Materials

"Super steel" breakthrough makes for stronger and tougher alloy

"Super steel" breakthrough mak...
Professor Huang Mingxin shows a sample of the new super steel
Professor Huang Mingxin shows a sample of the new super steel
View 4 Images
Professor Huang Mingxin shows a sample of the new super steel
1/4
Professor Huang Mingxin shows a sample of the new super steel
The new super steel has superior strength and toughness
2/4
The new super steel has superior strength and toughness
Liu Li (left) and Huang Mingxin (right), demonstrating the new super steel
3/4
Liu Li (left) and Huang Mingxin (right), demonstrating the new super steel
The new super steel's fracture resistance is tested
4/4
The new super steel's fracture resistance is tested
View gallery - 4 images

It’s a frustrating fact that whenever you try to improve materials like steel, you end up introducing new weaknesses at the same time. It’s a balancing act between different properties. Now, engineers have developed a new type of “super steel” that defies this trade-off, staying strong while still resisting fractures.

For materials like steel, there are three main properties that need to be balanced – strength, toughness and ductility. The first two might sound like the same thing, but there’s an important difference. Strength describes how much of a load a material can take before it deforms or fails, measured in Pascals of pressure. Toughness, meanwhile, measures how much energy it takes to fracture a material.

For reference, glass has relatively high strength but low toughness, so it’s able to support quite a bit of weight but it doesn’t take much energy to break.

And finally, ductility is a measure of how easy it is to extend or elongate a material into different shapes. Unfortunately, improving one of these three properties tends to lessen another. Boosting strength, for instance, often makes a material less tough or ductile.

Liu Li (left) and Huang Mingxin (right), demonstrating the new super steel
Liu Li (left) and Huang Mingxin (right), demonstrating the new super steel

But now, researchers at the University of Hong Kong and Lawrence Berkeley National Labs (LBNL) say they’ve managed to produce a type of steel that has high-level performance in all three properties. And they boldly call it “super steel.”

The new material has a yield strength resistance against deformation of around 2 GigaPascals, a fracture toughness of 102 MPa-m½, and a uniform elongation of 19 percent. The team says this makes the super steel stronger and tougher than the Grade 300 maraging steel used in aerospace engineering – and the new steel only costs about 20 percent of the price to manufacture.

The super steel is made using a new deformed and partitioned method (D&P), and it gets its toughness from a unique design feature. When a fracture appears at the surface of the material, multiple tiny cracks form below it. These micro-cracks go on to absorb the energy from external forces, which prevents the main fracture from spreading too quickly.

The new super steel's fracture resistance is tested
The new super steel's fracture resistance is tested

The team says that the new super steel could find use in high-strength bridge cables, bullet-proof vests, and car springs, among other applications.

“We have made a big step closer to industrializing the novel super steel,” says Huang Mingxin, lead author of the study. “It demonstrates a great potential to be used in various applications including superior bulletproof vests, bridge cables, lightweight automobile and military vehicles, aerospace, and high strength bolts and nuts in the construction industry.”

The research was published in the journal Science.

Source: University of Hong Kong

View gallery - 4 images
8 comments
moreover
I'm especially intrigued about the potential for light weighting which has been a primary research objective for ARPA-e. Lower weights have cascading positive effects in transportation, especially now that EV cars and planes have to counter the weight of their batteries.
Expanded Viewpoint
So... what is the recipe for this new super steel alloy??
Username
They should have named it Rearden Metal!
guzmanchinky
Just when you thought steel has been around so long that you couldn't possibly make it any better...
Jason Rye
Did they think to invent a new variety of carbide to machine this new Super Steel with? Maybe I should just ask if a new cutting material would be required to machine it. Cool advancement!
SibylTheHeretic
Call SpaceX, they like stainless steel.
Martin Hone
Lacking any detail so can only assume this is from their PR Dept.
Karmudjun
Low on specifics but very high on the WOW factor! Can't wait to understand more about this super steel and I wonder how many decades before it is as commonplace as carbon-fiber construction.