Sometimes the biggest change in metalmaking comes from turning the heat down.
An international team of researchers says it has developed a new way to build alloys, using lower, more controlled temperatures and a set baking time to produce a stronger, more stable metal.
The method is described in a paper published in Science. The researchers say it can produce metals several times stronger than widely used materials today.
In the study, the team mixed five metals, hafnium, niobium, tantalum, titanium and zirconium. After a brief high-temperature melting stage, the alloy was cooled to 550 degrees Celsius and left for several hours and even days.
The best result came at about 32 hours, when the researchers produced a Refractory High-Entropy Alloy, or RHEAD. The study says it was two times stronger than steel, three times stronger than aluminium, and twice as strong as the same alloy made in a conventional way.
The researchers said the lower-temperature process let atoms settle into a more stable, ordered arrangement in small, tightly packed grains.
“For more than a century, alloy development has focused on composition and processing,” materials scientist Jian-Feng Nie from Monash University said.
“Our work suggests that how atoms organize during manufacturing may be just as important.
“The real significance is not just this particular alloy, but the demonstration that atoms can self-organize into defect-free structures in a bulk metallic material, meaning a large, continuous piece of metal, not a thin coating, film or microscopic sample.”
The study says that scaling up small, well-organized grains into a usable material has been a challenge in earlier work.
It says the choice of metals and the preparation method created conditions for the atoms to arrange themselves into repeating grain patterns, forming a structure free from defects.
Tests showed the new alloy reached a compressive yield strength of more than two gigapascals while retaining its ductility.
“By carefully controlling how the atoms organize during processing, we were able to create a highly connected structure with exceptional strength and stability,” materials scientist Yu Zhang from Chongqing University said.
Nie said the approach could have broader uses in alloy design.
“If this concept can be applied more broadly, it could open the door to materials with properties that were previously considered unattainable, with implications for alloy design that could be applied across many systems and industries,” he said.
“Instead of increasing alloy content to achieve better performance, we may be able to design internal structures that deliver superior properties with fewer alloying elements. That could lead to more efficient, sustainable, and cost-effective alloy production.”
The researchers said they next want to understand not only how the atoms rearrange themselves, but why.
“For more than a century, advances in alloys have come from altering the chemical composition and processing, guided largely by empirical trial and error,” Yiannis Ventikos, Dean of Engineering at Monash University, who was not directly involved in the study, said.
“This research suggests we can actually engineer how atoms organize themselves, creating opportunities to develop materials with capabilities that were previously out of reach.”
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