mechanical properties of materials lecture 01
TRANSCRIPT
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InstructorDr. Thomas Tsakalakos
Contact Information:
School of Engineering, Room A100
Tel: 848-445-2888
E-mail: [email protected]
14:635:407
Mechanical Properties of Materials
Section 02
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Venue & Time of the Class
Section: 02
Days: Mondays & Wednesday
Time: 17:00-18:20
Location: SOE-B120 Busch Campus
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Required Textbook
Materials Science &EngineeringAn I ntroduction
by
W.D. Callister
9thEdition
John Wiley & Sons
Book + CD needed
Supplementary mater ialswi l l be distr ibuted as needed.
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Office Hours
Dr. Tsakalakos:Mondays& Wednesdays
SOE-A100
14:00-15:30 or by appointment
Ross Rucker:Tuesdays
CCR-135
13:30-15:30 or by appointment
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Course Outline
Course Objective
Introduce fundamental concepts of materials
What you will learn
Structure of materialsHow structure affects properties
How processing affects structure
This course will help you to
Use/designate materials properly
Realize new design opportunities by proper
material selection
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Course Outline (Contd)Week/Dates Tuesday Thursday Reading
09/02-09/04 IntroductionAtomic Structure &Interatomic Bonding
Ch. 1/ Ch. 2
09/09-09/11Atomic Structure &Interatomic Bonding
The Structure ofCrystalline Solids
Ch. 2
09/16-09/18The Structure of Crystalline
Solids
Quiz + Structure/Crystal
DefectsCh. 3
09/23-09/25 Crystal Defects/dislocations Diffusion Ch.3/Ch. 4
09/30-10/2
Exam # 1 Mechanical properties Ch. 5
10/07-10/09Phase Diagrams/
Metals/Alloys
Phase Transformations Ch. 6/Ch.9
10/14-10/16 Ceramics Polymers Ch.10/11/12
10/21-10/23 Ceramics Composites Ch. 12-15
10/28-10/30 Exam #2Mechanical Properties/
Stress/Strain TensorCh. 16
11/4-11/6Mechanical Properties/
Constitutive LawsStrengthening Mechanisms
Ch. 7+
Add. Mat.
11/11-11/13 Fracture Mech./Failure Fracture/Fatigue/Creep Ch. 7/Ch. 8
11/18-11/20 Corrosion and Wear Time deformation/CreepCh. 8/
Add. Mat
11/25-11/27 Stress Corrosion/Cracking No class-Thanksgiving Ch. 8/Ch.17
12/02-12/04 Case Studies Case Studies
12/09-12/11 Case Studies Case Studies Ch. 19-22
12/16 Exam#3 No cl ass-End of Semester --
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Computer Requirement
Some classes may be be held at the
Design, Simulation and Visualization
(DSV) Computer Lab in room B-127 inthe Engineering Building.
All students are required to set up anaccount prior to the first computer
session.
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Grading
Weekly in-lecture 10min quizzes. 10% of finalgrade Once a week on Wednesdays based on the
previous
lecture.
(Lowest two quizzes will be dropped). Approx.
12 quizzes per semester.
Homeworks15% of final grade. Approx. 7-10.
No late homework accepted. Lowest HW score
dropped. Mostly for completion, but randomly
will be graded for a score.
Tests -25% of grade EACH. No final exam.
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Homeworks
a) If you have troubles, come ask!! BUT only
after the effort has been made.
b)
PDF or scanned copy are both accepted.c)
Submitted electronically to Sakai.
d) The HWs are to encourage you to learn the
material and prepare you for the tests.
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Problem-solving Tips
HomeworkTry even if you get stuck, move on,
return, etc.
Do not wait until the night before the test.
List quantities asked and all relevant info given to
you.
Draw a picture, schematic, etc. to help you visualize
the problem.
Consider laws, definitions, and equations.
Ask yourself: What are the unique conditions?
Ascertain that the relations you use are appropriate.
There may be intermediate steps in the solution.State l steps and assumptions used.
Make sure you answer all questions asked.
Check the units and conversions.
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Attendance: Attendance is mandatory! Attendance will be taken each class.
A student will be allowed 2 unexcused absences, after which the students
final grade may be dropped by 2.5% for each additional class missed.
Students will be excused without penalty from class because of a religious
observance or matters of health. Come see me if you have missed classes so
that I can help you make up what you missed.
Policy on Calculators: Students will only be allowed to use a simple, four
function calculators on quizzes and exams. Multifunction calculators with
advanced memory capabilities will not be allowed to be used on quizzes or
exams. Students should see the me prior to a quiz or exam if there is any
confusion with this policy.
Policy on Other Electronic Devices:No Electronic Devices during Examsare allowed. The use of mobile phones, pagers, digital music playersman or
any other electronic devices that may disrupt the class are not permitted.
Students are encouraged not to bring these devices to class. If it is necessary
to bring a device to class, it must be turned off or muted.
Other Administrative Matters
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Chapter 1Introduction
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Engineering 101
Performance
CostMaximize!
Minimize as much
as possible!
Maximize as needed!
Dont overdo though
Always a formidable
problem in Engineer ing.
Engineering is the creation of some useful functionality through the use of
human intellect, bound by the laws of Physics, at the lowest possible cost! The concept
of best is chiefly determined by the performance/cost ratio!
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Processing-Structure-Property
Relationships
Properties can varyby orders of
magnitude
Properties strongly
linked to thestructure
Processing can alter
the structure
Understanding thestructure is the key
to mastery of
materials
properties
Properties
Processing Structure
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Multi-scale Hierarchy in Engineering
Materials
Materials are engineered structuresnotblack-boxes!!! Structure has many dimensions.
Atomic bonding..
Missing/extra atoms.
Crystals (ordered atoms)..
Second phase particles..
Crystal texture.
Grain structure
10-6 m
10-8to 10-3 m
Structural control over 7 orders of magnitude on the size-
scale produces what is known as macroscopic properties of
materials.
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Example: Structure-Property Relationships in
Steel
Properties depend on structurehardness vs. structure of steel through
control of quenching rate
Cooling Rate (C/s)
100
200
300
400
500
600
0.01 0.1 1 10 100 1000
(a)
30 mm
(b)
30 mm
(d)
30 mm
(c)
4mm
Brine
llHardness(BHN)
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Example: Control of Electrical Properties
Electrical resistivity of Copper:
T (C)-200 -100 0
1
2
3
4
5
6
Res
istivity(10-8Oh
m
m)
0
Adding impurity
atoms increases resistivity
Deforming Cu increases
resistivity slightly
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Example: Control of Thermal Properties
Space shuttle tiles
Fiber insulation
100 mm
Thermal conductivity of Cu
varies with Zn additions
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Example: Control of Magnetic Properties
Magnetic Storage: Recording medium is
magnetized by recording head
Magnetic Permeability Adding 3% Si in Fe
makes Fe a better
recording medium
Magnetic Field
Ma
gnetization Fe+3%Si
Fe
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Example: Control of Optical Props
Transmittance:Alumina(Al2O3) can be transparent,translucent, or opaque depending on structure, which is
governed by processing.
Single crystal
or polycrystal
with virtually
no porosity and
grain size < 400nanometers.
Polycrystal with
low porosityPolycrystal with
high porosity
Most
Expensive!
More
Expensive!
Cheapest!
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Example: Control of Deterioration
Stress & saltwater cancause cracks
Proper heat treatmentcan slow/eliminate
cracking
Increasing load
C
rackspeed(m/s)
held at
160 C for 1hr
before testing
as-is
10-10
10-8
Alloy 7178 tested insaturated aqueous NaClsolution at 23 C
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The Materials Selection Process
Pick Application Determine required Propertiessuch as mechanical, electrical, thermal, magnetic,optical, etc.
Properties Identify candidate Material(s), itschemical composition and microstructure.
Material Identify the required Processing
Processing (casting, sintering, vapor deposition,joining, annealing, deformation, etc.). governsatomic/crystallographic/microstructural constitution ofthe material as well as its shape!
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Examples: Advanced Materials for
Aerospace Applications
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Example: Micro Electrical Mechanical
Devices (MEMS)
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Example: Environmental Cleanup
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Example: Composites
Used in high
weight/thrust
ratio applications.
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Example: NanoStuff
C60 Buckminsterfullerene
Nanotube
Nanogear
Nanocones
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Example: Bioceramics
Hydroxyapetite Bone Implants
Alumina/HA Hip Replacement
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Summary
Course Goals:
Use the right engineering material for the
application of interest.
Understand the relationship between
processing, properties and structure.
Recognize new design opportunities offered
by materials selection
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Assignment for Lecture 01
Reading:
Chapter 1Chapter 2
There will be no Quiz next
class!