Characterising the nature and density of dislocations in materials using routine EBSD mapping

Effective characterisation of atomic-scale dislocations is important to understand a crystalline material’s physical properties, its processing or natural history, or its suitability for certain applications. This applies to processed metals and alloys, where formation and movement of dislocations associated with certain slip systems can control the deformation and strength of the material; to geological samples, where the nature of dislocations informs us about conditions during tectonic processes; and in semiconductors, where dislocations formed during thin-film growth can adversely affect performance.

Characterisation of dislocation types and their densities using electron backscatter diffraction (EBSD) has become increasingly popular in recent years. Various techniques exist for extracting dislocation information from EBSD data, some involving time-consuming diffraction pattern correlation approaches and many others requiring assumptions about the type of dislocations present in the sample. In Oxford Instruments’ AZtecCrystal EBSD data processing software, we have developed a new Dislocation Analysis tool that utilises the “weighted Burgers vector” (WBV) approach, developed by Prof. John Wheeler from Liverpool University. The WBV technique is free from assumptions about dislocation type, provides crucial information about Burgers vector orientation (and hence slip system activity or growth processes) and can be used to provide a lower limit for geometrically necessary dislocation densities.

In this webinar, you will learn: 

• The key principles behind the Weighted Burgers Vector approach
• How the WBV tool has been implemented in AZtecCrystal
• Application examples across a wide range of research fields, covering dislocations formed during deformation and during growth