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ENGINEERING

MATERIALS

Introduction

Dr. Aneela Wakeel (Lec-1)

Engineering Materials Course learning outcomes(CLO) CLO Statement Program Learning Objectives(PLO) Bloom Taxonomy 1 Explain different material types in terms of bonding and crystal structure 1(Engineering knowledge) C2(Comprehension) 2 Read and analyze Phase- Diagrams and effects of heat treatments on microstructure and mechanical properties of ferrous materials 2(Problem analysis) C4 (Analysis) 3 Categorize the metallic materials, polymer, and composite based on structure, properties, and application 2(Problem analysis) C4 (Analysis) 4 Describe materials effects in terms of environment and sustainability 7(Environment and Sustainability) C (Comprehension)

RECOMMENDED BOOKS ❖MATERIAL SCIENCE AND ENGINEERING, BY WILLIAM CALLISTER & DAVIS G RETHWISCH, EIGHTH EDITION, SI VERSION, JOHN WILEY & SONS ❖INTRODUCTION TO ENGINEERING MATERIALS, BY WILLIAM F. SMITH. ❖ROY A. LINDBERG, PROCESSES AND MATERIALS OF MANUFACTURING

Evolution of materials A familiar item that is fabricated from three different material types is the beverage container. Beverages are marketed in aluminum (metal) cans (top), glass (ceramic) bottles (center), and plastic (polymer) bottles (bottom).

• Initially natural materials
• Develop techniques to produce materials with superior qualities (heat

treatments and addition of other substances)

Materials ages

Materials Science and Engineering structure properties

• material characteristic
• response to external stimulus
• mechanical, electrical, thermal, magnetic, optical, deteriorative performance
• behavior in a particular application
• arrangement of internal components
• subatomic
• atomic
• microscopic
• macroscopic (bulk)
• method of preparing material processing characterization

Why study materials?

• Applied scientists or engineers must make material choices
• materials selection
  • in-service performance (properties-trade off)
  • Deterioration (elevated temp, Corrosion)
  • Economics (glass-plastic)

Classification of Materials

Ceramics

• relatively stiff and strong
• thermally and electrically insulating
• resistant to high temperatures and

harsh environments

• hard, but brittle Ceramics are compounds between metallic and nonmetallic elements; they are most frequently oxides, nitrides, and carbides. materials include aluminum oxide (or alumina,Al2O3), silicon dioxide (or silica,SiO2), silicon carbide (SiC), silicon nitride (Si3N4) Traditional ceramics—those composed of clay minerals (i.e., porcelain), as well as cement, and glass Common objects that are made of ceramic materials: scissors, a china tea cup, a building brick, a floor tile, and a glass vase.

Polymers-plastic and rubber materials

• low density,
• Mechanical property may be

extremely flexible ductile and

pliable (i.e., plastic), which means

they are easily formed into

complex shapes

• have low electrical conductivities

and are nonmagnetic

Some of the common and familiar polymers are polyethylene (PE), nylon, poly(vinyl chloride) (PVC), polycarbonate (PC), polystyrene (PS), and silicone rubber Figure. Several common objects that are made of polymeric materials: plastic tableware (spoon, fork, and knife), billiard balls, a bicycle helmet, two dice, a lawnmower wheel (plastic hub and rubber tire), and a plastic milk carton

Composite

carbon fiber reinforced

polymer” (or “CFRP”)

composite—carbon fibers that

are embedded within a

polymer. These materials are

stiffer and stronger than the

glass fiber-reinforced materials

They are more expensive.

The CFRP composites are

used in some aircraft and

aerospace applications, as well

as high-tech sporting

equipment (e.g., bicycles, golf

clubs, tennis rackets, and

skis/snowboards) fiberglass surfboards

Classification of Materials: A Few Additional Categories Biomaterials

• implanted in human body
• compatible with body tissues Semiconductors - electrical properties between conductors and insulators - electrical properties can be precisely controlled Intel Pentium 4 hip replacement

Smart materials