Papers by Keyword: FIB Tomography

Abstract: In the present work a quantitative analysis of γ' and γ" phase nanoparticles in Inconel 718 was performed using two methods of electron tomography, namely EFTEM and FIB tomography. 3D visualisation showed that γ' particles are spherical, while γ" precipitates are disc-shaped. The values of mean size of γ' and γ" phase particles, determined by both electron tomography methods applied, are in good agreement.

Abstract: A typical dual-beam platform combines a focused ion beam (FIB) microscope with a field emission gun scanning electron microscope (FEGSEM). Using FIB-FEGSEM, it is possible to sequentially mill away > ~ 50 nm sections of a material by FIB and characterize, at high resolution, the crystallographic features of each new surface by electron backscatter diffraction (EBSD). The successive images can be combined to generate 3D crystallographic maps of the microstructure. A useful technique is described for FIB milling that allows the reliable reconstruction of 3D microstructures using EBSD. This serial sectioning technique was used to investigate the recrystallization behaviour of a particle-containing nickel alloy, which revealed a number of features of the recrystallizing grains that are not clearly evident in 2D EBSD micrographs such as clear evidence of particle stimulated nucleation (PSN) and twin formation and growth during PSN.

Abstract: A typical dual-beam platform combines a focussed ion beam (FIB) microscope with a field emission gun scanning electron microscope (FEGSEM). Using this platform, it is possible to sequentially mill off > ~ 50 nm slices of a material by FIB and characterise, at high resolution, the crystallographic features of each new surface by electron backscatter diffraction (EBSD). The successive images can be combined to generate 3-D crystallographic maps of the microstructure. This paper describes various aspects of 3-D FIB tomography in the context of understanding the microstructural evolution of metals during deformation and annealing. The first part of the paper describes the influence of both metal type and milling parameters on the quality of EBSD patterns generated from a surface prepared by FIB milling. Single crystals of some face centred cubic metals were examined under varying FIB milling parameters to optimise EBSD pattern quality. It was found that pattern quality improves with increasing atomic number with the FIB milling parameters needed to be adjusted accordingly. The second part of the paper describes a useful technique for FIB milling for the reliable reconstruction of 3-D microstructures using EBSD. There is an initial procedure involving extensive milling to generate a protruding rectangular-shaped volume at the free surface. Serial sectioning is subsequently carried out on this volume. The technique was used to investigate the recrystallization behaviour of a particle-containing nickel sample, which revealed a number of features of the recrystallizing grains that are not clearly evident in 2-D EBSD micrographs.