Elemental partitioning and site-occupancy in γ/γ′ forming Co-Ti-Mo and Co-Ti-Cr alloys

Im, H.J. and Makineni, S.K. and Gault, B. and Stein, F. and Raabe, D. and Choi, P.-P.

Volume: 154 Pages: 159-162
DOI: 10.1016/j.scriptamat.2018.05.041
Published: 2018

We report on the sub-nanometer scale characterization of Co-12Ti-4Mo and Co-12Ti-4Cr (at.%) model alloys. Atom probe tomography reveals that Co and Cr partition to γ, whereas Ti and Mo to γ′. Additions of Mo and Cr to the reference Co-12Ti system lead to strong increases in γ′ volume fraction by about 25% and 12%, respectively. Element-specific spatial distribution maps along the [001] direction of the L12-ordered γ′ phase reveal that both Mo and Cr preferentially replace Ti on its sublattice. The remaining excess Ti is available for formation of additional γ′, resulting in enhanced γ′ volume fractions. © 2018 Elsevier Ltd

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