famu-fsu college of engineering department of mechanical engineering 1 orientation imaging...

1FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

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

2FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

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

3FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

INTRODCUTION TO OIM - Diffraction

Diffraction of inelastically scattered electrons by lattice planes (hkl) according to Bragg’s 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.

4FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

INTRODCUTION TO OIM - EBSP formation

5FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

INTRODCUTION TO OIM - Data acquisition

6FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

TECHNIQUE DEVELOPMENT

7FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

TECHNIQUE DEVELOPMENT

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

EBSPs from a sample prepared by standard metallographic technique: Polished

8FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

TECHNIQUE DEVELOPMENT

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

(b)(a)

EBSPs from a sample prepared by standard metallographic technique: Polished + etched

9FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

TECHNIQUE DEVELOPMENT

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

(b)(a)

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

10FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

Image Quality

Image Quality

Confidence Index

Confidence Index

11FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

TECHNIQUE DEVELOPMENT

IPF of wire drawn OFHC copper deformed to = 3.2, obtained via (a) OIM and (b) X-ray diffraction techniques

CONCLUSIONS Polishing by the novel technique, which consists

of polishing+etching+polishing, produced high

quality EBSPs leading to excellent OIM image.

IPF from OIM were consistent with the IPF from

X-ray diffraction

12FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

Rex in HEAVILY DEFORMED OFHC COPPER

13FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

Rex in HEAVILY DEFORMED OFHC COPPER

Optical micrograph showing microstructure after deformation to = 3.2, = 405 MPa. Arrows show pockets of recrystallized grains.

Microstructure

Optical micrograph showing microstructure after deformation to = 1.3, = 392 MPa. No recrystallization

14FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

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 > 15o.

U

X

V

Y

W

DD

(b)(a)

15FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

Rex in HEAVILY DEFORMED OFHC COPPER

16FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

1

10

1112

13

<313>85°{184}<-12 17 2>

<12-6>40°{-4-19}<-46-3>

<213>75°{-3 11 6}<-65-2>

<1-1-3>48°{-8713}<25-3>

<1-21>26°{-212}<-34-5>

<112>54°{-265}<-12 22 –7>

<-4-13>45°{1 11 18}<7 29 2>

<-1-12>60°{198}<12 23 2>

<1-1-1>64°{-201}<23-8>

<144>60°{-6 13 5}<-24-2>

<-1-15>56°{-2 14 23}<13 11 –1><-211>63°

{3-4 11}<6 10 3>

<112>65°

<-210>36°

<-210>32°

<133>65° <4-2-1>42° <313>66°

<-1-12>60°

<2-1-2>52°<2-1-1>65°

<2-1-3>55°

17FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

Rex in HEAVILY DEFORMED OFHC COPPER

OIM map showing grain orientations after deformation to p = 3.6, UTS = 390.5 MPa.

18FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

Color Key

19FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

Sh/B in HEAVILY DEFORMED OFHC COPPER

1

2

OIM maps of a heavily drawn Cu ( = 3.2) showing regions of shear bands.

Shaded IQ map of a heavily drawn Cu ( = 3.2) showing regions of shear bands.

20FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

21FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

Rex in HEAVILY DEFORMED OFHC COPPER CONCLUSION

Three regions were identified: Low processing strain < 2.5: No recrystallization,

elongated structure.

Intermediate strain 2.5 < < 3.2: Nucleation of recrystallization, shear bands formation. Shear bands occurred in grains with S{123}<634> orientation, and were inclined at 54° to the drawing direction. Their misorientation was between 5°s10°.

High strain > 3.2: Extended recrystallization, recrystallized grains were mainly of Cube {001}<100> and S{123}<624> orientations.

OIM proved to be a viable tool in the study of heavily deformed materials.

22FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

HEAVILY DEFORMED Cu-Ag

23FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

Optical micrograph of a heavily drawn CuAg ( = 3.2) showing regions of shear bands.

Shaded IQ map of a heavily drawn CuAg ( = 3.2) showing regions of shear bands.

HEAVILY DEFORMED CuAg

24FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

HEAVILY DEFORMED Cu-Ag

1

2

OIM maps of a heavily drawn CuAg ( = 3.18) showing regions of shear bands. The Grain boundaries were constructed with a misorientation criteria of 15°.

25FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

DEFORMED AND ANNEALED OFHC COPPER

26FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

ANNEALED OFHC COPPER - Microstructure

(a) Optical micrograph of annealed Cu, p = 3.1, 350°C

(a) Optical micrograph of annealed Cu, p = 3.1, 750°C

27FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

ANNEALED OFHC COPPER

OIM tiled IPF map showing grain orientations for Cu wire drawn to a strain of 3.1 and annealed at 250°C for 1 hr.

28FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

Color Key

29FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

ANNEALED OFHC COPPER

OIM tiled IPF map showing grain orientations for Cu wire drawn to a strain of 3.1 and annealed at 300°C for 1 hr.

30FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

ANNEALED OFHC COPPER

OIM tiled IPF map showing grain orientations for Cu wire drawn to a strain of 3.1 and annealed at 500°C for 1 hr.

31FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

ANNEALED OFHC COPPER

OIM tiled IPF map showing grain orientations for Cu wire drawn to a strain of 3.1 and annealed at 750°C for 1 hr.

32FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

ANNEALED OFHC COPPER: OIM-IPF

(a) Deformed Cu, p = 2.3 (b) Deformed Cu, p = 3.1

33FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

(a) Annealed Cu, p = 3.1, 250°C (b) Annealed Cu, p = 3.1, 300°C

(c) Annealed Cu, p = 3.1, 500°C (d) Annealed Cu, p = 3.1, 750°C

34FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

DEFORMED AND ANNEALED Cu-Nb/Ti

35FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

DEFORMED AND ANNEALED Cu-Nb/Ti

SEM micrograph of a heavily drawn Cu-Nb ( = 3.2) annealed at 500°C.

SEM micrograph of a heavily drawn Cu-Nb ( = 3.2) showing elongated Cu and Nb phases.

36FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

DEFORMED AND ANNEALED Cu-Nb/Ti

Annealed CuNb, p = 3.1, 250°C

(Nb phase extracted)

37FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

DEFORMED AND ANNEALED Cu-Nb/Ti

Annealed CuNb, p = 3.1, 300°C

38FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

DEFORMED AND ANNEALED Cu-Nb/Ti

Annealed CuNb, p = 3.1, 500°C

39FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

DEFORMED AND ANNEALED Cu-Nb/Ti

Annealed CuNb, p = 3.1, 750°C

40FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

Other Examples

41FAMU-FSU College of EngineeringDepartment of Mechanical Engineering

42FAMU-FSU College of EngineeringDepartment of Mechanical Engineering