Revealing atomic-scale vacancy-solute interaction in nickel

TL;DR

This study combines microscopy, atom probe tomography, and theoretical calculations to reveal how tantalum atoms interact with vacancies in nickel, explaining enhanced creep resistance in Ta-alloyed nickel materials.

Contribution

It provides direct experimental and theoretical evidence of solute-vacancy binding in nickel-tantalum alloys, advancing understanding of atomic-scale interactions affecting material properties.

Findings

Tantalum atoms show a positive correlation with vacancies in nickel.

Solute-vacancy binding explains improved creep resistance.

Experimental and theoretical methods confirm the interaction.

Abstract

Imaging individual vacancies in solids and revealing their interactions with solute atoms remains one of the frontiers in microscopy and microanalysis. Here we study a creep-deformed binary Ni-2 at.% Ta alloy. Atom probe tomography reveals a random distribution of Ta. Field ion microscopy, with contrast interpretation supported by density-functional theory and time-of-flight mass spectrometry, evidences a positive correlation of tantalum with vacancies. Our results support solute-vacancy binding, which explains improvement in creep resistance of Ta-containing Ni-based superalloys and helps guide future material design strategies.