Atom probe tomography of Ni-base superalloys Allvac 718Plus and Alloy 718
Journal article, 2011

Atom probe tomography (APT) allows near atomic scale compositional- and morphological studies of, e.g. matrix, precipitates and interfaces in a wide range of materials. In this work two Ni-base superalloys with similar compositions, Alloy 718 and its derivative Allvac 718Plus, are subject for investigation with special emphasis on the latter alloy. The structural and chemical nuances of these alloys are important for their properties. Of special interest are grain boundaries as their structure and chemistry are important for the materials' ability to resist rapid environmentally induced crack propagation. APT has proved to be suitable for analyses of these types of alloys using voltage pulsed APT. However, for investigations of specimens containing grain boundaries and other interfaces the risk for early specimen fracture is high. Analyses using laser pulsing impose lower electrical field on the specimen thereby significantly increasing the success rate of investigations. Here, the effect of laser pulsing was studied and the derived appropriate acquisition parameters were then applied for microstructural studies, from which initial results are shown. Furthermore, the influence of the higher evaporation field experienced by the hardening γ Ni3(Al,Nb) precipitates on the obtained results is discussed.

Delta phase

Gamma prime

Trajectory effects

Laser pulsing

Grain boundary segregation

Author

Leif Viskari

Chalmers, Applied Physics, Microscopy and Microanalysis

Krystyna Marta Stiller

Chalmers, Applied Physics, Microscopy and Microanalysis

Ultramicroscopy

0304-3991 (ISSN) 1879-2723 (eISSN)

Vol. 111 6 652-658

Driving Forces

Sustainable development

Subject Categories

Other Materials Engineering

Condensed Matter Physics

Areas of Advance

Materials Science

DOI

10.1016/j.ultramic.2011.01.015

More information

Created

10/6/2017