?

Anywhere you need a sudden high intensity heat, they are potentially useful for bonding materials together and new forms of explosive welding. I wouldn't be surprised if other small scale uses are found.

[TeufelIV]

I was wondering about possible use in explosive welding.

I have seen stuff for bullets and shells with the material but was unsure of their potential. Another use I saw widely suggested using them for sub-munitions because they are supposedly harmless if they do not go off. One of the articles said they would build a fire and incinerate the remains of the munitions safely.

Could you possibly use this enhance or make a new class of incendiary weapons?

Ok now that I am home and not at work I had no trouble finding some more articles.

A whole string of wired articles. After I have gone through and reread them I remember more about this material now. There is a bunch of other links I was able to find additional stuff. Most of the stuff I found originally was through pop. mech and wired. Globalsecurity.org probably has an article as well.

Wired Article 1
Wired Article 2
Wired Article 3
Wired Article 4
Wired Article 5
Wired Article 6

Pop. Mechanics Article
Advanced Energetic Materials from the National Academic press
Army Research Lab Characterization of the Combustion Behavior of Aluminum-Nickel Based Reactive Materials
Patent stuff

[Sea Skimmer]

I was wondering about possible use in explosive welding.

I have seen stuff for bullets and shells with the material but was unsure of their potential. Another use I saw widely suggested using them for sub-munitions because they are supposedly harmless if they do not go off.

Basically yeah. They are like submunition in that they combust on impact with hard targets, and yet like a fragment in that it is basically a piece of metal. Because combustion from an impact requires high velocity, you also have a predictable radius of expanded damage; though at lower speeds the fragment will still act as a fragment and shred stuff. This effect however can be controlled by making the fragments very small, so they quickly loose velocity in the air, leading to a relatively focused damage radius.

Weapons using focused fragmentation like this, minus the burning metal, are already becoming common under the heading of Dense Inert Metal Explosives or DIME. Basically they make micro shrapnel out of tungsten, and mix it directly into the explosives, then pour the mixture into a thin cased bomb. The result is the micro shrapnel is massively lethal at close range (death of ten thousand cuts) but the very lightweight particles quickly loose velocity and cease to be lethal. The only downside is, people caught in the narrow window between lethal effects and the shrapnel becoming harmless end up with a body filled with hundreds of tiny particles that doctors will never be able to cut out. This may lead to cancer or other long term problems; but of course with a traditional bomb you might have taken an arm a head off so does it really matter? The US Small Diameter Bomb (which is not thin cased, but it seems the case breaks into only a few pieces) and some specialist small missile and bomb warheads use DIME in US and Israeli service. Other powers may have it by now as well, though people on earth still don't give a damn about collateral damage. They'll be jumping all over reactive materials soon enough; though said warheads can be very difficult and expensive to produce. In some cases the RM compound actually has to be sprayed onto a warhead mold or baseplate as a plasma.

Could you possibly use this enhance or make a new class of incendiary weapons?

Essentially what you are doing is making everything incendiary, without being purely incendiary which is not that useful of a class of weapon anymore. Traditionally you need dedicated incendiarys; either complete bombs or parts of bombs, because most stuff wont burn from a short sudden heat impulse such as the one produced by normal explosions. You needed sustained heat such as that from termite, magnesium, napalm or zirconium.

With reactive materials, the heat is still released in a flash, but it’s much more intensive then the heat you’d get from some normal explosives going off, so you can now instantly set fire to a lot of stuff that would previously only have been scorched. Making reactive materials burn for a protracted period of time is not, as far as I can tell, feasible. But that’s just not a very necessary thing at the moment anyway.

[Sky Captain]

Could this new material be used as more effective solid rocket fuel?

[Sea Skimmer]

Yes and its being worked on. Keeping in mind that many rocket propellants already have around 15% metal content, normally aluminum, replacing some of this metal with reactive materials can add significant amounts of energy by making the exhaust hotter and thus higher pressure. You wouldn’t want a very high proportion of reactive materials in a rocket fuel because they mostly produce heat, not gas, and heat alone accomplishes nothing for a rocket. This field of research doesn't seem to have gone as far as the explosives research because reactive materials are expensive, and while that may be worth it for something like a Stinger missile fuel wise, its probably not going to turn into an advantage for say, space launches when you are talking about burning up hundreds of tons. But I could be wrong on that.

[TeufelIV]

Interesting. So it has a much more intense thermal pulse then standard HE weapon.

So the gist I am getting is that this material is more potent then even HE bombs with additives like powdered aluminum or other explosive accelerants/ehancers. This might make an interesting assault or HE grenade filler.

This sounds like it might have some interesting civil demolitions uses as well as the obvious military ones.

Well sounds like this yet another substance to keep track of in the years to come.