If you touch two CLEAN blocks of the same metal together in space, they weld!

[soothsayer]

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Sophia Gad-Nasr
@Astropartigirl
If you touch two CLEAN blocks of the same metal together in space, they weld!
Atoms in solid metals move a bit. Touch two clean surfaces together, and the atoms can't tell they're in different blocks so they become one group of atoms, ie ONE SOLID.


Sophia Gad-Nasr
@Astropartigirl
·
Jul 10, 2020
Replying to @Astropartigirl
The reason it doesn't happen on Earth when you put two of the same metals together is because of oxygen, which causes metal to rust. That oxide layer sits the two metal surfaces, so atoms in each block see a layer of different atoms, and know that's their "limit" for movement.

Sophia Gad-Nasr
@Astropartigirl
If you're wondering if this has affected space missions, it has! The Galileo space probe sent to Jupiter couldn't deploy its high gain antenna on the way to Jupiter because the metal rods that were to open up the "umbrella" got cold welded together!

[RKP5637]

1. Wow, Incredibly interesting!!! It certainly makes sense. n/t

[tblue37]

2. Fascinating! K&R and thanks. nt

[secondwind]

3. This is SOOO cool!!

I LOVE SCIENCE!!!!!!!!!!!!!!

Thanks for posting

[Bayard]

4. Interesting

There should be some practical use for this. I'm guessing they let loose again back in an oxygen atmosphere.

[soothsayer]

8. I believe they stay bonded

[bullimiami]

11. stunningly you could assemble parts as a single component with no welding and no machining.

premake all the parts. assemble in space. maybe a tad expensive just now.

[Jazz Jon]

5. Chemistry

The metal atoms in a solid block make chemical bonds with each other, which hold them together in a block. On earth two separate blocks would be spaced apart by gas (atomosphere) or oxidized metal in between. This spaces the blocks too far apart for the bonds to form. The pure metals don't bond with intervening materials either because the chemical properties are wrong (the wrong number of electrons in the atoms outer shells). Replace the interfering materials with emptiness ( outer space), and the metal atoms will do what they do... bond.

[central scrutinizer]

12. Wouldn't it also work in a vacuum chamber

Here on Earth? Maybe an artificial vacuum chamber still has enough molecules of gases to interfere with the welding?

[SCantiGOP]

7. So glad Science is legal again

It sure beats “Many people are saying...”

[brush]

9. Well that changes things.

[NNadir]

10. This is the Kirchendall effect, which has been something of a joke in my family.

I made fun of my son when he was an undergraduate materials science student. when I asked him if he knew about it, and he didn't, whereupon I made fun of him for not being as smart as his father. (In reality, he's way, way, way smarter than I am.) It was before he had a course in metallurgy.

His graduate work is in a metallurgical lab, so he's getting revenge on me.

It's not a new discovery. It was discovered in 1947.