Stabilization of nanocrystalline alloys at high temperatures via utilizing high-entropy grain boundary complexions

Multicomponent alloying can be utilized to enhance the thermal stability of nanocrystalline alloys. The grain boundary energy can be reduced significantly via both bulk and grain-boundary high-entropy effects with increasing temperature at/within the solid solubility limit, thereby reducing the thermodynamic driving force for grain growth. Moreover, grain boundary migration can be hindered by sluggish kinetics. To test these new theories, numerical experiments were conducted; subsequently, several nanoalloys, including a Ni-based alloy (Ni80Mo6.6Ti6Nb6Ta1.4) and Ni-containing high-entropy alloys (Ni29Fe23Co23Cr23Zr2 and Ni25Fe23Co23Cr23Mo2Nb2Zr2), were designed and fabricated to demonstrate outstanding thermal stabilities that outperform the Ni-based binary nanocrystalline alloys. (C) 2016 Elsevier Ltd. All rights reserved.