Joseph T. McKeown

Crystallographic Orientation Image Mapping with Multiple Detector Configurations at 30 - 300 kV

The acquisition of 2D diffraction patterns from an array of 2D points in a scanning electron beam experiment is a 4D experiment that can be used to map local crystallographic orientations. The automated acquisition and analysis of these Kikuchi diffraction patterns [1, 2] has enabled orientation mapping of crystals with a large range of length scales. For example, commercially available electron back-scattered diffraction (EBSD) systems for an SEM are capable of measuring micronand submicron–scale features over length scales of 1 cm using automated montaging techniques. However, the pursuit of crystallographic features that are 10 nm or smaller requires the use of transmission-based techniques available in both SEM and TEM. There have been several advancements in automated analysis of diffraction patterns that have enabled the ability to perform automated Kikuchi diffraction experiments in a variety of microscope configurations [3-6]. At accelerating voltages of 30 kV and lower, it is now possible to perform transmission Kikuchi diffraction (TKD) experiments using a conventional EBSD detector and an SEM to study features 10 nm and smaller. In addition, the use of scanning precession electron diffraction (PED) has enabled experiments with similar spatial resolutions for spot diffraction patterns in TEMs at accelerating voltages of hundreds of kV.

Using Energy-Filtered TEM to Solve Practical Materials Problems with Inspirations from Gareth Thomas

1 Sandia National Laboratories, Livermore, CA, USA 2 Materials Science and Engineering, Stanford University, Stanford, CA, USA 3 Sandia National Laboratories, Albuquerque, NM, USA 4 Lawrence Livermore National Laboratory, Livermore, CA, USA 5 Materials Science and Engineering, University of CA, Berkeley, CA, USA 6 Nanotechnology and Functional Materials Center, University of Belgrade, Belgrade, Serbia

Spatially confined alloy single crystals for model studies of volumetrically constrained phase transformations

The authors present a method to fabricate confined, oriented, single crystals of ternary alloys within an inert ceramic matrix. Pulsed-laser deposition of a polycrystalline CuNiFe film fills lithographically defined surface cavities in a sapphire single crystal. Solid-state diffusion bonding to a second sapphire crystal internalizes the metal-filled cavities. Electron microscopy verifies that subsequent heat treatment converts the thin, fully constrained films into single crystals of specific orientation by nucleation-controlled liquid-phase epitaxy during cooling from above the alloy melting temperature. The resulting films provide an ideal medium for fundamental studies of a wide range of volumetrically constrained phase transformations.