Site-specific specimen preparation for atom probe tomography of grain boundaries

Atom probe tomography is a powerful technique that is highly suited to the study of low-level grain boundary segregation. However, difficulties in preparation of the required needle-shaped specimens containing the area of interest have precluded detailed studies of this nature to date. Two new methods are presented to manufacture atom probe tips from site-specific areas using a dual-beam focused ion beam (FIB)/scanning electron microscope (SEM). One involves the use of electropolished blanks, which are resharpened using the ion beam, and the second utilises micromanipulators to lift the area of interest directly from a bulk specimen before ion beam fabrication of the tip. The advantages and drawbacks of each technique are compared. (c) 2007 Elsevier B.V. All rights reserved.