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CHEN 313: Materials Science and Engineering. Course Objective. Introduce fundamental concepts in Materials S&T. You will learn about:. • material structure. • how structure dictates properties. • how processing can change structure. This course will help you to:.

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chen 313 materials science and engineering
CHEN 313: Materials Science and Engineering

Course Objective...

Introduce fundamental concepts in Materials S&T

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

Class Notes adapted/prepared by Jorge Seminario (TAMU)

a

required text
Required text

Fundamentals of Materials Science and Engineering:

An Integrated Approach

3rd Edition

W.D. Callister, Jr. and D. G. Rethwisch

John Wiley and Sons, Inc. (2007).

Both book and accompanying CD-ROM are useful.

f

grading
GRADING

Homework, quizzes, (INDIVIDUAL)15%

Special assignments (GROUPS) 10%

exam # 1 15%

exam #2 15%

exam #3 15%

final 30%

g

slide4

Special Assignment

Check 2010-2011 Issues of Nature & Science; find the best topic you like

Propose and justify a topic February 7

Instructor will decide topics on Feb 11

First Draft due on February 28

Second Draft due on March 21

Final version due on April 22

1 1 historical perspective
1.1 Historical Perspective
  • Early Civilivations
    • Bronze Age, Iron Age, Stone Age
    • Materials were naturally occuring
historical perspective cont d
Historical Perspective (Cont’d)
  • Modern Era
    • Understand structure and properties
    • New materials have evolved
      • Ex. Plastics, Glasses, Fibers
1 2 materials science and engineering
1.2 Materials Science and Engineering
  • Structure
    • Atomistic – Atoms, small molecules ~ 1 Å
    • Nanoscopic – molecules, clusters, ~1 nm
    • Microscopic – Large groups of atoms agglomerated
    • Macroscopic – can be viewed by the “naked eye”
1 3 why do we study materials
1.3 Why do we study materials?

Many engineering fields deal with a design problem involving materials sooner or later

For example: transmission gears, superstructure of a building, oil refinery component, electronics, medicine, etc.

However, the problem is selecting the right material from the thousands out there.

material criteria
Material criteria
  • Many selecting criteria affect final decision:
    • In-service conditions
    • Deterioration
    • Finished product cost
in service conditions
In-service conditions

dictates the material required properties

Rarely a material possess the maximum or ideal combination of properties

Sacrificing one characteristic for another might be necessary

i.e., strength vs. ductility: the stronger a material the less ductile (malleable)

deterioration
Deterioration
  • Can occur during service operation
  • Mechanical strength might be lowered by:
    • Exposure to elevated temperatures
    • Exposure to corrosive environments

http://majarimagazine.com/2009/01/corrosion-in-material-of-construction/

finished product cost
Finished product cost

You could have perfect material, but too costly

Again, some compromise or sacrifice must be made

Cost of finished piece includes fabrication cost

materials criteria
Materials Criteria

As an engineer, must familiarize yourself with these criteria

Also be comfortable with processing techniques

In conclusion, the more proficient, the more confident you will be in making judgment based on these criteria

slide18

Three Basic Material Classes

  • Metals
  • Ceramics
  • Polymers
  • Classifications are based on:
    • Chemical Makeup
    • Atomic Structure
  • Additional Material Classes:
    • Composites
    • Advanced Materials
metals
Metals
  • Composed primarily of metallic elements
    • Possible nonmetallic species present
    • Orderly atomic arrangement
    • High density
    • High mechanical strength
      • Very Stiff & Strong
      • High Ductility
      • High Fracture Resistance
    • High electrical & thermal conductivity
    • Typically magnetic
ceramics
Ceramics
  • Compounds of metallic and nonmetallic elements
    • Commonly oxides, nitrides & carbides
    • Mechanical strength comparable to metals
      • High stiffness & strength
      • Extremely low ductility
      • High fracture susceptibility
    • Low electrical & thermal conductivity
    • Optically variant
      • May be transparent, translucent or opaque
    • Some ceramics may be magnetic
ceramic membrane ultrafiltration
Ceramic membrane: Ultrafiltration

Ceramic membrane filter is widely used for filtration in industrial areas of food , beverage, pharmaceutical, chemical, petrochemical and environment-protecting

Ceramic Membrane Elements

polymers
Polymers
  • Organic plastic & rubber compounds
    • Large molecular structures based on hydrocarbon chains
    • Frequent presence of oxygen, nitrogen and silicon
    • Low density
    • Unique mechanical properties
      • Lower stiffness & strength compared to metals & ceramics
      • Extremely high ductility & pliability
    • High degree of chemical inertness
      • Unreactive in a large range of environments
      • May decompose at temperature
    • Low electrical and thermal conductivity
    • Nonmetallic
shape memory polymer
shape-memory polymer

clinical applications

Xu J , Song J PNAS 2010;107:7652-7657

composites
Composites
  • A material composed of materials from two or more classes
    • Engineered to achieve a combination of properties not present in one single material
    • Fiberglass is a classic example of a composite material
      • Glass fibers are embedded within an epoxy or polyester substrate
      • Glass fibers cause the material to be strong & stiff
      • Polymer base provides ductility & flexible
    • Carbon Fiber Reinforced Polymers (CFRP) are a second example of composite materials
      • Carbon fibers are embedded in a polymer base
      • Stronger & stiffer than fiberglass, but far more expensive
1 5 advanced materials

1.5 Advanced Materials

Advanced materials include: semiconductors, biomaterials, ‘materials of the future,’ which include materials used in lasers, integrated circuits, magnetic storage, LCD’s, and fiber optics.

Advanced materials are typically utilized in high-tech applications and are typically traditional materials whose properties have been enhanced as well as newly developed, high performance materials.

semiconductors
Semiconductors

Semiconductors have electrical properties that are intermediate between the electrical conductors (metals and alloys) and insulators (ceramics and polymers).

The electrical characteristics of these materials are extremely sensitive to the presence of minute concentrations of impurity atoms which may be controlled over very small regions.

Semiconductors have made possible the advent of integrated circuitry that has revolutionized electronics and the computer industry.

biomaterials
Biomaterials

Biomaterials are employed in components implanted into the human body for replacement of diseased/damaged body parts

These materials must not produce toxic substances and must be compatible with body tissues.

Metals, ceramics, polymers, composites, and semiconductors may all be used as bio materials.

smart materials
Smart Materials

Smart materials are new, state-of-the-art materials for new technologies.

The “smart” implies that these materials are able to sense changes in their environments and then respond to these changes in predetermined manners.

Components of a smart material include a type of sensor (that detects input) and an actuator (that performs a responsive and adaptive function).

four common smart materials
Four common Smart Materials:
  • Magnetostrictive – similar to piezoelectric except for magnetic fields.
  • Electrorheological fluids – liquids that experience dramatic changes in viscosity upon application of electric fields. Magnetorheological fluids also exist.

Shape-memory – metals that, after being deformed, revert back to their original shape with a temperature change.

Piezoelectric ceramics – expand and contract in response to applied electric fields. They also generate an electric field when deformed.

nanoengineered materials
Nanoengineered Materials

The ability to carefully arrange atoms from the bottom up allows for the opportunity to develop mechanical, electrical, magnetic, and other properties into materials that are otherwise not possible.

The ‘Nano’ prefix denotes that the dimensions of these entities is on the order of a nanometer, or 10-9 meters.

This is the inside of a carbon nanotube.

1 6 modern materials needs
1.6 Modern materials’ needs

Although nuclear energy is promising, reliance on materials will continue

From fuels, to containment structures, to facilities where radioactive waste is disposed

Transportation requires a lot of energy

Materials of high strength low density will reduce weight and enhance machine efficiency

http://energymats.lboro.ac.uk/

modern materials needs
Modern materials’ needs

Economical sources of energy are in need

Materials will have significant role in this

i.e. solar cells = convert solar energy into electrical energy but materials are expensive

These must be replaced with high efficient, low cost materials

http://www.solarnavigator.net/solar_panels.htm

modern materials needs1
Modern materials’ needs

Hydrogen fuel cell very feasible and attractive

Holds promise in the car industry as a power source

However, before this is made efficient, better materials must be engineered

modern materials needs2
Modern materials’ needs

Producing new materials is great, but must be observed carefully

New materials could be great, but the pollution or waste produced during process needs to be considered

Also, less pollution and spoilage due to less mining of raw materials.

modern materials needs3
Modern materials’ needs
  • Many materials used are from non-renewable sources
  • i.e. oil and some metals
  • Materials are being depleted steadily which is cause for:
    • Need of discovery of additional reserves
    • Development of similar materials with less adverse environmental impact
    • Increase recycling efforts
modern materials needs4
Modern materials’ needs
  • Challenges still remain even though large technological advances have been made
  • For example, the development of even more sophisticated and specialized materials
  • Also the environmental impact of material production
  • In conclusion, development is only good if all factors are considered
  • Best judgment made based on factors
the materials selection process
The Materials Selection Process

1.

Pick Application

Determine required Properties

Properties: mechanical, electrical, thermal,

magnetic, optical, deteriorative.

2.

Properties

Identify candidate Material(s)

Material: structure, composition.

3.

Material

Identify required Processing

Processing: changes structure and overall shape

ex: casting, sintering, vapor deposition, doping

forming, joining, annealing.

3

summary
SUMMARY

Course Goals:

• Use the right material for the job.

• Understand the relation between properties,

structure, and processing.

• Recognize new design opportunities offered

by materials selection.

9