Three-dimensional Analysis of Materials at Multiple Length Scales

One challenge of any microscopic technique is that the data generated is generally a two-dimensional slice or projection of a three-dimensional object. Typically, that two-dimensional image still provides a wealth of information about a materials’ or organism’s microstructure, but there are always limitations when trying to understand a specimen’s true three-dimensional nature. This motivates the need for many of the 3D materials characterization techniques and tools available today. A number of techniques are available that span decades in both voxel size/resolution and analyzed material volume [1]. I will discuss the use of electron microscopes for analyzing materials in three dimensions. In particular, I will show how electron tomography in the transmission electron microscope (TEM) is useful for analyzing the size and distribution of nanoscale He bubbles (~2 4 nm in diameter) in Pd that formed by tritium decay [2]. Figure 1 shows an example of 2D and 3D data collected on these nanoscale bubbles. In addition, I will show examples of serial sectioning in the FIB/SEM instrument and its use for simultaneously obtaining threedimensional morphological, compositional, and crystallographic orientation information with imaging, EDS, and EBSD. Examples in fuel cell device stacks [3] and laser-deposited stainless steel [4] will be presented that demonstrate the use of three-dimensional analysis.