Materials Science MTL200
Course Evaluation
Assignments :
7.5%
Term Test:
20%
Labs:
17.5%
Final Exam:
55%
Last Class: Wed. April 10th , 2024
Important Dates: Midterm Test : Tues. March 12, 2024
Final Exam: TBA
Materials Science MTL200
Objectives:
To understand materials fundamental concepts.
To characterize structure of materials with their crystal
structures, microstructures, and phase diagrams.
To understand the influence of the structure of
materials on mechanical properties.
To learn techniques evaluating the mechanical
properties of materials .
Course Outline
Materials
Science
Introduction to Engineering Materials
Atomic Bonding
Crystal Structure
Phase Diagrams
Mechanical Properties of Materials
Ceramics
Polymers
Composites
Corrosion
Tes
t
Laboratory Experiments for Materials Science (MTL 200)
Sections 01-04
Experiment 1: Construction of Atomic Model and Crystal Structures
Objective: The study of metallic crystal structure models:
•FCC (Face-Centred-Cubic),
•BCC (Body-Centred Cubic), and
•HCP (Hexagonal Closed-Packed)
This experiment is to understand how important are both atomic arrangement
and crystal structures in mechanical properties of materials.
Experiment 2: X-ray Diffraction Analysis
Objective: X-ray diffraction will be used to identify materials and their
substances.
Experiment 3: Phase Diagram Determination
Objective: The study of lead-tin phase diagram from thermal data
Experiment 4: Corrosion of Metals
Objective: The study of basic concepts of corrosion of metals including
fundamentals of metal corrosion, forms of corrosion, polarization and
corrosion rate.
Experiment 5: Thermal Behavior of Materials
Objective: The linear expansion of five different materials will be studied. The
coefficient of linear expansion of these materials will be obtained and
compared with the coefficients suggested in the textbook for these materials.
Important notes on MTL200 laboratory
(For in-person lab participation)
Laboratory Reports:
Laboratory Safety Concerns:
Format: A report includes:
Cover page; Full Names and IDs Objective,
Introduction, Test Procedures, Results and
Discussion (accompanied with questions of Lab
manual), Summary and References.
Due Date: The lab reports are due --- week/s
from the date of the experiment was performed.
Group: Every group containing maximum three
students, should submit one Lab report for each
experiment.
Attendance: You have to fill the attendance form
including name, section, experiment, date and
time.
Submission: Drop your Lab report into a box
(located in Materials Laboratory KHE25) with
Prof.’s/TA’s name on it.
In Corrosion Experiment, please do not
touch chemical solutions without gloves. In
any case of chemical solution exposure,
rinse your hands with tap water quickly.
Do not touch furnaces, in Phase Diagram
Experiment. Use gloves when you are
changing specimens in Thermal Expansion
Experiment.
If you broke a piece of Test Equipment
during conducting of your Lab experiment,
please report it quickly to TA or Technical
officer. This provides us enough time to
replace the broken piece and make the Lab
experiments possible for next groups.
Why Do We Study Materials?
Technology development,
Proper selection of materials for
design purposes,
Create new materials and modify
the properties, and
Environmental impact
Materials Science and Engineering
• Materials Science is • Materials Engineering
primarily concerned
is mainly concerned with
with the search for
the use of fundamental
basic knowledge
and applied knowledge
about the internal
of materials that can be
structures, properties converted into products
and processing of
necessary or desired by
materials.
society.
Materials Engineering
Many engineering components and structures
are exposed to a design problem involving
materials.
• Mechanical Engineers search for a high temperature
materials for jet engines,
• Electrical Engineers search for new materials for operating
electronic devices faster and at higher temperature,
• Aerospace engineers search for materials with higher
strength-to-weight ratios for aircraft and space vehicles,
• Chemical engineers look for more highly
corrosion-resistant materials.
Materials Structures
The structure of a material usually relates to
the arrangement of its internal components.
Subatomic structures
Microscopic structures
Macroscopic structures
Materials Classification
• Metals,
• Ceramics,
• Polymers,
• Composites,
• Semiconductors
• Biomaterials
Examples
Al, Cu, Mg, Fe, Co
Al2 O3 (Alumina)
Nylon, Epoxy, Rubber
FRP Composites
Silicon, Germanium
Biocompatible
Materials
Atomic Structures
Properties of solid materials depend on geometrical
atomic arrangement and their bonding.
Atom-each atom consists of three basic
subatomic particles: Protons (+), Neutrons, and
Electrons (-). Nucleus composed of Protons and
neutrons which is encircled by moving Electrons.
Particle Mass (g)
Unit Charge (C)
Proton 1.673x10-24
1.602x10-19
-------------------Neutron 1.675x10-24
Electron 9.109x10-28
1.602x10-19
Atomic Structures
Concepts:
• Atomic number (Z) is the number of protons in
the nucleus.
• Atomic Mass (A) is the sum of the masses of
protons and neutrons within the nucleus.
• Relative atomic mass of an element is the mass in
grams of 6. 023x1023 atoms (Avogadro’s
number) of that element.
Electronic Structure of Atoms
Example: The hydrogen electron being (a) excited in to a
higher orbit, and (b) an electron in a higher energy orbit
dropping to a lower orbit and as a result a photon of energy
(electromagnetic radiation) is emitted.
Photon
Photon
hν
hν
H
H
n=1
n=1
n=2
n=2
n=3
n=3
(a) Energy Absorbed
(b) Energy Emitted
Energy of Transition of an Electron from one
Level to Another
Energy change ΔE is related to the frequency ν of the
photon by Planck’s equation:
Where h=Planck’s constant=6.63x10-34 Joule-Second
For Electromagnetic Radiation,
Where C is velocity of light (3E8 m/sec) and λ is the
wavelength.
The energy change ΔE associated with a photon is
expressed as:
Atomic Models
• Bohr Atomic Model:
In this model electrons are
assumed to revolve around
the atomic nucleus in a
discrete orbital and
position of any electron is
well defined in terms of its
orbital.
• Quantum mechanics:
Every electron in an atom
is characterized by four
parameters called quantum
numbers. The size, shape,
and spatial orientation of
electron’s probability
density are specified by
quantum numbers.
Quantum Numbers
• The principal quantum number (n)
– n=1,2,3,…, 7 (number of atomic shells in Bohr model)
• The subsidiary quantum number (l)
– l=0,1,2,…,n-1 or l=s, p, d, f (number of subshell within
main energy levels)
• The magnetic quantum number (ml)
– Specifies the spatial orientation of a single atomic
orbital.
• The electron spin quantum number (ms)
– Specifies two allowed spin directions for an electron
spinning on its own axis
Atomic Arrangement and Configuration
Example: Write the electron configuration for iron (Z=26).
Method 1:
Method 2:
Method 1
1s
2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f
6s 6p 6d 6f
7s 7p 7d
Method 2
1s
2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f
6s 6p 6d 6f
7s 7p 7d
Electronegativity
Electronegativity is defined as the degree to which an atom
attracts electrons to itself.
• Electronegative
elements readily
accept electrons to
form negatively
charged ions or some
times they share
electrons with other
atoms, e.g., Cl
• Electropositive
elements are capable
of giving up their few
valence electrons to
become positively
charged ions, e.g.,
Metals (Fe, Al).
Electronegativity and Periodic Table
Electronegativity increases from left to right and from bottom
to top of the periodic table.
Atomic Bonding
Physical and mechanical properties of materials depend on
interatomic forces that bind the atoms together. As two
atom approach, each exerts forces on the other. These
forces are of two types:
• Attractive forces (FA)
• Repulsive forces (FR)
The magnitude of each force is function of the interatomic
distance.
The Net force (FN) between the two atoms is just the sum of
both attractive and repulsive forces: FN= FA+ FR
Chemical Bonds Between Atoms
• Primary (Strong) bonds
– Ionic bonding
– Covalent bonding
– Metallic bonding
• Secondary (Weak) bonds
– Van der Waals bonding
– Hydrogen bonding
Primary Bonds
Coulombic bonding force
Cl-
Cl-
Na+
Na+
Cl-
Shared electron
from Carbon
H
Na+
Ion cores
H
C
H
+
+
-
Na
+
Cl
-
Na+
H
+
-
+
+
+
-
+
-
+
-
+
+
Shared electron
from Hydrogen
+
+
+
+
+
+
Sea of valence electrons
Ionic bonding
(NaCl)
Covalent Bonding
(CH4)
Metallic Bonding
(Cu)
Secondary Bonds
-
+
-
+
Figure 1- Schematic illustration of van der Waals
bonding between two dipoles.
Atomic or molecular dipoles
H
F
H
F
Figure 2- Schematic illustration of Hydrogen
bonding in hydrogen fluoride (HF).
Hydrogen bond
Asymmetrical distribution of electron charge in noble-gas
atoms (e.g., Ne and Kr) creates electric dipoles. These dipoles
in atoms create dipole moments. Electric dipoles interact with
each other by electrostatic forces and therefore, atoms are
attracted to each other by these forces.
Bonding Energies
Bonding Type
Substance
Bonding Energy
kJ/mol (kcal/mol)
Ionic
Covalent
Metallic
van der Waals
Hydrogen
Melting Temperature (˚C)
eV/Atom, Ion, Molecule
NaCl
MgO
640 (153)
1000 (239)
3.3
5.2
801
2800
Si
C
450 (108)
713 (170)
4.7
7.4
1400
>3550
Hg
Al
Fe
W
68 (16)
324 (77)
406 (97)
849 (203)
0.7
3.4
4.2
8.8
-39
660
1538
3410
Ar
Cl2
7.7 (1.8)
31 (7.4)
0.08
0.32
-189
-101
NH3
H2O
35 (8.4)
51 (12.2)
0.36
0.52
-78
0
Class Problem 1
(a) What is the mass in grams of one atom of Copper?
(b) How many copper atoms are in one gram of Copper?
Note: the atomic mass of Copper is 63.54 g/mol.
Class Problem 2
The cladding (outside layer) of the US quarter coin consists of an
alloy of 75wt% Copper and 25wt% Nickel. What are the atomic
percent Cu and atomic percent Ni contents of this material?
Note:
The atomic mass of Cu is 63.54 g/mol.
The atomic mass of Ni is 58.69 g/mol.
Class Problem 3
An intermetallic compound has the general chemical formula
NixAly, where x and y are simple integers and consist of 42.04 wt%
Ni and 57.96 wt% Al. What is the simplest formula of this
Nickel-Aluminum alloy?
Note:
The atomic mass of Ni is 58.69 g/mol.
The atomic mass of Al is 26.98 g/mol.
Class Problem 4
Calculate the energy in Joules (J) and electron volts (eV) of the
photon whose wavelength λ is 121.6 nanometers (nm).
Note:
1.00 eV=1.6×10-19J
1nm=10-9m.
Class Problem 5
Write the electron configuration of the following elements:
(a) Fe (Z=26)
(b) Fe+2
(c) Fe+3
(d) Samarium (Z=62)