Interstitial high entropy alloys

The recently introduced new materials class of high-entropy alloys (HEAs) consist of multiple principle elements. These materials provide a novel and promising avenue for realizing exceptional mechanical, physical and chemical properties.

We study a novel strategy for designing a new class of HEAs incorporating the additional interstitial element carbon. This results in joint activation of twinning- and transformation-induced plasticity (TWIP and TRIP) by tuning the matrix
phase’s instability in a metastable TRIP-assisted dual-phase HEA. Besides TWIP and TRIP, such alloys benefit from massive substitutional and interstitial solid solution strengthening as well as from the composite effect associated with its dual-phase structure. Nanosize particle formation and grain size reduction are also utilized. The new interstitial TWIP-TRIP-HEA thus unifies all metallic strengthening mechanisms in one material, leading to twice the tensile strength compared to a single-phase HEA with similar composition, yet, at identical ductility.

 

Interstitial atoms enable joint twinning and transformation induced plasticity in strong and ductile high-entropy alloys
Scientific Reports | 7:40704 | DOI: 10.1038/srep40704
Li_et_al-2017-Scientific_Reports interst[...]
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Acta Mat. 2011, 59, p. 364