MATERIAL SCIENCE (SDD 12302)

INTRODUCTION TO MATERIAL INTRODUCTION TO MATERIAL SCIENCE & ENGINEERINGSCIENCE & ENGINEERING

OBJECTIVESAfter learning this topic, student will be able:1. List six different property classifications of materials that determine their

applicability.2. Cite the four components that are involved in the design, production and

utilization of materials and briefly describe the interrelationships between these components.

3. Cite three criteria that are important in the materials selection process.4. (a) List the three primary classifications of solid materials and then cite the distinctive chemical feature of each.

(b) Note the two types of advanced materials and for each, its distinctive feature(s).5. (a) Briefly define “smart material/system.”

(b) Briefly explain the concept of “nanotechnology” as it applies to materials.

INTRODUCTION• Material :

substance of which something is composed or made.

INTRODUCTION• Material Science :

A scientific discipline which is primarily concerned with the search for basic knowledge about internal structure, properties and processing materials.

Investigating relationships that exist between the structure and properties of materials

INTRODUCTION• Material Engineering :

An engineering discipline which is concerned with the use of fundamental and applied knowledge of materials so that they can be converted into products needed or desired by society.

Is, on the basis of these structure-property correlation, designing or engineering the structure of a material to produce a pre-determined set of properties

INTRODUCTION

Basic knowledge of materials

Applied knowledge of materials

Resultant knowledge of the structure, properties,

processing and performance of engineering materials

Material EngineeringMaterial Science

Material Science and Engineering

Structure of materials:

• the arrangement of its internal components. • subatomic structure involves electrons within the

individual atoms and interaction with their nuclei. • on atomic level, structure encompasses the organization

of atoms or molecules relative to one another.

INTRODUCTION

• A property is a material trait in terms of the kind and magnitude of response to a specific imposed stimulus.

• definitions of properties are made independent of material shape and size.

Properties of materials:

Properties of solid materials may be grouped into six different categories: mechanical, electrical, thermal, magnetic, optical and deteriorative.

(i) Mechanical properties relate deformation to an applied load or force. Examples include elastic modulus and strength.

(ii) Electrical properties, such as electrical conductivity and dielectric constant, the stimulus are an electric field.

(iii) Thermal properties can be represented in terms of heat capacity and thermal conductivity.(iv) Magnetic properties demonstrate the response of a material to the application of a magnetic field.(v) Optical properties, such as index of refraction, the stimulus is electromagnetic and light radiation.(vi) Deteriorative characteristics relate to the chemical reactivity of material

INTRODUCTIONThe four components of the discipline of materials science and engineering and their linear interrelationship.

Processing Structure Properties Performance

MATERIAL SELECTION3 criteria on which the final decision is normally based:(i) dictate the properties required of the

material(ii) consider of any deterioration of material

properties that may occur during service operation

(iii) economics

Why study materials science & engineering?• To be able to select a material for a given

use based on considerations of cost and performance.

• To understand the limits of materials and the change of their properties with use.

• To be able to create a new material that will have some desirable properties

TYPE OF ENGINEERING MATERIALS

Engineering Materials

Metals Polymers Ceramics Composites

METALS

METALS• combinations of metallic elements • some properties:

– good electrical– thermal conductivity– high strength– high stiffness– ductile

• metals and alloys are commonly divided into two classes:– Ferrous metals and alloys

• contain large percentage of iron • examples: steels and cast irons

– Nonferrous metals and alloys• do not contain iron or only a relatively small amount of iron• examples: aluminum (Al), copper (Cu), zinc (Zn), titanium (Tn) and nickel (Ni)

METALSTwo categories:

1. Pure metalselements which come from a particular are of the periodic table. Ex: iron, copper and aluminum

2. Metal alloyscontain more than one metallic element. Their properties can be changed by changing the elements present in the alloy. Ex: stainless steel, nickel, chromium.

POLYMERS

POLYMERS• has a repeating structure in large chainlike molecules - based

on a carbon backbone. • based on carbon, hydrogen and other nonmetallic elements• some properties:

– low densities– thermal and electrical insulators– do not have high strengths– flexible– lightweight– corrosion resistant– easy to process at low temperatures– generally inexpensive

POLYMER

PLASTICS ELASTOMERS

THERMOPLASTICS THERMOSETS

• Some applications of thermoplastics:– electrical wire insulation– bottles– toys– pens

• Some applications of thermosets:– melamine (plate)– electrical plugs and switches – saucepan handles

• Some applications of elastomer– automobile tires– natural rubber

CERAMICS

CERAMICS• inorganic materials (metallic & nonmetallic elements)• oxides, nitrides, and carbides• crystalline, non-crystalline or a mixture of both• Properties at RT:

High melting pointHigh chemical stabilitiesHigh hardnessHigh temperature strengthBrittle (lack ductility)Poor electrical & thermal conductorResistance to corrosion

Special properties of some ceramics• are magnetic materials• are piezoelectric materials• are superconductors at very low temperatures.

Industrial Importance of Ceramics• pottery and other artwork. • silicon, a semiconductor but also a ceramic

material, has been the material which has made computers possible.

• ceramic fibers such as graphite and aluminum oxide with their extremely high stiffness have led to the production of fiber-reinforced composites.

COMPOSITES

COMPOSITES• combination of two or more materials • a matrix phase + a reinforcing phase• Designed to ensure a combination of the best properties

of each componentmaterial

• Examples includepolymer/ceramic and metal/ceramic composites.

Advantages of composites:• High strength to weight ratio (low density

high tensile strength)• High creep resistance• High tensile strength at elevated temperatures• High toughness

Types of composite:Particle-reinforced composites: • Particles used for reinforcing include

ceramics and glasses such as small mineral particles, metal particles such as aluminum, and amorphous materials, including polymers and carbon black.

• An example of particle reinforced composites is an automobile tire which has carbon black particles in a matrix of polyisobutylene elastomeric polymer

• Reinforcing fibers can be made of metals, ceramics, glasses, or polymers thathave been turned into graphite & known as carbon fibers.

• Fibers are difficult to process into composites, making fiber-reinforced composites relatively expensive.

• Used in sports equipment, such as a time-trial racing bicycle frame which consists of carbon fibers in a thermoset polymer matrix.

• Body parts of race cars and some automobiles are composites made of glass fibers (or fiberglass) in a thermoset matrix.

Fiber-reinforced composites

• composed of two-dimensional sheets or panels that have a preferred high strength direction such as is found in wood and continuous and aligned fiber-reinforced plastics.

• One example of a relatively complex structure is modern ski and another example is plywood.

Laminar

Sandwich Panels:

• Consist of two strong outer sheets which are called face sheets and may be made of aluminum alloys, fiber reinforced plastics, titanium alloys, steel.

• Sandwich panels can be used in variety of applications which include roofs, floors, walls of buildings and in aircraft, for wings, fuselage and tailplane skins

ADVANCED MATERIALADVANCED MATERIALS

SEMICONDUCTOR BIOMATERIALS MATERIALOF

THE FUTURE

SMARTMATERIAL

NANOENGINEEREDMATERIAL

• That are utilized in high-technology applications.– Example: electronics equipment such as VCRs, DVD

players, Military rockets, Liquid Crystal Display• Mean a device or product that operates or

functions using relatively intricate and sophisticated principles.

• They maybe of all materials types and expensive

SEMICONDUCTORS

SEMICONDUCTORS• Electrical properties that are intermediate

between the electrical conductors and insulators. • The electrical characteristic of these materials are

extremely sensitive to the presence of minute concentrations of impurity atoms.

• Conductivity increasing with temperature

BIOMATERIALS

BIOMATERIALS• Components implanted into the human body for

replacement of diseased or damaged body parts. • Must not produce toxic substances and must be

compatible with body tissues. • All of above materials – metals, ceramics, polymers,

composites and semiconductors – may be used as biomaterials.

• For example, some of the biomaterials that are utilized in artificial hip replacements.

MATERIAL OF THE FUTURE• Smart Materials

– A group of new and state-of-the-art materials now being developed that will have a significant influence on many of our technologies.

– Components are include some type of sensor and a actuator

MATERIAL OF THE FUTURE• Nanoengineered materials

– dimension <100 nm (~500 atom diameters)– to understand the chemistry & physics of

materials has been to begin by studying large and complex structures.

– to investigate the fundamental building of these blocks of these structures.

– Ex: carbon nanotube

MODERN MATERIALS’ NEEDS• Engine efficiency increases at high temperatures: requires high

temperature structural materials.• Use of nuclear energy requires solving problem with residues, or

advances in nuclear waste processing.• Hypersonic flight requires materials that are light, strong and resist

high temperatures.• Optical communications require optical fibers that absorb light

negligibly.• Civil construction – materials for unbreakable windows.• Structures: materials that are strong like metals and resist corrosion

like plastics

THANK YOU…..