EBSD - now a standard microscopy technique for materials characterisation

Full text: Although the electron backscatter diffraction (EBSD) technique has been known for nearly 50 years and used frequently for over a decade, it has remained the domain of a few research scientists in materials science and geology. However, in the past 1 -2 years there have been significant developments that make EBSD more accessible as a standard microanalytical tool. These developments can be split into 2 groups: reliability and speed. Although the majority of EBSD analyses are still carried out on 'simple' materials such as aluminium, nickel and steel, increasingly researchers wish to analyse more difficult materials. These may be multi-phase alloys, low symmetry minerals or particulate phases of varying compositions. Improvements in EBSD software coupled with enhancements in CCD camera technology allow the routine analysis of these more complex materials with a high degree of reliability and accuracy. These advances also allow the use of EBSD, coupled with chemical information (for example from the EDS or WDS techniques), as a tool to identify unknown phases on the basis of their crystallography. Less than 2 years ago, automated EBSD analyses were typically being carried out at speeds of 1-5 points every second. This either restricted users to the analysis of small areas, or else necessitated very long sessions of SEM use. Dramatic improvements in software and hardware now allow the collection of EBSD data at rates of well over 25 points per second, with minimal loss of data accuracy or reliability. This enables users to collect relatively detailed orientation maps within 1 hour, or to analyse very large areas (i.e. over 1 million data points) in a single overnight scan. Continued developments in the next few years will further improve the acquisition speed of the EBSD technique. This paper will focus on how recent developments in both speed and reliability are now making EBSD a standard microanalytical tool for the characterisation of materials. Examples will be shown illustrating recent improvements in system performance, with a focus on the increasing numbers of applications of the EBSD technique. Copyright (2002) Australian Society for Electron Microscopy Inc