Enhanced radiation damage tolerance of amorphous interphase and grain boundary complexions in Cu-Ta

TL;DR

This study uses atomistic simulations to show that amorphous interphase complexions in Cu-Ta alloys significantly improve radiation damage tolerance by reducing defect accumulation, with complexion thickness being a key factor.

Contribution

It demonstrates that amorphous interphase complexions in Cu-Ta alloys enhance radiation resistance, highlighting the importance of interfacial engineering and complexion thickness control.

Findings

Amorphous complexions reduce residual defect damage compared to ordered interfaces.

Thicker interfacial films increase damage tolerance by altering defect production.

Amorphous complexions exhibit heterogeneous atomic excess volume distribution.

Abstract

Amorphous interfacial complexions are particularly resistant to radiation damage and have been primarily studied in alloys with good glass-forming ability, yet recent reports suggest that these features can form even in immiscible alloys such as Cu-Ta under irradiation. In this study, the mechanisms of damage production and annihilation due to primary knock-on atom collisions are investigated for amorphous interphase and grain boundaries in a Cu-Ta alloy using atomistic simulations. Amorphous complexions, in particular amorphous interphase complexions that separate Cu and Ta grains, result in less residual defect damage than their ordered counterparts. Stemming from the nanophase chemical separation in this alloy, the amorphous complexions exhibit a highly heterogeneous distribution of atomic excess volume, as compared to a good glass former like Cu-Zr. Complexion thickness, a tunable structural descriptor, plays a vital role in damage resistance. Thicker interfacial films are more damage-tolerant because they alter the defect production rate due to differences in intrinsic displacement threshold energies during the collision cascade. Overall, the findings of this work highlight the importance of interfacial engineering in enhancing the properties of materials operating in radiation-prone environments and the promise of amorphous complexions as particularly radiation damage-tolerant microstructural features.