A new class of high entropy Invar alloys

Ziyuan Rao and his colleagues win Editor's Choice selection

April 26, 2021

A face-lift for Invar alloys tailored as 3D high-entropy alloys just by choosing the proper valence-electron-concentration.

A hydrogen based economy requires materials with high mechanical strength and toughness at cryogenic temperatures.  They must also have very low thermal expansion, to avoid mechanical stresses and catastrophic failure of structures upon temperature change (e.g. when used for cryogenic gas storage and transport).

Such materials are called Invar alloys and are still used today and were not changed since their invention by Charles Edouard Guillaume, awarded with the Nobel Prize 1920.

In a recent paper,  Ziyuan Rao, researcher in the department "Microstructure Physics and Alloy Design" at the MPIE, and his colleagues in the same department, the Mugla Sitki Kocman University and the University Duisburg-Essen take a new approach at this material class, combining Invar properties with some of the most promising high-entropy alloy features, namely, high mechanical strength and excellent corrosion resistance.

Their recent paper has been picked as editor's choice in the journal Physical Review Materials.

1.
Ziyuan Rao, Aslı Çakır, Özge Özgün, Dirk Ponge, Dierk Raabe, Zhiming Li, Mehmet Acet
3d transition-metal high-entropy Invar alloy developed by adjusting the valence-electron concentration
Phys. Rev. Materials 5, 044406 – Published 16 April 2021
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