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SUMMARY:Exploring the world with high angular resolution electron backscat
 ter diffraction (HR-EBSD) - Ben Britton\,Department of Materials\, Imperia
 l College London
DTSTART:20160118T140000Z
DTEND:20160118T150000Z
UID:TALK63215@talks.cam.ac.uk
CONTACT:Duncan Johnstone
DESCRIPTION:The advent of precise\, high fidelity and automated tools for 
 electron microscopy provides exciting new opportunities to engineer the wo
 rld around us. In particular we can carefully measure\, characterise and u
 nderstand the interplay of microstructure and properties to drive mechanis
 tic understanding at a wide range of length scales. One such technique emp
 loyed routinely within the scanning electron microscope (SEM) is electron 
 backscatter diffraction (EBSD). Diffraction patterns are captured as the e
 lectron probe is scanned across the surface of a well-polished crystalline
  sample and maps of microstructure\, including distributions of crystal or
 ientation\, morphology and phase can be generated easily with commercially
  available software tools based upon the Hough transform and typical cryst
 al misorientation precision is 0.5 degrees. The typical spatial resolution
  of the technique is ~100nm.\n\nFor an even deeper understanding of the mi
 crostructure-performance-properties paradigm\, the diffraction patterns ca
 n be analysed using sophisticated image processing algorithms to extract h
 igher precision information concerning misorientation within grains and ul
 timately elastic strain (and through Hooke's law\, stress). This is achiev
 ed through cross correlation of two or more diffraction patterns\, providi
 ng increased sensitivity of two orders of magnitude\, and enables (deviato
 ric) elastic strains of ~1E-4 and lattice misorientations of 0.006 degrees
  (~1E-4 rads) to be measured.\n\nIn this talk\, I will introduce the overa
 ll technique including the recent remapping approach and outline our appro
 aches to understand precision\, accuracy and sensitivity within grains and
  near grain boundaries. This will be followed by a few case studies includ
 ing: a combined study with high spatial resolution digital image correlati
 on to recover components of the complete deformation gradient tensor\, F\;
  measurement of geometrically necessary and total dislocation density in m
 etals and semiconductors\; and finally an examination of dislocation pile-
 ups near grain boundaries in titanium.\n
LOCATION:LT Goldsmith 1 Materials Science and Metallurgy\, Department of
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