Title: The Focused Ion-Beam Tool for site-Specific Atom-Probe Tomography Analysis of CU Alloys

Speaker: Jessica Riesterer, NECIS Student, University of Minnesota

Date/Time: Tuesday, August 22, 2006, 2:30 – 3:00 pm (PT)

Location: Bldg. 915, Room, W133 (Sandia-CA)

Brief Abstract: Grain boundary triple junctions have been shown to impact the behavior of grain boundaries, but very limited experimental experiments have been carried out to understand dopant segregation at triple junctions and the driving forces at play. Characterizing triple junctions can be very challenging. Only a few limited transmission electron microscopy observations have been reported so far. Because of the three-dimensional character of triple junctions, atom probe tomography would be the technique of choice, providing atom-by-atom three-dimensional mapping of small volumes of material. We are therefore developing techniques to prepare atom probe specimens containing triple junctions and grain boundaries of known character. After annealing to promote diffusion of dopants within the Cu samples and ensure stability of the boundary structures, site-specific atom probe tips containing grain boundaries and triple junctions are prepared. The analyzed boundaries and junctions are characterized by electron backscatter diffraction (EBSD) prior to focused-ion beam milling of the areas of interest.

CSRI POC: Doug Medlin, (925) 294-2825