ICAMS / Interdisciplinary Centre for Advanced Materials Simulation

Research Highlights

Imaging individual solute atoms at crystalline imperfections in metals

S. Katnagallu, L. T. Stephenson, I. Mouton, C. Freysoldt, A. P. A. Subramanyam, J. Jenke, A. N. C. Ladines, S. Neumeier, T. Hammerschmidt, R. Drautz, J. Neugebauer, F. Vurpillot, D. Raabe, B. Gault.

Directly imaging all atoms constituting a material and, maybe more importantly, crystalline defects that dictate materials' properties, remains a formidable challenge. Here, we propose a new approach to chemistry-sensitive field-ion microscopy (FIM) combining FIM with time-of-flight mass-spectrometry (tof-ms). Elemental identification and correlation to FIM images enabled by data mining of combined tof-ms delivers a truly analytical-FIM (A-FIM). Contrast variations due to different chemistries is also interpreted from density-functional theory (DFT). A-FIM has true atomic resolution and we demonstrate how the technique can reveal the presence of individual solute atoms at specific positions in the microstructure. The performance of this new technique is showcased in revealing individual Re atoms at crystalline defects formed in Ni–Re binary alloy during creep deformation. The atomistic details offered by A-FIM allowed us to directly compare our results with simulations, and to tackle a long-standing question of how Re extends lifetime of Ni-based superalloys in service at high-temperature.

Interaction of Re solute atom with edge dislocation in Ni as obtained by tight-binding calculations (available via license CC-BY 3.0).