Mechanical Properties of Materials Lecture 01

7/25/2019 Mechanical Properties of Materials Lecture 01

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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!

Mechanical Properties of Materials Lecture 01

Documents

Transcript of Mechanical Properties of Materials Lecture 01