HR (high angular resolution) EBSD and strain measurement software – Crosscourt 3
Scientists and associates are continually pushing for improved analytical capabilities to better understand their materials. BLG Vantage has responded by creating a unique, powerful and easy to use product that enables the measurement of strain at the microscopic level – providing data never before possible!
- Map residual strain at the full spatial resolution of your EBSD system
- Determine the full strain and rotation tensors to 1 part in 10,000 precision
- Measure lattice misorientation to better than 1/100 degree
- Calculate all 9 stress components and the Mises Stress
- Analyse metals, semiconductors & mineralogical samples from all crystal systems
- Produce High Resolution Kernel Average Misorientation Maps (HR KAM)
- Map GND distributions (Geometrically Necessary Dislocations)
- Import data from Bruker CrystAlign, EDAX OIM, Oxford Instruments Inca and AZtec EBSD data collections systems
- Export all results to Excel or Matlab for further analysis
- Uses cross correlation techniques to measure EBSD pattern shifts to 1/20 pixel resolution
- Access 2 separate measurements of the data quality
- Easily adjust measurement parameters before and after cross-correlation
Residual strain is a microstructural parameter which is of considerable importance but historically difficult to measure. Fortunately, recent advances in Electron Backscatter Diffraction have now made possible strain quantification at both high precision and accuracy. Cross correlation between EBSD patterns obtained from strained and unstrained regions of a crystal can be used to measure normal and shear strains at the 1 part in 10000 level.
CrossCourt 3 is a software package that determines the full strain tensor and local strain gradient in single and polycrystalline specimens by measuring the distortion of EBSD patterns recorded in sequence across the sample. The EBSD patterns are collected using either the EDAX_TSL OIM DC or Oxford_HKL data collection systems.
The cross correlation method has been tested and proven accurate through a large number of studies. The example shown here is of the stress distribution adjacent to a crack induced in germanium.
The release of CrossCourt 3 marks the culmination of five years of the development and testing of this technique.
Stress distribution adjacent to a lenticular crack in germanium.
Elastic shear strain distribution surrounding carbide precipitate in Ni Base alloy. (x10-4)
Recent published studies have included mapping grain boundary strain in polycrystalline Ni base alloys, strains adjacent to fatigue cracks, and strains surrounding carbide precipitates in the annealed and post deformation stages. In the semiconductor field strain measurements have been determined in both plan view and cross section for SiGe/Si gate structures and ELOG GaN blue lasers.
Extension to NBD
To extend the spatial resolution limit below the 60nm level possible with EBSD, the CrossCourt3 software has been adopted for use with Nano Beam Diffraction Patterns. It functions in a similar way to the proven EBSD method by comparing an NBD pattern from a strained area with that from a reference unstrained area.The effect on strain measurement of differences in diffraction pattern centre and spot shape are minimized using an auto correlation function applied to patterns from both the strained and the unstrained reference areas. The method takes advantage of the high current, well collimated beam and extremely small probe size achievable in a modern dedicated STEM system.
Analysis of this pattern taken in a Hitachi 2300 STEM, allowed us to determine the normal strains parallel to  and  directions, the shear strain in the (1-10) plane and rotation about [1-10].
The Data opposite was collected using a 2kx2k video camera fitted to an Hitachi S2300 microscope.Beam control and diffraction pattern collection were made using EDAX_TSL OIMDC software.CrossCourt3 calculates all strain values automatically and provides output as two dimension micrographs or one dimensional line traces.
If you would like more information about Crosscourt 3 and developments now click here