19 Apr 01

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19 Apr 01

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Course Administration. 1. 19 Apr 01. Take home final to be issued early next week. ... Course Administration. 6. Texture development in brass? ... – PowerPoint PPT presentation

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Title: 19 Apr 01

1
19 Apr 01

Take home final to be issued early next week.
Florida in finals as of 23 Apr but Lehigh/CMU
continue until May 3rd.
No further homeworks (unless we change our
mind!).
Prof. G.S. Rohrer will give the last class on May
3rd, and will lecture on Atomic Force Microscopy
and related microscopies.

2
26th April 01

Today discussion on Yield Surfaces
Look for Anisotropy.pt3.YieldSurfaces (either ppt
or pdf).
If enough time Aniso.pt4.crystallography
Tuesday complete plastic anisotropy grain
growth theory. (1 May).
Thurs (3rd May) Prof. Rohrer AFM

3
17 April 01

This week step-by-step through LApp (Los Alamos
polycrystal plasticity) - a how-to guide. Notes
for some slides. See also the popLA.manual.pdf.
Reminder homework 6 on misorientations.
Emphasize that any programming method is
acceptable, including excel macros! Most
students seem to be able to do this email me
with questions.

4
10 April 01

Introduction to the Taylor model continues on
Thursday.
Next week step-by-step through LApp (Los Alamos
polycrystal plasticity) - a how-to guide.
Reminder homework 6 on misorientations.
Emphasize that any programming method is
acceptable, including excel macros!

5
27 Mar 01

Review session - any questions entertained from
the class.
Show movie on Texturing in the Earths Mantle.
Preview of homework (Hwk 6) on analysis of grain
boundary character.
Recap of tilt-twist analysis.
No lecture on Thursday, 29 March (FL students in
OIM lab.).

Texture development in brass? What causes the
transition in texture from copper type to
brass type?
Still disagreement in literature! Not just
because of twinning. Why? E.g., in copper rolled
at low temperatures, you obtain brass texture.
Also been associated with planar versus
diffuse slip.

7
Mackenzie distribution

Where does it come from?
Why does it have the shape that it does?

8
Texture hardening?

Hardening mechanisms does texture count as a
hardening mechanism? Answer generally speaking,
texture is not hardening mechanism. Why? Cubic
materials range of Taylor factors is (approx.)
v6 - 4.5, i.e. range of Taylor factors is x2.
Lower symmetry materials depending on
deformation systems, range of Taylor factors can
be large factor of 4 or more.

9
Texture hardening, contd.

Texture (Taylor factor) this effect multiplies
any other hardening mechanisms. Why? Texture is
a geometrical Taylor factor multiplication
factor applied to critical resolved shear
stress.
Yield ltTaylor factorgt crss

10
22 March 01

Today discuss elastic anisotropy - example of a
linear property that depends on the
microstructure (primarily the texture).Anisotropy
.pt1.22Mar.ppt/pdf
For the grads review of properties of tensors.
Tensors(grads).22Mar.ppt/pdf

11
22 March 01

Where are we going? Explain the Taylor model for
plastic deformation of polycrystals this shows
how deformation textures arise and also what the
impact of texture and microstructure is on
mechanical anisotropy. Read the paper!
(available in Assignments as Taylor.1938.pdf)

12
Next Week

Next week review session on Tuesday cover any
topics missed last Tuesday by Fl/Drexel
(connection problems) review tilt/twist
analysis show video on Texturing of Rocks in
the Earths Mantle by Paul Dawson et al.
(Cornell).
Thursday FAMU/FSU to visit OIM lab. No lecture.

13
Feedback

Significant (low) scores
information clear, organized 4/3/5/4/3/2
instructor understood 5/2/2/4/4/2
constructive feedback 4/2/5/-/2/2
pitched at proper level 5/3/5/3/4/3
start/end on time 5/2/4/4/2/2
returning papers promptly 5/2/5/4/3/4
varying activities 5/4/5/4/4/2
address students by name 5/2/5/-/5/3

14
Response to feedback

information clear, organized better guides to
slides
instructor understood check audio connection?
constructive feedback please ASK!
pitched at proper level too advanced?
start/end on time limited by technology
returning papers promptly will try to improve
turn-around time
varying activities limited by technology
address students by name will make more effort
here

15
20 March 01

Today finish discussion of (a) grain boundary
properties (b) how to analyze the tilt-twist
character of boundaries.
Thursday/22 Mar start the discussion of
anisotropy with elastic anisotropy how to
calculate an average modulus.

16
20 Mar 01, contd.

1) grain boundary props GBproperties.8Mar.ppt/pd
f slides 32-45, 65. all students
2) tilt-twist analysis CSL.6Mar.ppt/pdf slides
4,5,12-22,48-54,60-61. all students
3) grain boundary props CSL.6Mar.ppt/pdf slides
41,46-65. grad students
If time permits, I'll go back to g.b. props with
the grads and say more about properties (balance
of slides in GBproperties.8Mar.ppt).

17
20 March 01, contd.

Mid-term
Q1 generally well answered, although very few
people thought to include the basic equation that
describes the defocussing correction that is so
very different from bulk samples.
Q2. A few people came up with odd values for
angles, suggesting that their version of hkl2eul
was not functioning correctly.

Q3. No problems here.
Q4. The only issue here was that not everyone
showed the algebraic working to make the
connection between Miller indices and Euler
angles.
Q5. This question was answered well by
essentially everyone. There were some variations
in assumptions about cell centering but this was
acceptable based on the wording of the question.

Q6. This question was the most problematic. Not
everyone was able to get the hkl2eul program to
function correctly. With the symmetry operator
files, it appears that some did not copy the
header line that specifies the number of symmetry
operators, causing the code to think that there
was only one operator in any file. CUB.SYM
should have 24, and ORT.SYM, for example, should
have 4 operators. The last section (v) also was
harder to do than I expected and will need to be
re-written in a future version. It turned out to
be difficult to find orientations that clearly
demonstrated the expected variation in spread as
a function of the second angle.

Q7. The answers to this question were highly
variable. Those who plunged in and worked on the
algebra, mostly did quite well (and I
incorporated the alternative results in the
solution set). Some were able to find the
standard position of the alpha fiber but did not
know how to proceed on the 0,-1,1 case. In any
case, I hope that you find the answer interesting
and instructive, especially when you look
carefully at the Miller index charts.

21
8 Mar 01

todayMar 8th. What is a Coincident Site Lattice?
CSL boundaries grads CSL theory
CSL.6Mar.ppt/pdf
Mar. 6 Finish Grain Boundaries misorientations
Rodrigues vectors, space
Mar. 8th Gbproperties.8Mar.ppt/pdfGrain
boundary properties energy, mobility grads
tilt vs. twist character

22
6 March 01

todayMar 6th. Finish Grain Boundaries
misorientations Rodrigues vectors, space
today Mar. 1st grads active vs. passive
rotations for misorientation
Mar. 6, today What is a Coincident Site Lattice?
CSL boundaries grads CSL theory
Mar. 8th Grain boundary properties grads tilt
vs. twist character

23
1 March 01

today finish Herrings Relations for Triple
Junctions extension to velocities
today Mar. 1st Grain Boundaries
misorientations Rodrigues vectors, space grads
quaternions
Mar. 6 What is a Coincident Site Lattice? CSL
boundaries grads CSL theory
Mar. 8th Grain boundary properties grads tilt
vs. twist character

Q. part b) with the formula given in class
(topology 22feb.ppt) -- I am getting negative
values for Nv(D) for group numbers 1, 2, and 3.
for dnL/dl, I used delta nL/delta l, where delta
is the difference between that group number's
value and the preceeding group number's value.
Is that the correct method?
A. The formula should lead you to calculate
nL/delta l/l-average, where l-average is the
average value of the length in the interval (i.e.
upperlower/2). You should then obtain
reasonable values of Nv in all the intervals,
i.e. be able to reproduce the graph given.

25
Q. part c) the question asks to calculate the
distribution. are we simply supposed to plot nL
vs. l, or are we supposed to calculate a formula
for the distribution, e.g. sigma values etc.? A.
No, no curve fitting expected, just a plot of Nv
versus l size.
26

Q. part d) if we calculate Na from table 4.2 for
a truncated octahedron, are we supposed to plot
that vs. l, or is there something else we're to
do?
A. I made a mistake in writing this part of the
question. Obtaining size distributions for
non-spherical particles is not addressed in
Underwoods book, and although there are some
approximate results that could be obtained (with
Table 4.2, for example), it is not worth pursuing
at this stage.

27
27 Feb 01

today finish Stereology Herrings Relations for
Triple Junctions extension to velocities grads
capillarity vector
Mar. 1st Grain Boundaries misorientations
Rodrigues vectors, space grads quaternions
Mar. 6 What is a Coincident Site Lattice? CSL
boundaries grads CSL theory
Mar. 8th Grain boundary properties grads tilt
vs. twist character

28
20 Feb 01

Discussion of textures from thermomechanical
processing today Ch. 5 in the Kocks book.
AOL inst. Messenger adrollett
Metals.texture.pt2/3.20Feb.ppt (or pdf) available
WEBCAST /telab.web.cmu.edu/dan/rollett.html

29
15 Feb 01

Still working on the links to FL but continuing
with re-broadcast from FSU/FAMU.
Discussion of textures from thermomechanical
processing today Ch. 5 in the Kocks book.
Survey approach to provide a background
Metals.texture.pt1/2/3.15Feb.ppt (or pdf)
available

30
15 Feb 01, contd.

Resolution of pdf files increased.
Next lecture(s) will be on stereology I.e.
quantitative microscopy taken from Underwoods
on Quantitative Stereology.
Recently, Ive been using PICT format for the
images this apparently does not work on PCs.
Therefore I will switch to JPEG at 300 dpi (e.g.
in Distiller).

31
8 Feb 01

Phone 412 268 3179
2nd 3rd homework due today.
Example of application to archeometallurgy
(astrolabes).
Discussion of symmetry effects continued.- Minor
updates on symmetry.6Feb.ppt/pdf files to be
posted soon.

32
8 Feb 01, contd.

Next topic textures from thermomechanical
processing (Ch. 5 in Kocks).
Posted metals.textures.8Feb.ppt/pdf- several
parts to this (part,part3 posted - more to come)
because of large image files.
Coming soon a pdf file with the paper crystal
from II-VI.- also, Hwk 4 to be posted before
the weekend due Feb 20th (Tues?)

33
6 Feb 01

Phone 412 268 3179
3rd homework posted, due Thurs. 8th.
2nd homework can be delayed until Thurs (snow
day, Monday at Lehigh! Read your email for
corrections)
Demo of Euler angles
Discussion of symmetry effects (detail)

Will move on to survey of experimental textures
in next lecture (ahead of schedule)
Grads discussion of rotations w.r.t. pole
figures
Reading Chapter 2 in Kocks covers much of
current discussion
Reading ahead Ch. 5 (Kocks)discusses textures
in metals, (Ch. 4 in geological materials).

35
Analysis of PF data w/popLA

Original aim use popLA to analyze a real set of
pole figure data. Would prefer to do this when I
know that everyone can do it.
Question is there someone at Lehigh ( Drexel?)
who is willing to volunteer to download the (DOS)
software and get it running? Also, who at
FSU/FAMU is willing to be a contact for popLA?
David Waryoba?

36
1 Feb 01

rollett_at_andrew.cmu.edu/ 412 268 3179
We (still) have a videoconference link between
CMU and FSU/FAMU working on the 3-way link.
Realserver feed available at www.eng.fsu.edu/servi
ces/cmu/
2nd homework due Tuesday, 6th, because of delays
in transmission.
3rd homework posted, due Thurs. 8th.

37
Adv. Charac. Microstructural Analysis 25 Jan
01

The plan for this week continues we will
videoconference between CMU and FSU/FAMU.
APOLOGIES to students at Lehigh! We are still
having technical difficulties with
videoconference links (incompatibilities in data
transmission rates between the 3 sites).

Latest ppt pdf files uploaded 830am.
PDF files of the two papers mentioned in the
first homework will be loaded this afternoon.

39
Links 22 Jan 01

The plan for this week we will videoconference
between CMU and FSU/FAMU.
APOLOGIES to students at Lehigh! We are having
technical difficulties with videoconference links
(nobody can dial in to Florida). I understand
that you have no sound today if you can watch on
your own PC (not in the classroom?), you should
get sound.

40
Question about Hwk. 1

Answer for QU 1a. Is incorrect I forgot to
normalize the vector! Should be (1/v2,1/v2,0).
Thank you!

41
Blackboard info

Go to //courseinfo.web.cmu.edu/
Login (last name is usually what I used for your
ID)
Download powerpoint files as you please
WEBCAST /telab.web.cmu.edu/dan/rollett.html

42
Course Administration

23 Jan. 01
TA for Advanced Characterization
Microstructural AnalysisSoonwuk Cheong, 412 268
8797, scheong_at_andrew.cmu.edu
1st homework due on Thurs, 25 Jan. 01
Powerpoint files can now be downloaded

43
Why Offer a Course on Advanced Characterization
and Microstructural Analysis?

The Materials Research, Science Engineering
Center at Carnegie Mellon supports an
interdisciplinary research group (IRG) called the
Mesoscale Interface Mapping Project (MIMP).
The MIMP is partnered with FSU/FAMU, Brigham
Young Univ., and Lehigh (among others).

44
MIMP purpose

The MIMPs purpose is to measure the properties
of grain boundaries (and other interfaces) in
sufficient detail that Grain Boundary Engineering
(GBE) can be conducted on a quantitative basis.
In its broadest sense, GBE is about obtaining the
microstructure-with-texture that optimizes a
given application.

45
Course Objective

Course aimed at providing basic tools for
pursuing the aims of MIMP texture,
microstructural characterization, analysis, grain
boundary analysis, anisotropy, engineering
application.

46
Lecture Schedule week 1

Jan. 16th Introduction to Microstructure,
including texture examples of engineering
problems involving texture orientation as
rotation PFs
Jan. 18th Measurement of pole figures,
theoretical construction of PFs
Homework construction of PFs projections

47
Lecture Schedule week 2

Jan. 23rd Concept of Orientation Distribution
OD maps Euler angles discrete vs. functional
ODs Groups (elementary theory for graduate
students)
Jan. 25th Volume fractions alternate
definitions of Euler angles relation of ODs to
PFs conversion from Miller indices to angles
Homework exercises on locating components,
volume fractions

48
Lecture Schedule week 3

Jan. 30th Texture Components different
representations, especially matrices rotations,
transformations relationships between them
Feb. 1st Fiber textures, example of fiber
textures in thin film Cu.
Homework exercises in conversion from one form
of representation to another.

49
Lecture Schedule week 4

Feb. 6th Different methods of representing ODs
square, polar plots Symmetry
Feb. 8th Sample vs. Crystal Symmetry Effect of
symmetry on Representation of Texture
Homework exercises on conversion between
different representations of orientation (last
years hwk 1)

50
Lecture Schedule week 5

Feb. 13th no lecture
Feb. 15th Effect of symmetry on Representation
of Texture
Homework calculation of ODs from measured
textures calculation of volume fractions

51
Lecture Schedule week 6

Feb. 20th The origin and causes of texture in
thin films (primarily deposition)
Feb. 22nd The origin and causes of texture in
bulk materials (primarily thermomechanical
processing)
Homework literature search

52
Lecture Schedule week 7

Feb. 27th Functions to represent texture
Fourier transforms spherical harmonics
Mar. 1st Fundamental equation of texture
harmonic method, WIMV method, others
Homework plotting spherical harmonics

53
Lecture Schedule week 8

Mar 6th Tensors recapitulation of algebra of
tensors transformations
Mar. 8th Anisotropy basic equation(s) for
linear anisotropy Elastic Anisotropy
Homework mastery of tensor algebra

54
Lecture Schedule week 9

FSU/FAMU is on Spring Break also Lehigh U. no
live classes
Mar. 13th In-class demonstration of effect
sample symmetry with popLA
Mar. 15th Demonstration of polycrystal
plasticity calculations (LApp)
Homework exercises on elastic anisotropy
(probably from Courtney or Nye)

55
Lecture Schedule week 10

Mar. 20th Greg Rohrer Atomic Force Microscopy
(AFM)
Mar. 22nd Brent Adams Applications of elastic
anisotropy limits on elastic anisotropy
Week 11 PK _at_ FSU/FAMU Lab Intensive Sessions
CMU Spring Break no live classes

56
Lecture Schedule week 12