121–130 of 162 posts
The essential quality of the metal is its being rigid with the ability to deform without fracturing, so talking about its strength is useless. There are tons of things that are stronger than steel already. Still, they don't also have the property of deforming without destruction or, on the opposite, holding its form rigidly while maintaining its strength.
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> a couple of concerns - Can it be recycled? Right. We have enough issues with plastic waste, without it having extra-ordinary strength.
Also steel is 100% recyclable. If I recall correctly, most steel used today is recycled.
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It is quite certain that a 2-dimensional polymer cannot be recycled like metal, glass or a thermoplastic material, i.e. by remelting or by plastic deformation at high temperatures, because a 2-dimensional polymer cannot be deformed without breaking covalent bonds and it cannot flow in a liquid state. So this new material might behave like the existing cured polymeric resins, e.g. epoxy resins, which form a 3-dimensio…
You seem to be assuming that the 2D polymers extend indefinitely. If instead their growth is limited such that the molecules tile, overlap, and layer, they may be more amenable to manipulation such as thermoforming, thermosetting, etc.
The advantages that they claim over conventional polymers, e.g. inpermeability and high tensile strength, are conditioned by such large extents. If the 2D sheets would be small enough to slide over each other and insert between other sheet fragments, so that plastic deformation would be possible, then they would also lose any advantages over traditional polymers.
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And is that strength enough to put vacuum airships back on the menu?
I'm intrigued. What's a vacuum airship?
Like a blimp but with a rigid balloon filled (ha ha) with vacuum instead of a light gas.
The article is saying it's a polymer so I'm guessing it doesn't have the right rigidity, ie, the stronger than steel bit must be with respect to a different strength measure
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I’ve often heard that spider silk is stronger per kg (or is it per m^3?) than steel. Are they talking about pulling, compressing, sliding, or all of the above?
Plenty of things are stronger than steel on a per pound basis. For instance, many aluminum alloys have about 60-80% the tensile strength of steel, but only 1/3rd the weight.
Just a heads up - strength is not a single metric. There is tensile (pulling), compression, and shear (sliding) strength. There's also Young's modulus (how much something stretches), fatigue limits (steel can work perpetually with deformations under a certain threshold). There's also specific strength (strength per kg) vs strength per volume and strength per dollar. Steel also comes in lots of different flavors, with…
> The researchers found that the new material’s elastic modulus — a measure of how much force it takes to deform a material — is between four and six times greater than that of bulletproof glass. They also found that its yield strength, or how much force it takes to break the material, is twice that of steel, even though the material has only about one-sixth the density of steel.
That's not yield strength.
Yield strength is how much force is required to permanently deform the material.
Ultimate tensile strength is the force required to break the material.
One great thing about steels is that they tend to work-harden.
Typical 250 grade mild steel, meaning it takes in excess of 250 MPa force to permanently stretch a 10mm round diameter section, usually has an ultimate tensile strength exceeding 400 MPa.
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Plenty of things are stronger than steel on a per pound basis. For instance, many aluminum alloys have about 60-80% the tensile strength of steel, but only 1/3rd the weight.
Titanium even more so. For those, they are actively swapped around where cost vs weight trade offs happen. steel vs aluminum vs magnesium, vs titanium in engineering application, where for example engine blocks, airplane parts, car parts, battery components, etc. all have a long history of this. It’s a complicated process because the trade offs are not simple cost/weight/strength. Steel has an nearly infinite fatigue…
> Titanium is in theory much better, but is incredibly difficult to work with(requiring forgings in most cases, and being almost unmachinable), and very expensive as the bond it forms with oxygen is so strong the normal fluorine based processing used with Aluminum won’t work. Yeah, you read that right.
I have a spoon bought from Amazon which they claim is made from titanium. [Lockheed_SR-71_Blackbird](https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird) claims 31 aircraft made from titanium and first flew in 1964. Given they got it off the ground in 1964 and can make a spoon in 2022 what kind of machining problems are left to solve for titanium? Usually it's the other way round like make s spoon from wood for 5,000 years then make an aircraft in 1905.
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It's potentially a thermoset plastic in which case it should be able to resist somewhat high temperatures (maybe 300C). So not fireproof but not terrible either.
As a comparison, various types of insulation are rated for 60/90 minutes at 1000 degrees Celsius, while some types of brick are rated for 180 minutes. If this material can't sustain similar temperatures, it's unlikely it will be used in construction.
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I'm intrigued. What's a vacuum airship?
https://en.m.wikipedia.org/wiki/Vacuum_airship Like a blimp but with a rigid balloon filled (ha ha) with vacuum instead of a light gas. The article is saying it's a polymer so I'm guessing it doesn't have the right rigidity, ie, the stronger than steel bit must be with respect to a different strength measure
A helium balloon makes sense, it's lighter than air so it floats, duh.
Well, what's lighter than that? Nothing (vacuum)! It's such a dumb, but correct answer that I had a hard time wrapping my head around it.
Yup, theoretically a vacuum would be extremely buoyant if we could put it in a light enough structure.