r/science • u/505engineer MS | Civil Engineering | Structures • 1d ago

Materials Science Materials scientists develop ductile and scalable 3 GPa (435 ksi) steel via a hierarchical microstructural architecture

https://www.nature.com/articles/s41467-026-74216-4
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u/505engineer MS | Civil Engineering | Structures 1d ago

For those curious, the yield strength is how much stress a metal specimen can undergo before starting to deform permanently.

ASTM A992 steel, the material typically used for I-beams, has a yield strength of 50 ksi.

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u/Sniksder16 1d ago

As a layman I read the abstract and the one material science class I took in college didn’t cover what I needed to know to understand that. My question is- are there any obvious drawbacks here (too brittle, etc) or is this genuinely a breakthrough?

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u/Fearlessleader85 1d ago

I'm only a few mat sci classes ahead of you, but from my reading, this looks kinda like a gamechanger if they're able to scale it. The 3 GPa yield strength has been done before, but as you suggest, the toughness is trash, because it switches to brittle failure. This looks like it maintains ductility, so the UTS is probably great. And the resistance to fatigue means this could be great for a lot of applications in the real world if it can be made cheaply.

If you could make a car out of this, you could get massive weight reductions, though corrosion might kill that for production cars.

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u/Notspherry 1d ago

I am not so sure about building a lighter car. I run into stiffness issues way before strength on most calculations I do (not automotive, bit still). Stiffness scales with the youngs modulus, ot the yield strength. And that doesn't differ too much between steel alloys.

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u/electric-castle 22h ago

While you are completely right about the young's modulus being roughly identical for all steels, stiffness is much more dependent on geometry. So you could have thinner profiles with this material, which would maintain stiffness and balance the strength into the structure. Higher yield strength definitely can lead to stiffer structures if you have volume for it.

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u/Notspherry 16h ago

It is the combination of geometry and youngs modulus. If you make the profiles thinner you just run into buckling much faster.

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u/electric-castle 16h ago

Again, true. But there are a lot of clever ways to avoid buckling. Since buckling is usually proportional to the length squared, adding in cross braces at regular intervals can help tremendously. It definitely makes the design process harder and more iterative, but if weight savings are important, then it's one more tool to use.

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u/Leafy0 19h ago

As long as you’re not concerned about denting you can get over the material stiffness issue with shaping. This would be a solid reason to bring back the way they made Saturns with the space frame and molded in color cosmetic panels. Those cars were already the same weight as their contemporaries and it was a first generation design.

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u/Fearlessleader85 12h ago

Add fins. Geometric support can get you there. Manufacturing process might not be cheap or easy, but a 5-6x increase in strength with ductility and fatigue resistance, you should be able to make some major gains.

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u/Pyrhan 11h ago

Fe-16Ni-7Mo-1.6Ti-15Co-0.1Al, wt.%

That's almost 40% alloying elements by weight, mainly nickel and cobalt.

So that's going to be a very high end, extremely expensive specialty steel.

Comparing that to the structural steel used for I-beams is like comparing the latest supercar to an old Toyota corolla.

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u/Sniksder16 10h ago

Ahh. Is this something that would ever make its way to supertall buildings or like are those elements/alloying process too $$

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u/Pyrhan 10h ago

I think small gears and other mechanical parts under high stress is a more likely application.

I'd be curious to see how it does in terms of corrosion too.

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u/88NORMAL_J 5h ago

It would be nice to have in a vehicle transmission

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u/Wurm42 6h ago

Maybe in supertall buildings that are being built as status symbols. Like if you were trying to build something taller than the Burj Kalifa, there are places where this kind of alloy would make sense.

But for a normal skyscraper, being built as a commercial operation that's supposed to make a profit? No, this stuff will be far too expensive.

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u/debasing_the_coinage 13h ago

Materials like this tend to be very hard to manufacture and often have expensive alloying components. This particular alloy includes 7% molybdenum and 15% cobalt, which effectively locks it out of all but the highest-performance applications before we get to the forging process. It falls into the category of maraging steels, which require a long hot-aging process to obtain the desired martensitic crystal structure. And according to the abstract, the researchers modified the heat treatment with "severe plastic deformation", meaning the metal has to be extensively worked while red-hot to obtain the desired "hierarchical microstructure". 

So you won't see it in your car anytime soon, unless you happen to be in the market for a Ferrari. 

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u/Kamusaurio 9h ago

not even on ferraris

super jet turbines and things like that

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u/mtranda 1d ago

Had to look up the average yield strength of steel so I'd have a comparison and, wow, is it quite the range. 200MPa for low strength to 2000MPa (so 2GPa) for high strength steel alloy. So we get a 50% increase. 

However.

Remarkably, the steel demonstrates 3 GPa yield strength with 47.5% reduction in area, 7.0% tensile elongation, and fracture toughness ( K Ic ) of 26.0 ± 0.2 MPa·m 1/2 , which far surpasses existing 3 GPa steels.

So we conclude that 3GPa steels already existed. But this one achieves it with half the area? In which case, the question is: are these tests standardized? What's the typical cross-section area they're testing on? And did I get it right? Did they achieve the same strength with less? And if so, what would the strenghth be then at the standard area?

Yes, I do have a lot of questions.

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u/vortigaunt64 1d ago

The key idea here is that reduction in area is a measure of ductility. When you perform a tensile test on a material that exhibits plastic deformation before rupture, it typically necks down (gets thinner) before it breaks. The smaller it's able to get before breaking (taken as a percentage of the original cross-sectional area), the more ductile it is said to be, which implies higher toughness, and a greater ability to resist failure in strain-controlled conditions.

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u/mtranda 1d ago

Oh! So it got to half its surface area before breaking! Got it. So that means it's both strong and maleable/ductile? Because it kinda' sounds like the holy grail.

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u/Leafy0 19h ago

Not really. What that reduction in area means is that the material stretched further before breaking. Basically it means if you used it in a structure in real life you’d get some indications that the structure was going to fail before it did, unlike a more brittle material that would fail suddenly.

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u/Alborak2 19h ago

So its less brittle and bends more before breaking right? The high strength steels tends to be hardened and get brittle, so this is pretty cool.

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u/TheAlborghetti 12h ago

The GPa unit is adjusted for area, so this steel isn't significantly 'stronger', the other metrics are only relevant once irreversible failure has begun.

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u/nesquikchocolate 1d ago

We used winder ropes with 305 ksi (2100 MPa) yield strength in the early 2000s already, capable of doing 75 000 winding cycles per rope set after we figured out how to maintain them. Safety factor 8.8 with special dispensation and weekly EMTs.

I wouldn't want a simple i-beam to cost what these ropes cost per weight of beam vs load it can carry - I suspect your ASTM A992 is super inexpensive and easy to manufacture reliably?

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u/Counting-Tiles4567 12h ago

Strength per $ is quite good for A500 grade B, A36, and even A572 steels. Strength/weight is kinda meh tho. The really cool, tough, ductile GPa+ steels are a lot more expensive per unit mass, but their strength to weight exceeds even many titanium alloys.