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Statements like this had me confused for years about how steel is made. Steel is raw iron ore with some carbon removed. (Among other things) Pure iron isn't common in nature, it's usually found instead with too much carbon. That is, to have the properties we like in steel.
> Tests showed the new alloy achieved a compressive yield strength of more than two gigapascals while retaining its ductility, meaning it bends without breaking. This is sleight-of-hand. For metals, the operative properties are usually ultimate tensile strength and tensile yield strength . Compressive strength is typically a non-factor for most engineering alloys; only concrete is judged by its compressive strength,…
> High compressive strengths are not very useful. I mean, it depends on the use case right? Modern tall buildings/skyscrapers with metal framing use metal pillars where high compressive strength is very useful.
For compressive strength alone to matter, you’d essentially need a solid steel column - which is so prohibitively heavy, it would often end up collapsing under it’s own weight (in tensile failure, most likely) before it got up to a useful height.
Earlier quoted context omitted.
As hard as ever. US and USSR and EU has this tech, China, India and others still don't. When USSR tech was sold left and right in 1990s, China could not replicate it, although they surely got the documentation back then. Even now they can't build a reliable gas generator from 70s and are stuck at 1960s level with R-25 MiG-21-style engine replicas. They still try and fail to build AL-31 analogs (1978, Su-27 engine).
This is an American-Pro forum, you will only get dislikes promoting the idea that USSR had any technology or morality matching or exceeding Western superiority ;)
In all fairness though, if your enemies are just Afghan tribemen of Vietnamese farmers with an AK you don't have much of an excuse for losing. But even then you can can the moral high ground because you value life more than them.
Yes, it's all propaganda. But they are distinct tools (approaches?). It's fine to say your enemy has better equipment though, because that gives you an excuse for more R&D and gives you an excuse if you didn't win, why the win took longer, why the win was 'honourable' despite the win seeming inevitable by every conventional metric.
To be slightly more kind. I suppose you could argue this helps the peace afterwards.
If you say the beaten adversary was a worthy opponent, they can help keep their heads high. The Allies are now friends with Germany and Japan. I'm sure some reframing comes along with that.
"Steel is one of the classic alloy examples: mostly iron with a dash of carbon and other elements, making it much stronger and harder than iron on its own." Statements like this had me confused for years about how steel is made. Steel is raw iron ore with some carbon removed . (Among other things) Pure iron isn't common in nature, it's usually found instead with too much carbon. That is, to have the properties we lik…
"Steel" is defined as carbon content between .02% and 2%. If the metal has less than that it's wrought iron. If it had more than that it's cast iron.
So steel is a range of carbon contents that gives particularly useful properties.
Historically the lower end of that was higher but with that addition of other alloys we have "low carbon steels" that behave like steel with very little carbon.
> Tests showed the new alloy achieved a compressive yield strength of more than two gigapascals while retaining its ductility, meaning it bends without breaking. This is sleight-of-hand. For metals, the operative properties are usually ultimate tensile strength and tensile yield strength . Compressive strength is typically a non-factor for most engineering alloys; only concrete is judged by its compressive strength,…
This is really cool metallurgy. They start with an alloy and deform it and because of elemental size mismatch they can cause the alloy to self assemble into nanoscale crystals with three different structures The paper: https://www.science.org/doi/10.1126/science.aec4995 As an aside, “super alloy” is not the best wording choice on the part of the author of this sciencealert article, superalloys are an established allo…
This is really cool metallurgy. They start with an alloy and deform it and because of elemental size mismatch they can cause the alloy to self assemble into nanoscale crystals with three different structures The paper: https://www.science.org/doi/10.1126/science.aec4995 As an aside, “super alloy” is not the best wording choice on the part of the author of this sciencealert article, superalloys are an established allo…
This is basic metallurgy that every metal forger and alloy designer is already aware of.
There’s some precedent for mechanical deformation to get nanocrystalline grain structure, and some precedent for mechanically induced phase transformations (see TrIP steels) but I consider both of those concepts pretty advanced
TrIP is probably the closest thing, but I’m not sure how widely known there are among the “metal forging” community? TrIP is usually targeting well known phase transformations to two-phase microstructures, here we have three nanostructured phases.
Finally high entropy alloys are absolutely not well understood, even if the idea of mixing a lot of elements and getting a disordered solution seems simple on its face.
Earlier quoted context omitted.
> High compressive strengths are not very useful. I mean, it depends on the use case right? Modern tall buildings/skyscrapers with metal framing use metal pillars where high compressive strength is very useful.
Interestingly, the design of beams and the like (used for columns) still means tensile strength is the limiting factor, not compressive strength. For compressive strength alone to matter, you’d essentially need a solid steel column - which is so prohibitively heavy, it would often end up collapsing under it’s own weight (in tensile failure, most likely) before it got up to a useful height.
Earlier quoted context omitted.
Absolutely nobody is using an expensive novel alloy for 2GPa compressive strength. A 2GPa tensile strength, depending on various other factors such as corrosion resistance and thermal properties, could however be very interesting. (The strongest bulk steel alloys generally peak at ~3.6GPa tensile, which is approximately their theoretical maximum, but there are a lot of applications where steel simply can't be used. N…
That's true, but it's still factor and if price comes down having that much compressive strength at your disposal could be an interesting choice for supertall skyscrapers.
Also, the price of a Ta-Hf-Zr-Nb-Ti alloy isn't especially elastic. Tantalum in particular is an unavoidably expensive element.
I'll grant that what would be exceptional is a metal with a >2GPa compressive strength, a >2GPa tensile strength, and decent damage tolerance and ductility. I don't think that this paper describes a material with that outstanding combination of properties, though -- it's much more likely to describe a simple brittle material.