Atom Probe Tomography: Methodology and Application

Atom probe tomography (APT) permits a three-dimensional analysis of species distribution with nearly atomic resolution. Due to recent development of the technique, it is now possible, by the application of short laser pulses, tear ion by ion from the surface of an oxide specimen. Thus, investigations of the metal-oxide interfaces became possible. In this presentation APT as a technique and its possibilities for materials research will be introduced with a focus on investigations of NiAl-alloys with additions of B, Ti, Y, Hf.
APT investigations revealed the presence of Ni and Cr in the GBs, suggesting that these could be stemming from outward diffusion from the metal. To investigate the contribution of this process, also concerning the reactive elements, in comparison to the dominating inward diffusion of O and the minor outward diffusion of Al a series of exposure experiments was conducted.