Tiny crack in steel seen through an electron microscope


Originally published at: http://boingboing.net/2017/03/10/tiny-crack-in-steel-seen-throu.html



Great, now i want to to go camping and raft the Grand Crackion.


Colors photoshopped too, I think since the electrons (electron microscope) don’t have any idea what the color of the item they’re hitting are…


I expected dick-butt. Anyone else expect dick-butt?


That’s crackalackin.


Correct. (Cringing at “have[ing] any idea”, though…)

Pedant’s note: it’s not an Electron Microscope (EM), but a Scanning Electron Microscope (SEM) picture.


So I guess HBO cancelled Vinyl.


If I looked out of a plane window and saw rust around the rivets I would be terrified. Because alumin(i)um doesn’t rust.

Pointless fact: in the early days of machinery not much was understood about cracks and their propagation. The result was that the safety factor for the connecting rod of a high pressure steam engine in the 19th century was about 18 - it was made 18 times bigger and heavier than theory suggested. However, the DC10 ran into trouble because it was designed with a safety factor of only 1.4 on a number of parts. Manufacturing and inspection technology were not quite up to it, and it didn’t help that mechanics were removing the engines using a forklift rather than the special fixtures.

So while nowadays pictures of cracks in steel are interesting, until recent years they were the things that prevented us having the nice things we have now - lightweight engines, safe aircraft, nuclear reactors and (usually) washing machines, multi-megawatt wind turbines and ridiculously fast motorcycles.

That is being very pedantic since SEMs are a subset of EMs.


“There’s probably one of these on the plane you just boarded, lurking somewhere the hard-pressed engineers and inspectors might have missed.”

Coincidentally, I met a man on Wednesday who claimed to be a nuclear-grade welder. It was halfway interesting to hear what it takes to do that.
I say halfway, because the testing required for such a job must be really hard, but listening to his pompous attitude was equally hard.


True. Apologies.
Happens because of my experience: at every University I studied or taught, everybody referred to the SEM as SEM (or REM, in German), and to the TEM simply as EM.


At least for the cases where you are using electrons because the details you want to observe are too small to resolve with the wavelength limitations of light; I’m not sure that you can really say that the items you are hitting have colors; except in the very limited sense that macroscale collections of that particular material and geometry have a color.


Colours are purely a construct of the way the human eye works, so you can be quite sure.


No apologies needed, it was just an observation. But you’re right, informal scientific terminology is often rather…unscientific. Truth is I’ve never been in a position where a TEM would be the slightest use, so in talking to a lay person I would just say “electron microscope” and mean SEM.

edit - on the other hand I can be extremely pedantic. And wrong.


I could only hear that description read in the voice of Raymond Edward Johnson.


Not to be pedantic, but aluminum does oxidize in its own way, if you see white surface power or buildup that’s aluminum “rust”.


Of course, and if you saw oxidation building up around a rivet on a plane wing, that’s time to worry a lot because it normally implies that the rivet and the skin have an electrochemical potential - they are not the same metal. But for that to happen the most likely scenario would be a steel or bronze rivet in an aluminium panel, which would be bad news indeed*. Not so bad if there’s only one in a bodged repair.
“Rust”, however, almost invariably refers to oxidation of a ferrous material. For aluminium or tin, it’s oxidation; for brass and bronze the usual term is corrosion.

*because it implies there might be other, more serious, bad maintenance. Enkita, avoiding Third World airlines since the 1980s.


Do you have any idea how long it took the Colorado River to carve that crack in that tiny bit of steel?


“Canyon or crack?”

Nature is lousy with fractals.


I would have faked it and done this: