Metal foam obliterates bullets

This doesn&#x27;t have much in the way of interesting details, you need to go to the paper for that.<p>The armour is a composite sandwich, with boron carbide on the front face (a hard ceramic), followed by the metal foam, and either aluminium or kevlar on the rear face.<p>The boron carbide layer blunts the bullet and distributes the compressive stress over a large area of the metal foam. The metal foam is made of 2mm-diameter hollow steel spheres in a stainless steel matrix (created using powder metallurgy). The metal foam deforms plastically under the compressive stress, absorbing the kinetic energy of the projectile (i.e. the spheres get crushed). The backplate provides tensile strength and stops the foam from tearing apart due to residual tensile stresses.

I did modelling work for a group researching metal foams in my past academic life. Very interesting stuff with a lot of applications if the manufacturing processes can be nailed down.<p>Our funding was a mixture of European Space Agency and a car conglomerate: light armour for space vehicles and crumple zones &#x2F; reinforcement respectively (less acceptable to research military applications in EU in my experience).

Would this be effective against micrometeoroids and orbital debris?

The part about shielding radiation sounds dubious to me. I thought shielding from radiation was mostly about mass. How is that foam supposed to shield better than cast metal of the same weight? Maybe the &quot;foam&quot; deteriorates less?

&gt; Last year, with support from the Department of Energy&#x27;s Office of Nuclear Energy, Rabiei showed that CMFs are very effective at shielding X-rays, gamma rays and neutron radiation.<p>Designers of spacecraft and lunar&#x2F;Mars bases are likely pretty happy about this development.

Neat, though of course this raises the question: what would it take to engineer a foam-piercing bullet?

<a href="http:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=wfFcs25KmMc" rel="nofollow">http:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=wfFcs25KmMc</a> more about the inventor.

I found the post-impact part of the video interesting. The article says &quot;turn an armor-piercing bullet into dust on impact&quot;. But in the video, it looks like it turns it into a lot of metal particles &#x2F; shrapnel. As a body armor it looks like it could be increase the danger to those around a person getting hit.

Are there any potential downsides to this stuff? It seems too good to be true.

This reminds me of an old Mythbusters experiment where they showed that covering a wall in the same stuff people put in the bottom of their trucks can protect the wall from explosions.

Looking at the ammo channel for I think the same ammo the results don&#x27;t seem that remarkable. The foam article quotes &quot;less than an inch&quot;, the ammo test article has about 1 inch for mild steel and 0.319 inches for AR500 plate<p><a href="http:&#x2F;&#x2F;www.ammochannel.com&#x2F;30-06-30-cal-m2-ap-armor-piercing&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.ammochannel.com&#x2F;30-06-30-cal-m2-ap-armor-piercing...</a>

What if you shoot twice at the same spot?

&quot;showed that CMFs are very effective at shielding... gamma rays...&quot;<p>Really? That would be quite an achievement.

Sweet - when can I buy level IV plates made out of this stuff?

I read about it as a child. On earth, molten metals readily lose gas by the force of gravity, but in space, you can easily make metal foams that will be very strong and light. Sounds like a good material for spacecrafts.<p>Also, how about glass foam? I imagine you can blow large and cheap hulls from foamed molten glass.

And a big ass gun &#x2F;