Scientists at North Carolina lead by Professor Koch have developed a new ‘high-entropy’ metal alloy that has a higher strength-to-weight ratio than any other existing metal material. They combined lithium, magnesium, titanium, aluminum and scandium to make a nanocrystalline high-entropy alloy that has low density as Aluminum, and stronger than titanium. The main obstacle is to replace scandium in the alloy because of its high cost. This newly developed high entropy alloy can be potential used in vehicles and medical devices.
Materials Research Letters, 2014; 1.
Khaled M. Youssef1, Alexander J. Zaddach2, Changning Niu2, Douglas L. Irving2 & Carl C. Koch2*
1 Department of Materials Science and Technology, Qatar University, PO Box 2713, Doha, Qatar.
2 Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695-7907, USA.
A low-density, nanocrystalline high-entropy alloy, Al20Li20Mg10Sc20Ti30 was produced by mechanical alloying. It formed a single-phase fcc structure during ball milling and transformed to single-phase hcp upon annealing. The alloy has an estimated strength-to-weight ratio that is significantly higher than other nanocrystalline alloys and is comparable to ceramics. High hardness is retained after annealing.