Metals Fuse Together in Space

https://www.spacecentre.nz/resources/facts/physics/metals-fuse.html

by redbell • 3 years ago

184 74 3 years ago

Lerc• 3 years ago

I have often wondered if you could chop a nickle-iron asteroid into 1 meter cubes whether you could construct a space-station Minecraft style. I would probably have some tapered+oxidized surfaces so you could align things nicely before the fusing happens, but it sounds like a fun way to make huge structures.

Chopping up the asteroid left as an exercise for the reader.

jamiek884• 3 years ago

Well if you look at the accuracy and precision cutting and tessellation of some of the stone work the ancients did, starting with the Sumerians in the very first cities it would be fitting if our first cities in space were made by similar techniques but this time, with lasers!

psd1• 3 years ago

Easy! Start by chopping the asteroid into tessellating hendecahedra, then use one of the faces of each solid as a reference surface to project a cube of known size.

lstodd2• 3 years ago

Nonono, no such abomination please.

Let's do it with rhombododecahedra.

mberning• 3 years ago

If you are interested in this type of thing look up gauge blocks. And wringing gauge blocks.

anonymousiam4• 3 years ago

The article says "it has happened" and cites a footnote mentioning the Galileo antenna deployment. I was part of the team that built the Galileo Jupiter Atmospheric Probe and followed most aspects of the whole mission closely, but I have never before heard of this being the cause of the antenna deployment problem. I just read the cited paper (from 1994) and it does seem to be conclusive. If websites like HN had been operating in 1994, this news probably would have reached me almost three decades ago.

https://en.wikipedia.org/wiki/Galileo_(spacecraft)#Galileo_e...

silentsea902• 3 years ago

Wow! You were part of NASA in the 80s? So cool.

anonymousiam4• 3 years ago

Not part of NASA -- I worked for Hughes Aircraft Space & Communications Group, on contract with JPL to produce the probe. The contract was awarded to Hughes because of their previous work on the Venus probes: https://en.wikipedia.org/wiki/Pioneer_Venus_Multiprobe#Space...

Those probes were created and launched a few years before I joined the company. I was a new employee when Hughes was producing the Galileo probe and my role was minor.

I spent 35 years with the company -- the last half with Boeing, who acquired it from GM around the year 2001. For the most part, it was my dream job and I really enjoyed working with the best and brightest people.

Terr_3• 3 years ago

That reminds me of a fictional space-engineer:

"Some of them are visibly fused. Some idiot must have welded them.”
“Welded, yes. But not by some idiot. By the sun.”
“Leo, it doesn’t get that hot—”
“Not directly. What you’re seeing is spontaneous vacuum diffusion welding. Metal molecules are evaporating off the surfaces of the pieces in the vacuum. Slowly, to be sure, but it’s a measurable phenomenon. On the clamped areas they migrate into their neighboring surfaces and eventually achieve quite a nice bond. A little faster for the hot pieces on the sun side, a little slower for the cold pieces in the shade—but I’ll bet some of those clamps have been in place for twenty years.”

-- Falling Free (1988) by Lois McMaster Bujold

jamiek884• 3 years ago

You know, I’m a hyper voracious reader of sci fi and I’ve never read any Bujold.

I’m down to correct that strange oversight, do you recommend that novel as a decent starting point? If that quote is representative it seems right up my street!

loeg• 3 years ago

If you want the author's recommendation on reading order, http://www.dendarii.com/reading_order.html . The whole series is pretty good.

robto• 3 years ago

Falling Free is a great place to start, as it has a stand-alone plot and introduces the setting very well. If you like it then I'd also recommend the Vorkosigan saga.

simpaticoder• 3 years ago

Lois McMaster Bujold is one of those authors that never got as popular as they deserved. She does have a niche following, though. The Vorkosigan saga is very solid space opera with, unusually for SF, innovative and sensitive character work.

foobiekr• 3 years ago

It appears "Falling Free" is currently part of Audible Plus, if you are an Audible user and audiobook kind of person.

Brian_K_White5• 3 years ago

That quote is a bit outlier in my opinion. She doesn't do all that much technolecture like that.

The series is pretty full of sci-fi ideas and real application of them and exploration of their consequences though. I don't mean to imply it's sf in name only but really fantasy with search & replace.

It's a bit hard to pick a single first book to suggest, because while most of the series centers around a particular character Miles Vorkosigan, the first book I would suggest takes place a bit earlier and centers around his parents.

And then yet another difficulty is that book is a sequel to another, and it's hard to recommend not reading those two in order, even if I think the 2nd is the real heart and soul and spirtitual kicking-off point of the whole thing. And this is already including the fact that I'm already not being a slave to chronology, already skipping over some other prequels that really don't need to be read in order at all. They are hundreds of years earlier and do not need to be read in any particular order. It's just these two where, the real choice gem and spritual kicking-off-point of the whole thing in my opinion happens to be a close sequel to another that, IF you read the 2nd and liked it, then it it hurts the 1st a little to have to then read that after.

So I want to say Barrayar, but it is such a close sequel to Shards of Honor, that it should really be Shards of Honor. And really, it's not like Shards is weak. It's great. Very in-line with the rest in tone and quality. It is pretty much as good as any other as a litmus test for if you will like the rest.

The progression goes like, Shards is great and is I think a good place to start reading the whole thing, but Barrayar that comes next is even better, and BOTH of those still aren't even centered around Miles yet, who is the center of most of the rest. So it starts off great, gets better, and then better again, and yet I don't really think it would be great to start with one of the Miles books, even if you are testing to see if you maybe don't even care for the style or the series in general. Test a whole series without spending any time with that series main character???? Yeah. Well that's why I say a bit hard to pick a suggestion ;)

I guess I can say it this way: It's definitely safe that if you did like Shards that you then somehow won't like all the Miles books. The trasition to to following Miles around won't be like "Wtf is this crap? My good series went bad!" And it's pretty safe that if you did not like Shards, that the others aren't different enough that you would love them and miss out by a false negative impression from Shards.

Shards of Honor.

Terr_3• 3 years ago

The question isn't quite as hard as with Terry Pratchett novels (yes, I do place Bujold in that tier) and I think the major choices boil down to:

1. Cordelias' Honor: Unusually, this is not about the character who will star in the next umpteen novels, but it does a lot of world-building and introduces some important characters who will be pervasive supporting cast later. (It's an omnibus that merges what was originally published separately: Shards of Honor, Aftermath, Barrayar.)

2. The Warrior's Apprentice: The first of the books focusing on the main protagonist of the rest of the series, however if you value knowing the world-building, backstories, and references to earlier books, then this would be a weaker start.

3. Falling Free: A stand-alone novel 200 years earlier in the main universe, which can be good or bad depending on your appetite.

Honorable mention: The Curse of Chalion if you prefer fantasy. [0]

_________

[0] There's also The Sharing Knife series which is... I dunno, fantasy of the hinted-post-apocalyptic variety? Somehow I was never drawn into those, in my dim memory they were disappointing.*

willis936• 3 years ago

It also reminded me of gundanium. I wonder if cold welding inspired it.

https://gundam.fandom.com/wiki/Gundanium_Alloy

swayvil• 3 years ago

Hey physics guys.

So atoms in metal share electrons.

I hear that's like a plasma (floaty electrons, conductive)

So is metal a solid plasma?

Rury2• 3 years ago

Plasmas, and the states of matter, are more of a convenient categorical heuristic than actual things. We categorize matter as so, so we can conveniently convey information about a material's conditional properties, but any material can be a solid/liquid/gas/plasma under the right conditions...

But a solid is not a plasma, as by definition a plasma also has properties of a gas. So a solid metal is not a plasma even if they share some properties. In other words, a plasma is not a solid, and so "solid plasma" is a kind of an oxymoron.

To really drive the point... any metal can be in either the solid or plasma states, so thinking of them as "solid plasmas" isn't really correct.

uoaei2• 3 years ago

"Solid chunk with electrons free to conduct through it" and "gaseous chunk with electrons free to conduct through it" are pretty similar. Sure it's technically an oxymoron but really rather close to accurate. Maybe pedants would be happier with "solidified plasma".

jamiek884• 3 years ago

Short answer: no.

They have similarities such as you mentioned but only at relatively low energies.

There are several sorts of plasmas. An ionized gas is a sort of plasma, also called thin plasma.

Thin plasmas, while physically different from a metal, share a surprisingly large number of properties with it:

They both have two separate charge carriers, cations and electrons. On both, the cations have a negligible contribution to current and the electrons form a gas. They have similar dispersion relations (leading to similar "local" Ohm's law in both). It's because cations don't contribute much that they seem similar, in spite of one being a gas and the other a solid.

You may enjoy this physics stack overflow thread for an expanded answer:

https://physics.stackexchange.com/questions/717274/how-is-a-...

ThrowawayTestr• 3 years ago

Cold welding is the kind of thing that makes sense when you think about it but is still crazy that it actually happens.

quickthrower2• 3 years ago

Hmm: Does frozen water do the same in space?

Why doesn’t it do it on earth? Is it the air in the way?

mcswell• 3 years ago

Dunno, but I've heard that tongues can weld themselves to icicles on Earth.

20after4• 3 years ago

ice cubes stick to other ice cubes, I would assume it's because of melting and refreezing but I can see one reason why cold welding might not happen: Ice is dihydrogen oxide, so that oxygen atom might be a problem for cold welding.

westurner• 3 years ago

Cold welding: https://en.wikipedia.org/wiki/Cold_welding

"Autonomous healing of fatigue cracks via cold welding" (2023) https://www.nature.com/articles/s41586-023-06223-0 :

[...] However, unexpectedly, cracks were also observed to heal by a process that can be described as crack flank cold welding induced by a combination of local stress state and grain boundary migration. The premise that fatigue cracks can autonomously heal in metals through local interaction with microstructural features challenges the most fundamental theories on how engineers design and evaluate fatigue life in structural materials. We discuss the implications for fatigue in a variety of service environments.

https://www.agriculture.com/machinery/maintenance--repair/im... :

Cold weld is a common – although incorrect – term used to describe the process of using filled epoxy glue to repair broken metal machinery components. The product is a combination of a plastic resin compound and finely powdered steel. A catalyst, or hardener, is added to this mixture to cause a chemical reaction, which hardens the putty into a solid mass

Cold spraying: https://en.wikipedia.org/wiki/Cold_spraying

georgeburdell• 3 years ago

I worked with vacuum systems in grad school and this sometimes happened if we scraped one metal part a bit too hard on another when positioning a sample inside a characterization chamber. Cue having to vent the system to extricate the sample manually, followed by at least a couple of days of effort to get the chamber back to ultra high vacuum, such as wrapping the chamber with heating pads to force adsorbed water to leave quicker.

badcppdev• 3 years ago

I know it's not trivial but do organisation working with vacuum chambers ever set it up so that the atmosphere inside a pressure vessel is kept full of dehydrated oxygen/nitrogen air at positive pressure during maintenance activities?

I know they make sure that all the workers suit up to prevent oil from skin ruining any chance at a high vacuum.

V1ndaar• 3 years ago

Sure, it's very common to flush a system with dry nitrogen for that reason. But of course if you have to fully open a part of the system you're usually out of luck (also you usually don't have valves at every intersection etc., so some part may still be exposed to the atmosphere even if part is "kept dry").

lettergram• 3 years ago

Wonder if this is what verda space can really accelerate at?

lucubratory• 3 years ago

There are probably manufacturing benefits of vacuum welding for some niche use cases, but it's a thing that happens with vacuum, not microgravity. Because it's cheaper to build a volume under high vacuum here on Earth than it is to send equipment up to space, that means it can't be an economic reason to go to space. It's more that it's one of those "If you're already in space, this probably has uses" things, rather than a "This is going to return on the investment of going to space" thing like Avatar's unobtainium or Andy Weir's special fiber optics.

xwdv• 3 years ago

So essentially if you break a metal rod in space you can just stick the broken ends back together and it fuses up again.

analog31• 3 years ago

If it fits perfectly. Unfortunately, the breaking probably deforms the two ends.

There's a process in optics called "optical contacting" where you take two super-flat surfaces, push them together, and they stick. This is used in some specialized components where there can be no gap or optical adhesive at the interface. The pieces really do stick together. With optics, you don't have to worry about the materials oxidizing at the surface.

Also if you break a rod in space, you'd better be holding on to both pieces. ;-)

drunkonvinyl• 3 years ago

I’ve done this with two hard drive platters. Never knew it had a name. Cool.

kstrauser• 3 years ago

Someone explained cold welding to me this way:

"So you have 2 pieces of metal pressed together. How does an atom know which piece it belongs to?"

Oh. I know there's more to it than that, but that unblocked my understanding of it.

thsksbd3• 3 years ago

By the massive free volume between them. Even if you clamp the two metals together tightly, unless the surfaces are atomically smooth you'll get void spaces that are large kinetic barriers.

Even if you are dealing with atomically smooth surfaces, you'll get a grain boundary which is still a kinetic barrier, and a large grain boundary too.

That being said, your friend's point is still fundamentally valid - why wouldn't an atom on occasion cross the boundary and switch sides?

Brian_K_White5• 3 years ago

And yet, vacuum-welding is a long known actual thing, and even without vacuum right in ordinary human environment, by good, non-trivial, but not magical surface prep. But it's probably more than just proximity. In vacuum there is probably also evaporation and a form of electrolosis.

TheSpiceIsLife2• 3 years ago

No that huge a void.

Optically flat polished metals, such as guage blocks, will form a few metallic bonds when pressed together.

ortusdux2• 3 years ago

Surprisingly, explosive welding is considered to be a cold welding process. Explosives are used to overcome the limitations you describe.

vGPU• 3 years ago

In atmosphere, most common metals will have a layer of oxide or contamination on the surface.

This process is also known as diffusion bonding.

ortusdux2• 3 years ago

That is similar to how Feynman explained it in his Lectures:

“The reason for this unexpected behavior is that when the atoms in contact are all of the same kind, there is no way for the atoms to ‘know’ that they are in different pieces of copper. When there are other atoms, in the oxides and greases and more complicated thin surface layers of contaminants in between, the atoms ‘know’ when they are not on the same part.”

garof2• 3 years ago

It also makes me think of sticking two clean pieces of (optical) glass together without glue: https://en.wikipedia.org/wiki/Optical_contact_bonding

TheSpiceIsLife2• 3 years ago

This would be the same phenomenon that causes guage blocks to stick together, I presume?

garof2• 3 years ago

Not sure. Contact bonding can be strong enough to pull chunks out of one or the other of the glass pieces when you try to separate them. I've not personally seen this happen, only the results.

the__alchemist• 3 years ago

Is this recently posted thread about diamonds self-healing related?: https://news.ycombinator.com/item?id=37785458

mjan22640• 3 years ago

The molecules of a solid exert ~10x attractive force compared to molecules of a gas. In the Earths atmosphere every solid surface has a layer of gas molecules stuck to it, that prevents cold welding from happening.

thsksbd3• 3 years ago

Gauge blocks stick together quite forcibly in a dirty machine shop, never mind outer space.

And how often have my glassware stuck together after I stacked them up?

uoaei2• 3 years ago

Those are both examples of vacuum suction, not welding.

BenjiWiebe2• 3 years ago

I don't think either of those is an example of vacuum suction. Gauge blocks are thought to work in a small part by vacuum, but mainly by other means. Glassware sticks together because of thermal expansion/contraction, combined with being quite smooth and very hard and inflexible.

BananaaRepublik• 3 years ago

In school, they used to teach us about the atomic structure of metals being an orderly lattice. Being an orderly lattice, if two pieces of metals were in contact with each other, there wouldn't be any indication of where one piece ended and where the other began. Is this why it fuses in space?

jgamman• 3 years ago

Awesome - this is the website of the Te Awamutu space centre. "The Space Centre is a privately-funded project run by Dave Owen (Space Dave) and his family." Te Awamutu is a town with ~13,000 people. Live your best life Dave! kia kaha ;-)

exitb• 3 years ago

It's always interesting how living on Earth wraps our perception and makes it somewhat difficult to understand how things really are. Like Newton's First Law, which is in a way completely obvious, but not very intuitive in an environment where all seemingly "undisturbed" moving things eventually stop.

The real news is that metals don't fuse together on Earth.

cuSetanta• 3 years ago

Cold welding is a concern that we have to account for during spacecraft assembly, sometimes you really really don't want two pieces of metal to weld themselves together after all.

To prevent it we wither ensure a reasonable gap (if possible). Which has serious impacts on heat transfer. Or use dissimilar materials to prevent it from happening.

TheRealHB• 3 years ago

Space welding!

joelthelion• 3 years ago

Could this have real-world applications on earth? Getting a good vacuum and cleaning the parts doesn't seem terribly hard.

How long does the process take?

inkcapmushroom• 3 years ago

I could be wrong but usually melting and molding the metal is an easier way to get a specific shape on Earth. Don't see why you couldn't just do that if you wanted a combination of some shapes.

I'm wondering if there's an application as a self-destruction mechanism on a lock or something like that. There's still far easier methods.

Metals Fuse Together in Space

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