Laser-powered bullets reveal surprising metal hardness

Conventional thinking suggests that metals soften as they warm. But this isn't always true, as researchers have succeeded in demonstrating that under extreme conditions, metals actually get harder as they get hotter.

By shooting metal targets with tiny, laser-powered projectiles, this team was able to create incredibly high strain rates. Under these conditions a property called drag strengthening comes into play giving rise to metals that behave in counterintuitive ways, and could inform high speed manufacture or aerospace engineering.

[lbgstzockt]

"optically-driven microballistics" is my favorite term of the day.

[kinfongyeung]

did not expect the heavy metal music from nature

[vaibhavkodiyan]

Wow, this video blew my mind! I always thought metals just got softer with heat, but the whole idea of them getting harder under certain conditions is a game-changer. The way they used lasers to shoot tiny particles at metals and then caught it all on camera is just next-level cool. It's like a glimpse into the future of materials science. Kudos to the team behind this - super fascinating stuff!

[jackmclane]

We're talking about toughness and not strength here.
Metals are more brittle (less tough) under shock loads, especially when it is cold. That is WELL known for ages.

[akituln]

Could it be that the higher temps increased the elastisity of the metals?

[SteveWard]

Why do the crater graphs not support the claim? Looks like higher temp impact left a smaller crater. Also, someone would have noticed if copper really got stronger at higher temps.

[jimk]

Is this why a copper jet from an rpg works so well?

[GrilledCheeseSandwich]

You mentioned hypervelocity (3000m/s) but the study didn't even reach 10% of that:

>The velocities targeted in this study (below 250 m s−1 for copper and titanium and below 150 m s−1 for gold) are all slightly low compared with conventional high-rate test-ing;

[sbreheny]

How does this jive with adiabatic shear? Very high shear strain rates have been shown to cause extreme local heating which in turn softens the metal locally and causes more shear strain than otherwise expected based on the bulk temperature of the metal.

[Kris-fdxs]

Running around in cherry red ar500 plates makes you invincible 💥

[stefansauvageonwhat-a-twis]

Cool, sad I cant find more about drag strengthening online easily

[RickCarroll-jn]

D3O mix with powdered hemp coated with Teflon won't stop it ever

[ToeCutter]

well... lets see now... the reason RPG's punch through most tank armor is because it's MOLTEN COPPER propelled at a rate of ~7 to 8 miles per second(that's AFTER it hits it's target and the shape charge detonates). it acts like an uncompressible hydraulic fluid so of course it's going to be "harder". it's like the same effect of dropping large objects in water, the higher the speed the shallower it penetrates(at least up to a certain size like a meteorite or asteroid that has sufficient enough mass to overcome the surface tension).

[engineeringdisillusion]

This is well known and exploited both in aerospace and military applications.

[MyNordlys]

Maybe also this works on shaped charges with copper, increasing their penetration ability ?

[ARVash]

This is the first time I've heard phonons be used in a practical context.

[mrpicky]

doubtful setup. as thermal energy is kinetic actually . what they tested here is how much of thermal energy in shield transfers to the bullet. so they might have wrong conclusions

[tymz-r-achangin]

Cool thinking to add heavy metal music to a hard metal video

[ModelGenerativeANdroid]

2:55 this proves that ancient Egypt makes the pyramids with copper chisel & copper saw.

[SkepTank]

so, basically, when a metal is hot enough it acts like a non-newtonian fluid? hmm