ORIENTATION IMAGING MICROSCOPY (OIM) - SOME CASE STUDIES

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ORIENTATION IMAGING MICROSCOPY (OIM) - SOME
CASE STUDIES
EML 5930 (27-750) Advanced Characterization and
Microstructural Analysis A. D. Rollett, P.N Kalu,
D. Waryoba Spring 2006
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OUTLINE

• REVIEW OF OIM
• CASE STUDIES
• Development of Polishing Technique For OIM Study
  of Heavily Deformed OFHC Copper
• Recrystallization in Heavily Deformed OFHC Copper
• Heavily Deformed Cu-Ag
• Deformed and Annealed OFHC Copper
• Deformed and Annealed Cu-Nb
• Other Examples

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INTRODCUTION TO OIM - Diffraction
Diffraction of inelastically scattered electrons
by lattice planes (hkl) according to Braggs
law Sections of a pair of Kossel cones form a
pair of parallel straight Kikuchi lines on the
flat phosphor screen. For maximum intensity, the
specimen surface is steeply tilted at an angle of
20-30 from grazing incidence.
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INTRODCUTION TO OIM - EBSP formation
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INTRODCUTION TO OIM - Data acquisition
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TECHNIQUE DEVELOPMENT
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TECHNIQUE DEVELOPMENT

• EBSPs from a sample prepared by standard
  metallographic technique Polished

(a) OIM grain boundary map and (b) EBSD patterns
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TECHNIQUE DEVELOPMENT

• EBSPs from a sample prepared by standard
  metallographic technique Polished etched

(a) OIM grain boundary map and (b) EBSD patterns
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TECHNIQUE DEVELOPMENT

• EBSPs from a sample prepared by Novel technique -
  Polished Etched Polished

(a) OIM grain boundary map and (b) EBSD patterns
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Image Quality
Confidence Index
Confidence Index
Image Quality
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TECHNIQUE DEVELOPMENT

• CONCLUSIONS
• Polishing by the novel technique, which consists
  of polishingetchingpolishing, produced high
  quality EBSPs leading to excellent OIM image.

• IPF from OIM were consistent with the IPF from
  X-ray diffraction

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Rex in HEAVILY DEFORMED OFHC COPPER
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Rex in HEAVILY DEFORMED OFHC COPPER

• Microstructure

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Rex in HEAVILY DEFORMED OFHC COPPER
OIM map showing grain orientations at (a) ?p
2.3, ?UTS 411.5 MPa, and (b) ?p 3.2, ?UTS
405 MPa. The lines represent high angle
boundaries, with misorientation gt 15o.
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Rex in HEAVILY DEFORMED OFHC COPPER
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lt213gt75 -3 11 6lt-65-2gt
lt112gt54 -265lt-12 22 7gt
lt-4-13gt45 1 11 18lt7 29 2gt
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lt313gt85 184lt-12 17 2gt
lt12-6gt40 -4-19lt-46-3gt
lt1-21gt26 -212lt-34-5gt
lt1-1-3gt48 -8713lt25-3gt
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lt-1-15gt56 -2 14 23lt13 11 1gt
lt-211gt63 3-4 11lt6 10 3gt
lt144gt60 -6 13 5lt-24-2gt
lt-210gt36
lt1-1-1gt64 -201lt23-8gt
lt112gt65
lt-1-12gt60 198lt12 23 2gt
lt2-1-2gt52
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lt2-1-1gt65
lt-1-12gt60
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lt-210gt32
lt2-1-3gt55
lt313gt66
lt4-2-1gt42
lt133gt65
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Rex in HEAVILY DEFORMED OFHC COPPER
OIM map showing grain orientations after
deformation to ?p 3.6, ?UTS 390.5 MPa.
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Color Key
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Sh/B in HEAVILY DEFORMED OFHC COPPER
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Rex in HEAVILY DEFORMED OFHC COPPER

• CONCLUSION
• Three regions were identified
• Low processing strain ? lt 2.5 No
  recrystallization, elongated structure.
• Intermediate strain 2.5 lt ? lt 3.2 Nucleation of
  recrystallization, shear bands formation. Shear
  bands occurred in grains with S123lt634gt
  orientation, and were inclined at 54 to the
  drawing direction. Their misorientation was
  between 5??s?10.
• High strain ? gt 3.2 Extended recrystallization,
  recrystallized grains were mainly of Cube
  001lt100gt and S123lt624gt orientations.
• OIM proved to be a viable tool in the study of
  heavily deformed materials.

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HEAVILY DEFORMED Cu-Ag
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HEAVILY DEFORMED CuAg
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HEAVILY DEFORMED Cu-Ag
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DEFORMED AND ANNEALED OFHC COPPER
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ANNEALED OFHC COPPER - Microstructure
(a) Optical micrograph of annealed Cu, ?p 3.1,
750C
(a) Optical micrograph of annealed Cu, ?p 3.1,
350C
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ANNEALED OFHC COPPER
OIM tiled IPF map showing grain orientations for
Cu wire drawn to a strain of 3.1 and annealed at
250C for 1 hr.
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Color Key
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ANNEALED OFHC COPPER
OIM tiled IPF map showing grain orientations for
Cu wire drawn to a strain of 3.1 and annealed at
300C for 1 hr.
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ANNEALED OFHC COPPER
OIM tiled IPF map showing grain orientations for
Cu wire drawn to a strain of 3.1 and annealed at
500C for 1 hr.
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ANNEALED OFHC COPPER
OIM tiled IPF map showing grain orientations for
Cu wire drawn to a strain of 3.1 and annealed at
750C for 1 hr.
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ANNEALED OFHC COPPER OIM-IPF
(a) Deformed Cu, ?p 2.3
(b) Deformed Cu, ?p 3.1
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(a) Annealed Cu, ?p 3.1, 250C
(b) Annealed Cu, ?p 3.1, 300C
(d) Annealed Cu, ?p 3.1, 750C
(c) Annealed Cu, ?p 3.1, 500C
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DEFORMED AND ANNEALED Cu-Nb/Ti
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DEFORMED AND ANNEALED Cu-Nb/Ti
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DEFORMED AND ANNEALED Cu-Nb/Ti
Annealed CuNb, ?p 3.1, 250C (Nb phase
extracted)
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DEFORMED AND ANNEALED Cu-Nb/Ti
Annealed CuNb, ?p 3.1, 300C
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DEFORMED AND ANNEALED Cu-Nb/Ti
Annealed CuNb, ?p 3.1, 500C
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DEFORMED AND ANNEALED Cu-Nb/Ti
Annealed CuNb, ?p 3.1, 750C
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Other Examples
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