48699 Chapter 1A

Elements of Materials Science and Engineering

ChE 210Instructor: Dr. Ahmed Arafat, PhD

Office: building 45 room 106

E-mail: akhamis@kau.edu.sa

www.kau.edu.sa.akhamis files

Book

Elements of Materials Science and Elements of Materials Science and EngineeringEngineering

Sixth EditionSixth Edition

Lawrence H. van Vlack

ChaptersChapters

Chapter 1: Introduction to Materials Science and EngineeringChapter 2: Atomic Bonding and CoordinationChapter 3: Crystals (atomic order)Chapter 4: Disorder in solid phasesChapter 5: Phase EquilibriaChapter 6: Reaction ratesChapter 7: MicrostructuresChapter 8: Deformation and FractureChapter 9: Shaping Strengthening and Toughening Processes

GradingGrading

• Presence: 1 x 4% = 4 %• Major Exams = 3 x 8% = 24 %• Quizzes: 3 x 4% = 12 %• Laboratory = 20 %• Final Exam= 40 %

Introduction to Materials Science and Engineering

• Materials and civilization• Material and Engineering• Structure properties Performance• Types of materials

Historical PerspectiveHistorical PerspectiveStone → Bronze → Iron → Advanced materials

• Beginning of the Material Science - People began to make tools from stone – Start of the Stone Age about two million years ago.Natural materials: stone, wood, clay, skins, etc.The Stone Age ended about 5000 years ago with introduction of Bronze in the Far East.

• Bronze is an alloy (a metal made up of more than one element), copper + < 25% of tin + other elements.Bronze: can be hammered or cast into a variety of shapes, can be made harder by alloying, corrode only slowly after a surface oxide film forms.

Historical• The Iron Age began about 3000 years ago and

continues today. Use of iron and steel, a stronger and cheaper material changed drastically daily life of a common person.

• Age of Advanced materials: throughout the Iron Age many new types of materials have been introduced (ceramic, semiconductors, polymers, composites…). Understanding of the relationship among structure, properties, processing, and performance of materials. Intelligent design of new materials.

Historicalunderstanding the structure-composition-properties lead to a remarkable progress in properties of materials. e.g. the strength : density ratio of materials, resulted in a variety of new products, from dental materials to tennis racquets.

Materials and Civilization (1)

• Materials are integral part of human culture• In the past: Stone, Bronze and Iron ages

• Role of Engineer: Adapting materials and energy to society’s needs

• The properties of materials depends on the internal structure

• To change the performance of materials, modification of the internal structure is required

Materials and Civilization (2)• Human are able to make things: Objects tools, component

systems

• This require materials to meet these purposes

• Anthropolgists and historians identified the early cultures by the most significant materials used then, e.g. Stone, the Bronze. and the Iron Ages of the past

• These days, are not limited to one predominant material. A lot of sophisticated materials-plastics, silicon, titanium, high-technology ceramics, optical fibers, and so on

• The age of technology.

Materials and Civilization (3)• Improved materials improved products• E.g. clothes, tools, homes, weapons and

vehicles• Closer to modern ages British and Americans

made the rail road systems which have lead to severe socioeconomic progress

• However, without the invention of Kelly and Bessemer in steel production, the rail road systems could not open the west of US and to develop the industry in UK

Materials and Engineering (1)

• Engineer, design products and systems and monitor their use

• Every product is made of materials and energy is involved in production and in use.

• This is why all Engineers have to study materials science during their undergraduate study

Materials and Engineering (3)• More example: Superconductor circuit• Normally made from ceramics at +78K very brittle at

these temperatures.• A developed process to shape these materials into wires

processing will be limited to plasma spraying and similar techniques

Structure

LengthLength--scalesscales

Angstrom = 1Å = 1/10,000,000,000 meter = 10-10 mNanometer = 10 nm = 1/1,000,000,000 meter = 10-9 mMicrometer = 1µm = 1/1,000,000 meter = 10-6 mMillimeter = 1mm = 1/1,000 meter = 10-3 m

• Interatomic distance ~ a few Å• A human hair is ~ 50 µm• Elongated bumps that make up the data track on CD

are ~ 0.5 µm wide, minimum 0.83 µm long, and 125 nm high

Properties

Types of MaterialsTypes of MaterialsMetals: valence electrons are free moving, and spread in an

'electron sea' that "glues" the ions together. Strong, ductile, conduct electricity and heat well, are shiny if polished.

Semiconductors: the bonding is covalent. Their electrical properties depend strongly on minute proportions of contaminants. Examples: Si, Ge, GaAs.

Ceramics: composed of ions, and are bound by Coulomb forces. They are usually combinations of metals or semiconductors with oxygen, nitrogen or carbon, Hard, brittle, insulators. Examples: glass, porcelain.

Polymers: are bound are covalent bonded or weak van der Waals bonded, based on C and H. They decompose at moderate temperatures (100 – 400oC), and are lightweight. Examples: plastics rubber.