Beating hydrogen with its own weapon: Nano-twin gradients enhance embrittlement resistance of a high-entropy alloy

By Hong Luo, Wenjun Lu, X. Fang, D. Ponge, Zhiming Li, Dierk Raabe. Materials Today, 2018

183 citations recorded by the source corpus.

Abstract High-entropy alloys have shown exceptional damage tolerance at cryogenic temperatures. Here we report that this essential property can be maintained even when exposing the equiatomic CoCrFeMnNi alloy to the most detrimental environmental condition known to metals, hydrogen. This is enabled by a self-accommodation mechanism: the higher the local hydrogen content, the higher the twin formation rate as hydrogen reduces the stacking fault energy. Thus, the hydrogen’s through thickness diffusion gradient translates into a nano-twin gradient that counteracts material weakening by enhanced local strengthening. The concept targets applications under harsh and cryogenic conditions, such as encountered in arctic, offshore, energy and liquid gas chemical processing, and transport operations. The new mechanism opens a pathway to the design of alloys that withstand heavy mechanical loading under cryogenic and hydrogen-containing conditions.

Subfields: Aerospace Engineering, Mechanical Engineering, Mechanics of Materials

View Paper: https://www.semanticscholar.org/paper/efb70de83a002a05dacc5b71517e724900c6a4a5