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Chapter 1-
CHEN 313: Chemical Engineering Materials
Course Objective...Introduce fundamental concepts in Chem. Eng. Materials
You will learn about:• material structure• how structure dictates properties• how processing can change structure
This course will help you to:• use materials properly• realize new design opportunities
with materials
a
Chapter 1-
Lecturer: Dr. Perla B. Balbuena
Time: MWF 1:50-2:40 pm
Location: CHEN 102
Activities:• Present new material• Announce reading and homework• Take exams*
*Make-ups given only for emergencies.*Discuss potential conflicts beforehand.
b
LECTURES
Chapter 1-
Teaching Assistant will
• grade your homework
NameDiego Cristancho
Office____ JEB
Tel.X-XXXX
d
TEACHING ASSISTANTS
Chapter 1-
Activities:• Discuss homework, exams• Discuss lectures, book
After class each Wednesday**
**Contact Dr Balbuena by e-mail for other times
e
OFFICE HOURS
Chapter 1-
• other books
Required text:• Fundamentals of Materials Science and Engineering: An Integrated Approach 2nd Edition
W.D. Callister, Jr., John Wiley and Sons, Inc. (2005). Both book and accompanying CD-ROM are useful.
Other Materials:• papers
f
COURSE MATERIAL
Chapter 1-
Midterm # 1 16.67 %
Midterm #2 16.67%Tentatively scheduled for: 3/19, 7-9 pm
Midterm #3 16.67%Tentatively scheduled for: 4/16, 7-9 pm
Final 25%Scheduled for: 5/8, 3:30-5:30 pm
g
GRADING
Tentatively scheduled for:2/12, 7-9 pm
Homework, class participation: 10%Projects 15 %
Chapter 1-
KEEP TO THE READING /HOMEWORK CYCLE
MON TUE
class
WED THU FRI
Hmk is assignedHmk is due
h
THE WEEKLY “CYCLE”
classclass
Chapter 1-
Materials are... engineered structures...not blackboxes!
Structure...has many dimensions...
Structural feature Dimension (m)
atomic bonding
missing/extra atoms
crystals (ordered atoms)
second phase particles
crystal texturing
< 10-10
10-10
10-8-10-1
10-8-10-4
> 10-6
1
CHAPTER 1: MATERIALS SCIENCE & ENGINEERING
Chapter 1-
Introduction
• Materials Science. Investigation of the relationships between the structures and properties of materials– How do the arrangement of a materials components (e.g.
atoms, etc.) influence its properties (e.g. does it conduct electrons or not)?
• Materials Engineering. Designing the structure of a material so that it has desired properties. The design is based on the structure-property relationships derived by the Materials Scientist
Chapter 1-
Introduction
• Another view of this course:– Macroscopic versus microscopic
• Engineers typically are interested in macroscopic properties (e.g. heat capacities, viscosity, fracture strength, etc.)
• Scientists often describe things in microscopic terms (e.g. bond strength, orbital theory, etc.)
• However, recent trends tend to mix both approaches: Engineers and Scientists both look at micro and macroscopic properties and try to understand the connection between them
– In this class I am going to, whenever possible, show the interrelationship between microscopic and macroscopic properties
Chapter 1-
Introduction
• Processing/Structure/Properties/Performance– They are interrelated!
Processing Structure Properties Performance
Figure 1.1
• As engineers you are probably more tuned into processing and performance• However, how processing influences the structure is critical• Why? This will influence the material properties, which of
course affect its performance!
Chapter 1-
Introduction
• What do I mean by structure?– Structure is related to the arrangement of a material’s
components• This could be on any length scale• Atomic, nano-, micro-, macro-
– All of these length scales matter!
Types of Carbon (just plain old carbon!)
Diamond Graphite C60 - Fullerene Carbon nanotubes
Chapter 1-
Introduction
• Properties– How the material behaves in terms of the kind and
magnitude of response to an imposed stimulus– What are the stimuli?
• Temperature• Magnetic field• Electric field
– Important point: material properties are typically defined independent of material shape and size!
• Why?
– However… what about nanosize objects?
Chapter 1-
Introduction
• Properties– For the purposes of this course we will group properties into six
categories• Mechanical
• Electrical
• Thermal
• Magnetic
• Optical
• Deteriorative
Chapter 1-
Introduction
Property Example (Physics) Example Properties
Mechanical Rate of material deformation to an applied load
Elastic modulus
Electrical Response of material to an applied electrical field
Electrical conductivity
Thermal Material expansion/contraction with change in temperature
Heat capacity, thermal
conductivity
Magnetic Response of a material to an applied magnetic field
Magnetic susceptibility
Optical Response of material to electromagnetic radiation
Refractive index
Deteriorative Rate of decomposition of material (often in presence of acid, etc.)
Corrosion rate
Chapter 1-
Introduction
• Processing Structure Properties
Same material – aluminum oxide. Depending on structure (which is influenced by processing) materials are transparent, translucent, opaque
Chapter 1-
Introduction
• Classification of Materials– In materials science there have typically been three
categories of materials• Metals• Ceramics• Polymers
– I will also use this convention; in addition there are several others that are variants (or combinations) of the three
• Composites• Semiconductors• Biomaterials
Chapter 1-
Introduction
• Metals– Defining characteristic of a metal
• High number of delocalized electrons– What does this mean? -- The electrons (outer valence e-’s of
the various atoms) are not bound to particular atoms
– Impact delocalization has on properties? Metals are:
» Good conductors of heat and electricity
» Not transparent to visible light
» Mechanically they are strong, yet deformable
• Examples – silver, gold, platinum, copper
Chapter 1-
Chapter 1-
Introduction
• Ceramics– “Between” metallic and nonmetallic compounds
• Oxides, nitrides, and carbides• These materials are typically insulators of heat and electricity• More resistant to high temperature (e.g. high melting points)
and harsh environments (e.g. pH) than metals• Mechanically – ceramics are hard but brittle
• Examples: silica (glass), alumina, silicon nitride
Chapter 1-
Introduction
• Polymers– Plastics and rubber materials
• Macromolecules – generally formed from carbon, nitrogen, and hydrogen (there are polymers that contain metals)
• Usually have low densities• Can be extremely flexible• Not stable at high temperatures typically
• Examples: polyethylene, polystyrene, polyamide (Nylon®)
*CH2
H2C
*n
*CH
H2C
*n
*
HN
R
HN R'
O
*
O
n
Chapter 1-
Introduction
• Composites– Exactly what it sounds like: a new material that
consists of more than one component• Fiberglass – glass fibers embedded in a polymeric matrix• Idea – get desirable features of each material component• Complicated though – does not always work out as well as
you’d like
Chapter 1-
Introduction
• Semiconductors– Materials with electrical properties intermediate of a
metal (good conductor) and a ceramic (good insulator)– Silicon is the essential example – computer chips
• Key to use of semiconductors is the extremely precise control of dopant atoms that are used to manipulate the conducting properties
Chapter 1-
Introduction
• Biomaterials– Use of the above materials in life science applications– Key point: the material must not lead to an adverse
physiological reaction– Hip implants are the big success story here
Chapter 1-
ex: hardness vs structure of steel • Properties depend on structure
Data obtained from Figs. 10.21(a)and 10.23 with 4wt%C composition,and from Fig. 11.13 and associateddiscussion, Callister 6e.Micrographs adapted from (a) Fig.10.10; (b) Fig. 9.27;(c) Fig. 10.24;and (d) Fig. 10.12, Callister 6e.
ex: structure vs cooling rate of steel • Processing can change structure
2
Structure, Processing, & Properties
Cooling Rate (C/s)
100
200
300
400
500
600
0.01 0.1 1 10 100 1000
(a)
30m
(b)
30m
(d)
30m(c)
4m
Hard
ness
(B
HN
)
Chapter 1-
1. Pick Application Determine required Properties
2. Properties Identify candidate Material(s)
3. Material Identify required Processing
Processing: changes structure and overall shapeex: casting, sintering, vapor deposition, doping forming, joining, annealing.
Properties: mechanical, electrical, thermal,magnetic, optical, deteriorative.
Material: structure, composition.
3
The Materials Selection Process
Chapter 1-
T (°C)-200 -100 0
Cu + 3.32 at%Ni
Cu + 2.16 at%Ni
deformed Cu + 1.12 at%Ni
1
2
3
4
5
6
Resi
stiv
ity,
(1
0-8 O
hm
-m)
0
Cu + 1.12 at%Ni
“Pure” Cu
• Electrical Resistivity of Copper:
• Adding “impurity” atoms to Cu increases resistivity.• Deforming Cu increases resistivity.
4
Adapted from Fig. 18.8, Callister 6e.(Fig. 18.8 adapted from: J.O. Linde,Ann Physik 5, 219 (1932); andC.A. Wert and R.M. Thomson,Physics of Solids, 2nd edition,McGraw-Hill Company, New York,1970.)
ELECTRICAL
Chapter 1-
• Space Shuttle Tiles: --Silica fiber insulation offers low heat conduction.
• Thermal Conductivity of Copper: --It decreases when you add zinc!
Composition (wt%Zinc)Therm
al C
onduct
ivit
y
(W/m
-K)
400
300
200
100
00 10 20 30 40
5
Fig. 19.0, Callister 6e.(Courtesy of LockheedMissiles and SpaceCompany, Inc.)
100m
Adapted fromFig. 19.4W, Callister 6e. (Courtesy of Lockheed Aerospace Ceramics Systems, Sunnyvale, CA)(Note: "W" denotes fig. is on CD-ROM.)
Adapted from Fig. 19.4, Callister 6e.(Fig. 19.4 is adapted from Metals Handbook: Properties and Selection: Nonferrous alloys and Pure Metals, Vol. 2, 9th ed., H. Baker, (Managing Editor), American Society for Metals, 1979, p. 315.)
THERMAL
Chapter 1-
• Magnetic Permeability vs. Composition: --Adding 3 atomic % Si makes Fe a better recording medium!
Magnetic FieldMagneti
zati
on
Fe+3%Si
Fe
Adapted from C.R. Barrett, W.D. Nix, andA.S. Tetelman, The Principles ofEngineering Materials, Fig. 1-7(a), p. 9,1973.Electronically reproducedby permission of Pearson Education, Inc.,Upper Saddle River, New Jersey.
6
Fig. 20.18, Callister 6e.(Fig. 20.18 is from J.U. Lemke, MRS Bulletin,Vol. XV, No. 3, p. 31, 1990.)
• Magnetic Storage: --Recording medium is magnetized by recording head.
MAGNETIC
Chapter 1-
• Transmittance: --Aluminum oxide may be transparent, translucent, or opaque depending on the material structure.
7
Adapted from Fig. 1.2,Callister 6e.(Specimen preparation,P.A. Lessing; photo by J. Telford.)
single crystalpolycrystal:low porosity
polycrystal:high porosity
OPTICAL
Chapter 1-
• Stress & Saltwater... --causes cracks!
• Heat treatment: slows crack speed in salt water!
4m--material: 7150-T651 Al "alloy" (Zn,Cu,Mg,Zr)
Adapted from Fig. 11.20(b), R.W. Hertzberg, "Deformation and Fracture Mechanics of Engineering Materials" (4th ed.), p. 505, John Wiley and Sons, 1996. (Original source: Markus O. Speidel, Brown Boveri Co.)
8
Adapted from Fig. 17.0, Callister 6e.(Fig. 17.0 is from Marine Corrosion, Causes, and Prevention, John Wiley and Sons, Inc., 1975.)
Adapted from Fig. 11.24,Callister 6e. (Fig. 11.24 provided courtesy of G.H.Narayanan and A.G. Miller, Boeing CommercialAirplane Company.)
“held at 160C for 1hr before testing”
increasing loadcrack
sp
eed
(m
/s)
“as-is”
10-10
10-8
Alloy 7178 tested in saturated aqueous NaCl solution at 23C
DETERIORATIVE
Chapter 1-
• Use the right material for the job.
• Understand the relation between properties, structure, and processing.
• Recognize new design opportunities offered by materials selection.
Course Goals:
9
SUMMARY
Chapter 1-
Reading: Chapter 1. Class notes are in:http://che.tamu.edu/people/faculty/
Click on Balbuena, then on Research Page, then on Teaching: 313 Materials
HW # 1: due Friday, January 26: Problems 2.2, 2.3, 2.4, 2.5, 2.8, 2.13, 2.15, 2.18, 2.22, and 2.12
0
ANNOUNCEMENTS
