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World-First 'Super Alloy' Could Transform the Way Metals Are Made

93 points by tejohnso

by rsfern

3 subcomments

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 alloy family that follow a different design strategy and have a very different composition profile https://en.wikipedia.org/wiki/Superalloy

by A_D_E_P_T

2 subcomments

> 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, and sometimes various engineering ceramics. (e.g. SiC, compressive strength = 3.9 GPa.)
About ten years ago, there were a lot of papers on amorphous metal alloys that had "extreme strength" -- compressive strengths in the 5-6 GPa range -- but tensile strength was not reported and very low. Some measure of ductility was also present, but it too was very low. Those amorphous alloys were classical brittle materials; more ceramic-like than metal-like. I fear the same is probably the case here, with the alloy potentially fracturing along crystal type grain boundaries.
Until they report actual tensile strength and elongation, don't believe the hype. High compressive strengths are not very useful.

by htlemur_bobby

4 subcomments

Hm I just read an article here recently that was saying that Americans had an edge in jet turbine blades production over china because Americans figured out how to make single crystal jet turbines using this same method. I wonder what the difference is.

by iandanforth

1 subcomments

"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 like in steel.

by fwlr

2 subcomments

Presumably, some initial information was fed into the start of this reporting process. Multiple stages of this process had near-total incomprehension of the information yet performed full ingestion and reconstitution of it anyway, leading to this terminally-confused output.

by MeteorMarc

0 subcomment

Not only the initial strength is important but also the susceptiveness to crack growth during many years of stress. No idea how this structure would perform on this aspect.

by prewett

1 subcomments

I guess I'm not impressed that some totally different alloy is stronger than steel. You can't change both method and alloy and claim that the method is better. Presumably the paper compared the same alloy using the normal and the new method, but this article omitted that essential information, and in so doing destroyed the result.

by calibas

0 subcomment

This will be very useful if they can find a way to make it without something that costs $12,000 per kg.

by ChoGGi

0 subcomment

I see they mention scaling up and time, something tells me this is cost prohibitive.

by anenefan

1 subcomments

Interesting for products where the resulting alloy just needs machining - lathing, milling, drilling etc, but more interesting will be what processes will be needed to weld or form such alloyed metals.

by marethyu

1 subcomments

by SV_BubbleTime

3 subcomments

by bitwize

2 subcomments

Now all we need to do is build an invincible giant robot out of it, to protect peace and justice from the forces of evil.
https://en.wikipedia.org/wiki/Mazinger_Z
https://en.wikipedia.org/wiki/Chogokin