3D Atom Probe Characterization of Nanoscale Precipitation

The 3D atom probe (3D-AP) is the configuration of the Field Ion Microscope (FIM) operated as time-of-flight mass spectrometer. Surface atoms are field desorbed by a nanosecond high voltage pulse and accelerated to the screen. The time of flight is a measure for the mass, the synchronously recorded impact point is the projection of the original position in the lattice. From the data set a chemically resolved image can be mapped out in three dimensions.
The formation of very fine precipitates (typically 1 to 3 nm) labeled as dispersion hardening is one of the most powerful means in strengthening steels. The 3D atom probe brings up an unrivaled atomic level insight into this precipitation phenomena.

Precipitation in a tool steel,  Ne ion image at  40 K, 40 nm Ø area

Matrix of a tool steel, 3D reconstruction of AP data 10 nm Ø area, 200 atomic layers in depth

Blow up view of a primary Precipitate  (mainly W and C), ~5nm2 area plotted

Blow up view of a secondary Precipitate (mainly Cr and C),  ~5nm2area plotted

Collaborations

Institut für Metallkunde und Werkstoffprüfung, Montanuniversität Leoben
Forschungszentrum für Elektronenemikroskopie, TU Graz

Recent Publication

M. Leisch, “Three-dimensional nanoscale analysis in physical metallurgy”
Vacuum 67(2002)435-442