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Lecture Objectives

Understand the procedural requirements of this course.

Understand where this body of knowledgefits in the skill set needed for and engineer Have a general sense of the role materials

have played in technological developmentand their role as limiting technologies.

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Course Objectives

Key concepts to help you organize this areaof knowledge

Tools to help in material selection for design.Learn language and concepts so you can

deal with Materials ProfessionalsDevelop general skills necessary for professional success.

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Grade Components

Course grade 75% Lecture/ 25% Lab

Lecture Grade – 30% Midterms – 30% Final Exam

– 20% Homework – 20% Quizzes

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Keys to Success

Do the HomeworkDon’t miss class & don’t be late

Turn in everything required in labLearn from the lecture objectivesMake sure you can do the kinds of problems

specified.DON’T MEMORIZE – UNDERSTAND!

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Special Engineering Skills

Tools of ApproximationThe sanity Check – the

“Engineering Sense” Units, Units, UnitsPrecision and Accuracy

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Classes of Materials

A. Metals

B. Ceramics

C. Polymers

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Fourth Class of MaterialsComposites

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Materials History: Stone Age

Earliest materials: – stone (ceramic) – wood (natural

composite)

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Materials History: Bronze Age

Copper Alloy (Cu andSn), Adobe (ceramiccomposite)

Bronze agecivilizations in Europe,

Asia, and the Americas

Greece (bronze)conquered by Rome(Iron)

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Materials History: Iron Age

Iron harder & stronger than bronzeIron civilizationsgenerally conqueredbronze based cultures

British Iron Age sword &shield (200-300 BC)

Thebritishmuseum.ac.uk

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Materials History: Age of Steel

From around 1800 tomid 1900’s Steel is a controlledalloy of iron andcarbon

Eades Bridge – StLouis, Missouri

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Mid 1900’s to 1980’s: Age of Engineering Materials

Large variety of materials available – polymers, metal alloys, composites,ceramicsNo single material dominantDetailed characterizations available for precise and reliable use

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1980-? The Age of EngineeredMaterials

Rapid expansion of biological materials,tissue engineering, advanced composites,toughened ceramics, superalloysMaterials designed to requirements of theproduct engineer Concurrent engineering required

THE MATERIAL AND THE PRODUCT AREDESIGNED TOGETHER

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The Place of Materials inManufacturing Engineering

Material

PeopleProcess

Product

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The Place of Materials inMechanical Engineering

CONCEPT

ANALYSIS

MATERIALS

PRODUCT

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Terms & Concepts: Force

“Push or pull of one object on another.”

Five forces in the universe-Electric-Magnetic

-Strong-Weak -Gravitational

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Application

What force is holding you up against the pull

of gravity as you sit in your seat?

a. Normal force c. Strong force

b. Magnetic force d. Electrical force

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Terms & Concepts: Temperature

Temperature is a measure of the averagespeed of molecules in a piece of matter.

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The speed of particles is distributed accordingto a Maxwell distribution

Temperature

Fraction

Of

Atoms

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The root mean squared (rms) velocity can beestimated from:

VRMS = 3kT/m

where k – Boltzman’s constant,T- temperature in K, m – mass of particles

Temperature

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Temperature

Absolute scale: Kelvin At 0K there is no Kinetic Energy

K = C + 273

HINT: If you always use K in the class, you

will never be wrong due to a temperatureinput.

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Application Question

CO 2 leaves a closed plastic soda bottlethrough a process called diffusion. Themolecules squeeze between the polymer molecules. If the temperature of a storagewarehouse is increased will the soda lose itfizz?a. Faster b. Slower c. No change

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Terms & Concepts: Pressure

Caused by the collision of molecules

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Crude estimate of number of collisions per unit area (flux)

= nvwhere n-number of molecules per unitvolume, v-most probable velocity fromdistribution

Pressure

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Application QuestionFormation of polyethylenepolymer requires that

molecules in a gascollide with each other and react (combine) tomake long chains.Higher temperatures willresult in more collisionswhich increase the

production rate.

A. True B. False https://reader009.{domain}/reader009/html5/0428/5ae45bff533a0/5ae45c0d136

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Pressure in Solids

In a solid – pressure is called stress.Stress is the amount of force per unit area

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First Universal Principle

“All systems seek the lowest possible freeenergy state ”

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First Universal Principle

“All systems seek the lowest possible freeenergy state ”

-Water flows downhill – reduces PE

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First Universal Principle

“All systems seek the lowest possible freeenergy state ”

-Water flows downhill – reduces PE-Electrons drop to lowest energy level

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First Universal Principle

“All systems seek the lowest possible freeenergy state ”

-Water flows downhill – reduces PE-Electrons drop to lowest energy level-Water forms spherical droplets – surfaceenergy minimization

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First Universal Principle

“All systems seek the lowest possible freeenergy state ”

-Water flows downhill – reduces PE-Electrons drop to lowest energy level-Water forms spherical droplets – surfaceenergy minimization

-Hot things “cool off” by giving away KE

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First Universal Principle

“All systems seek the lowest possible freeenergy state ”

-Water flows downhill – reduces PE-Electrons drop to lowest energy level-Water forms spherical droplets – surfaceenergy minimization

-Hot things “cool off” by giving away KE -The entire universe is winding down

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Comprehension Self-Test

1. Temperature is the measure of the average ______ of molecules in a piece of matter.

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Comprehension Self-Test

1. Temperature is the measure of the average speed of molecules in a piece of matter.

2. The five forces in the universe are electric,magnetic, strong, weak, and ______.

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Comprehension Self-Test

1. Temperature is the measure of the average ______of molecules in a piece of matter.a. number b. size c. speed d. charge

2. The force by which the chair is holding you up isa. magnetic b. gravitational c. strong d. electric

3. In the measurement of V RMS , velocity increases asthe square root of the _____.

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Comprehension Self-Test

1. Temperature is the measure of the average speed of molecules in a piece of matter.

2. The five forces in the universe are electric,magnetic, strong, weak, and gravitational.

3. In the measurement of V RMS , velocity increases asthe square root of temperature.