I don’t think the title is terribly accurate or enlightening but ….

South Korean researchers have solved a longstanding problem that stopped them from creating ultra-strong, lightweight aluminium-steel alloys.
From shipping containers to skyscrapers to turbines, good old steel is still the workhorse of our modern world. Now, scientists are discovering new secrets to make the material better, lighter, and stronger.

Today a team of material scientists at Pohang University of Science and Technology in South Korea announced what they’re calling one of the biggest steel breakthroughs of the last few decades: an altogether new type of flexible, ultra-strong, lightweight steel. This new metal has a strength-to-weight ratio that matches even our best titanium alloys, but at one tenth the cost, and can be created on a small scale with machinery already used to make automotive-grade steel. The study appears in Nature.

“Because of its lightness, our steel may find many applications in automotive and aircraft manufacturing,” says Hansoo Kim, the researcher that led the team.

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Now, this is more like the 21st century is supposed to be.

Thanks, Bill.

Of course the title begs the question “which titanium?” Some titanium alloys are pretty weak.

From link:
… In the 1970’s, Soviet researchers discovered that adding aluminum to the mix when creating steel can make an incredibly strong and lightweight metal, but this new steel was unavoidably brittle. You’d have to exert lots of force to reach the limit of its strength, but once you did, the steel would break rather than bend. Scientists soon realized the problem: When creating the aluminum-steel alloy, they were occasionally fusing atoms of aluminum and iron together to form tough, crystalline structures called B2. These veins and nuggets of B2 were strong but brittle. The scientists calculated that if small B2 crystals were separated from one another, then the surrounding alloy would insulate them from splintering.

Good work. Some work in Australia had previously concentrated on the problem that high strength in metals such as steel is correlated with high brittleness, and found that the link could be broken by using microcrystalline metals. That didn’t work well for bulk metals because the minimum crystal size is limited by the cooling rate, but it does work beautifully for tough strong thin surface coatings of metal.

Interesting.

But the suggestion that a material can be significantly lighter than steel, but still be steel, makes me sceptical.

The final product of all this tinkering “is 13 percent less dense compared to normal steel, and has almost the same strength-to-weight ratio compared to titanium alloys,”

So still steel, but nowhere near light enough for applications where low weight is important then.