Manufacturing Technology - lecture-notes.tiu.edu.iq

Unit 2 Lesson 4

Manufacturing Technology

Instructor: Dr. Dlair O. Ramadan

TOPIC: Properties of Materials_ Part I

Grade 2- Fall Semester 2020-2021

Tishk International University

Engineering Faculty

Mechatronics Department

Lecture 4_07/11/2020 Dr. Dlair O. Ramadan 1

Dr. Dlair O. Ramadan Lecture 4_07/11/2020 2

Contents Materials in Manufacturing

Metals

Ceramics

Polymers

Composite


Materials in Manufacturing

Most engineering materials can be classified into one of three basic categories:

1. Metals

2. Ceramics

3. Polymers

• Their chemistries are different

• Their mechanical and physical properties are dissimilar

• These differences affect the manufacturing processes that can be used to

produce products from them.



Usually alloys, which are composed of two or more elements, at least one of which is metallic

▪ Two basic groups:

1. Ferrous metals - based on iron, comprises about 75% of metal tonnage in the world:

▪ Steel = Fe-C alloy (0.02 to 2.11% C)

▪ Cast iron = Fe-C alloy (2% to 4% C)

2. Nonferrous metals - all other metallic elements and their alloys: aluminum, copper,

magnesium, nickel, silver, tin, titanium, etc.

a) Metals



a) Metals

High electrical conductivity, high thermal

conductivity, ductile and relatively high stiffness,

toughness and strength. They are ready to machining,

casting, forming, stamping and welding.

Nevertheless, they are susceptible to corrosion.

particularly useful for structural or load-bearing

applications.



a) Metals - General properties

• Electrical wiring

• Structures: buildings, bridges, etc.

• Automobiles: body, chassis, springs, engine block, etc.

• Airplanes: engine components, fuselage, landing gear assembly, etc.

• Trains: rails, engine components, body, wheels

• Machine tools: drill bits, hammers, screwdrivers, saw blades, etc.

• Biomedical


a) Metals _ ApplicationsMaterials in Manufacturing


a) Metals _ Applications


a) Metals _ Applications



b) Ceramics

▪ From the view of processing, ceramics divide into:

1. Crystalline ceramics – includes:

▪ Traditional ceramics, such as clay (hydrous

aluminum silicates)

▪ Modern ceramics, such as alumina (Al2O3)

2. Glasses (amorphous) – mostly based on silica

(SiO2)

• Light weight,

• Hard,

• High strength,

• Stronger in compression than tension,

• Tend to be brittle,

• Low electrical conductivity,

• High temperature resistance and corrosion resistance.



b) Ceramics - General properties

i. Traditional Ceramics: Includes pottery, china, porcelain products…etc, these

products utilizes natural ceramic ores.

ii. Advanced Ceramics: Alumina, magnesia, Carbides, Nitrides, Borides, Silicides

…etc, they are synthetic materials, usually of better mechanical properties.

iii. Glass, Glass Ceramic and Vitro Ceramic : Glasses are essentially vitreous

(amorphous, non crystalline), Glass ceramics are mostly recrystallized from glassy

medium and, Vitro Ceramics have crystalline microstructure which are partially

vitreous at the grain boundaries.



b) Ceramics - Classification

• Electrical insulators

• Thermal insulation and coatings

• Windows, television screens, optical fibers (glass)

• Corrosion resistant applications

• Electrical devices: capacitors, varistors, transducers, etc.

• Highways and roads (concrete)

• Biocompatible coatings (fusion to bone)

• Self-lubricating bearings ?

• Magnetic materials (audio/video tapes, hard disks, etc.)



b) Ceramics - Applications

1. Computer CPUs

2. Electric components (transistors, diodes, etc.)

3. Solid-state lasers

4. Light-emitting diodes (LEDs)

5. Flat panel displays

6. Solar cells

7. Radiation detectors

8. Microelectromechanical devices



b) Ceramics - Semiconductors Applications and Examples

A polymer (the name means "many parts") is long chain molecule made up many

repeating units, called monomers. Polymers can be natural (organic) or synthetic

(Man-Made). The properties of polymers are linked directly to their structure, which

is dictated mostly by intermolecular bonds.

There is different types of polymers. The types include plastics, polystyrene, PVC,

and rubbers.



c) Polymers

Compared with metals:

• Polymers have lower density, lower stiffness and tend to creep.

• Higher thermal expansion and corrosion resistance.

• Lower electrical conductivity and low thermal conductivity.

• The prime weakness is that polymers do not withstand high temperatures.



c) Polymers - General properties

Polymers are everywhere: in plastics (bottles, toys, packaging), cosmetics, shampoos and other

hair care products, contact lenses, nature (crab shells, amber), food (proteins, starches, gelatin,

gum, gluten), fabric, balls, sneakers, and even in your DNA!.



c) Polymers –Applications and Examples

Plastic is a polymer. A couple of examples of plastic polymers are plastic bottles, and a

plastic grocery bags. Carbohydrates is another polymer. Carbohydrates are natural

polymers. Examples of carbohydrates are pasta and bread.




PVC pipe is another example of a synthetic

polymer. PVC piping is made from the synthetic

polymer called polyvinyl-chloride.

Almost all the beverage bottles we use on a daily

basis are made of synthetic polymers. Bottles are

usually made out of a high-density polyethylene.

This tire is made up of synthetic rubber, which is a

synthetic polymer




1. Adhesives and glues

2. Containers

3. Moldable products (computer casings, telephone handsets, disposable razors?)

4. Water-resistant coatings (latex)

5. Biomaterials (organic/inorganic interfaces)

6. Liquid crystals

7. Low-friction materials (Teflon)

8. Synthetic oils and greases

9. Gaskets and O-rings (rubber)




according to their properties:

i. Plastics: (Hard),

Plastics are classified into two categories according to what happens to them when they're heated

to high temperatures. Thermoplastics keep their plastic properties: They melt when heated, then

harden again when cooled. Thermosets, on the other hand, are permanently "set" once they're

initially formed and can't be melted. If they're exposed to enough heat, they'll crack or become

charred.

they can be semi-crystalline or amorphous (glassy).

1. Thermoplastics: Such as Polyethylene (PE) and Polymethylmethacrylate (Acrylic

and PMMA) are composed of “linear” polymer chains. They flow under shear when

heated. They can be compression- or injection- molded.

2. Thermosets: Such as Polystyrene (PS) and Polyvinylchloride (PVC) are composed

of “branched” polymer chains. They not flow when heated. The monomers are

‘cured’ in a mold (‘RIM’).

ii. Elastomers: (Soft) Rubbery cross-linked solids that will deform elastically under stress,

e.g. natural rubber Thermoplastic elastomers are a special type of elastomer in which the

cross-linking becomes reversible upon heating.



c) Polymers – Classification



c) Polymers – Classification

• A combination of two or more materials to achieve better

properties than that of the original materials. These materials

are usually composed of a “Matrix” and one or more of “Filler”

material.

• The primary objective of engineering composites is to increase

strength to weight ratio.

• Composite material properties are not necessarily isotropic, i.e.,

directional properties can be synthesized according to the type

of filler materials and the method of fabrication.



d) Composite



d) Composite

Material consisting of two or more phases that are processed separately and then

bonded together to achieve properties superior to its constituents

▪Phase - homogeneous mass of material

▪Usual structure consists of particles or fibers of one phase mixed in a second

phase

▪Properties depend on components, physical shapes of components, and the way

they are combined to form the final material



d) Composite

This photograph represents the morphology of epoxy rubber

composites. Epoxy takes ninety volume %. Rubber only takes

ten volume %. These black particles represent rubber particles.

Epoxy is brittle, while rubber is very ductile. So mixing ductile

rubber particles with epoxy certainly toughens epoxy.

Ceramic - Polymer Composites

• Low weight,

• High stiffness.

• Brittle.

• Low thermal conductivity.

• High fatigue resistance.

• Their properties can be tailored according to the component materials.



d) Composite - General properties

I. Particulate composites (small particles embedded in a different material):

e.g. Cermets (Ceramic particle embedded in metal matrix) and Filled

polymers.

II. Laminate composites: e.g. (golf club shafts, tennis rackets).

III. Fiber reinforced composites: e.g. Fiber glass (GFRP) and Carbon-fiber

reinforced polymers (CFRP)



d) Composite - Classification

• Sports equipment (golf club shafts, tennis rackets, bicycle frames)

• Aerospace materials

• Thermal insulation

• Concrete

• "Smart" materials (sensing and responding)

• Brake materials



d) Composite - Applications

Summary of some types of materials:


Date post:	14-Feb-2022
Category:	Documents
Upload:	others
View:	2 times
Download:	0 times

Manufacturing Technology - lecture-notes.tiu.edu.iq

Documents