An international research team has developed a new “high-entropy” metal alloy with a higher strength-to-weight ratio than any other existing metal material.

The researchers combined lithium, magnesium, titanium, aluminum and scandium to make a nanocrystalline high-entropy alloy that has low density, but very high strength.

"The density is comparable to aluminum, but it is stronger than titanium alloys," says Dr. Carl Koch, Kobe Steel Distinguished Professor of Materials Science and Engineering at NC State and senior author of a paper on the work.

“It has a combination of high strength and low density that is, as far as we can tell, unmatched by any other metallic material. The strength-to-weight ratio is comparable to some ceramics, but we think it's tougher - less brittle - than ceramics.”

There are plenty of good uses for such strong, lightweight materials - in vehicles, prosthetic devices, surgical implants, and even construction.

“We still have a lot of research to do to fully characterise this material and explore the best processing methods for it,” Koch says.

At this point, the main problem with the alloy is that it is made of 20 percent scandium, which is extremely expensive.

“One thing we'll be looking at is whether scandium can be replaced or eliminated from the alloy,” Koch says

The full report on the development is accessible here.