Презентация на тему Engineering materials

mandatory
Switch off all mobile electronic devices while in class
Grading:

10% Quiz avg.
30% Midterm
60% Final Exam
Cheating will NOT be tolerated
Moodle will be utilized

structure on material properties;
Mechanical properties, failure and strengthening mechanisms;
Applications

and processing of common engineering materials such as metals & nonferrous alloys, ceramics, polymers, and composites;
Economic, environmental and social issues of material usage and considerations for materials selection in designs.

of the course the students will be able to:
Explain

the influences of microscopic structure and defects on material properties, including dislocation and strengthening mechanisms
Design and control heat treatment procedures to achieve a set of desirable mechanical characteristics
Understand the applications and processing of common engineering materials including metals & nonferrous alloys, ceramics, polymers, and composites
Utilize the knowledge in materials selection processes taking further considerations of the economic, environmental and social issues

Engineering: An Introduction, 8th Edition
William D. Callister, David G.

Rethwisch

Engineering Materials 1: An Introduction to Properties, Applications and Design, 4th Edition Michael F. Ashby, D R H Jones

on functions and applications:
Aerospace
Biomedical
Electronic Materials
Energy Technology and Environment
Magnetic Materials
Optical

and Photonic Materials
“Smart” Materials
Structural Materials

L1. Course Overview & Introduction

& Introduction
Classification of Materials Based on chemical makeup and atomic

structure

Materials

Metals

Ceramics

Polymers/plastics

Composites

& Introduction
Properties of Materials classified on basis of chemical makeup

and atomic structure

Metals

Strong, ductile

High thermal conductivity

High electrical conductivity

Not transparent, shiny

& Introduction
Properties of Materials classified on basis of chemical makeup

and atomic structure

Ceramics

Ionic bonding (refractory)

Compounds of metallic & non- metallic elements (oxides, carbides, nitrides, sulfides)

Strong, brittle, may or may not be transparent

Non-conducting (insulators)

& Introduction
Properties of Materials classified on basis of chemical makeup

and atomic structure

Polymers/plastics: chains of organic molecules

Covalent bonding  sharing of electrons

Soft, ductile, low strength, low density

Thermal & electrical insulators

Optically translucent or transparent

& Introduction
Properties of Materials classified on basis of chemical makeup

and atomic structure

Composites

Compounds of two (or more) individual materials (metals, ceramics, polymers) with combination of properties

Engineering
Properties depend on structure, e.g.: steel hardness
Processing can

change structure, e.g.: structure versus cooling rate of steel

L1. Course Overview & Introduction

Engineering
Moulding process
Plastic deformation process
Joining process
Mechanical working process
Heat treatment process
Different

materials should be processed differently; Same materials can be processed differently for different geometries

L1. Course Overview & Introduction

Engineering
Sub atomic level –
e.g. interatomic

bonding
Atomic level –
e.g. arrangement of atoms
Microscopic level –
e.g. grain arrangement seen with microscope
Macroscopic level –
e.g. structural elements view with naked eye

Structure can be viewed in different “length” scales

L1. Course Overview & Introduction

Engineering
Mechanical – response to applied load, e.g. ultimate strength
Electrical

– response to electric field, e.g. resistivity
Thermal – response to heat, e.g. thermal conductivity
Magnetic – response to magnetic field, e.g. magnetic permeability
Optical – response to light, e.g. transparent, translucent, opaque
Deteriorative – relates to chemical reactivity, e.g. heat treatment can slow crack speed of some alloy in salt water

Property is a material trait in terms of the type and magnitude of response to a specific imposed stimulus.

L1. Course Overview & Introduction

Engineering
1.
Pick Application
Determine required Properties
2.
Properties
Identify candidate Material(s)
3.
Material
Identify

required Processing

Processing: changes structure and overall shape
ex: casting, sintering, vapor deposition, doping
forming, joining, annealing.

Properties: mechanical, electrical, thermal,
magnetic, optical, deteriorative.

Material: structure, composition.

L1. Course Overview & Introduction

“Green” – environmentally friendly
Sustainability: e.g. bamboo bicycle frame
Easily available

commercially in large quantities
Political: e.g. sanctions on nuclear materials
Technology: e.g. heat shield for space shuttle
Degradation during service: e.g. corrosion

L1. Course Overview & Introduction

will help you to:
Use the right material for the

job.
Understand the relation between properties,
structure, and processing.
Recognize new design opportunities offered
by materials selection.

You will learn in this module about:
material structure
how structure dictates properties
how processing can change structure
commonly used engineering materials

L1. Course Overview & Introduction

with the atom, atomic bonding, and how different classes

of materials are bonded together
Look at the effect of composition on microstructure
Look at the effect of processing on microstructure
Connect how microstructure relates to properties

We shall first do some revision

L1. Course Overview & Introduction

Engineering
ATOM = (PROTONS+NEUTRONS) +

ELECTRONS

Mass of an atom:
Proton and Neutron: ~ 1.67 x 10-27 kg
Electron: 9.11 x 10-31 kg
Charge:
Electrons and protons: (±) 1.60 x 10-19 C
Neutrons are neutral

L1. Course Overview & Introduction

Engineering
Z = Atomic number = number of protons in

nucleus
This is used to identify element

N = number of neutrons in nucleus
This is used to identify isotopes, written as (Z+N)XZ : ( e.g. 14C6 and 12C6 )
where: A = Atomic mass unit (amu)

1 amu is defined as the 1/12 of the atomic mass 12C6

Atomic mass of 12C6 is 12 amu: 6 protons (Z=6) + 6 neutrons (N=6)

This is approximately the total mass of protons + total mass of neutrons

Therefore 1 amu = Massproton ~ Massneutron = 1.67 x 10-27 kg
and A = Atomic Mass = Z + N
  NAV = 1 mole = 6.023 x 1023 molecules or atoms (Avogadro’s number) Atomic weight is expressed in amu/atom, i.e. 1 amu/atom = 1g/mol

L1. Course Overview & Introduction

Engineering
NA = number of atoms per cm3
 =

material density g per cm3
M = atomic weight of material g per mole
NAV = Avogadro’s number = 6.023 x 1023

L1. Course Overview & Introduction

Engineering
L1. Course Overview & Introduction

the number of atoms per cm3 for Graphite (Carbon)

and Diamond (Carbon) given:
Graphite  = 2.3 g per cm3,
Diamond  = 3.5 g per cm3;

Graphite NA = 11.5  1022 atoms per cm3,
Diamond NA = 17.5  1022 atoms per cm3;
Any ideas why?

L1. Course Overview & Introduction