QUIZ 1 Flashcards
1
Q
Substances of which something is made from
A
Materials
2
Q
Investigates the relationships that exists between STRUCTURE and PROPERTIES of materials
A
Materials Science
3
Q
A scientific discipline concerned with the search for basic knowledge about the INTERNAL STRUCTURE, PROPERTIES AND PROCESSING of materials
A
Materials Science
4
Q
Materials whose structures are designed to develop specific properties for a given application
A
Engineering materials
5
Q
To continue to provide consumers with what they expect and need, designers must keep abreast with ______
A
new materials development
6
Q
From teh structure property relationship, the material’s structure is ENGINEERED to produce a predetermined set of properties
A
materials engineering
7
Q
An engineering discipline which is primarily concerned with the use of the fundamental and applied knowledge of materials so that they can be converted into products needed or desired by society
A
Materials science and engineering
8
Q
Relates to the internal arrangement of a materials’ internal components
A
Structure
9
Q
involves electrons and interactions within the nuclei
A
subatomic
10
Q
arrangement of atoms or molecules relative to one another
A
atomic
11
Q
large groups of atoms observed through a microscope
A
microscopic
12
Q
structural elements visible through the naked eye
A
macroscopic
13
Q
a material trait in terms of the kind and magnitude of response to a specified imposed stimulus
A
property
14
Q
generally, definitions of properties are independent of the material’s shape and size
A
property
15
Q
deformation to an applied load or force
A
mechanical property
16
Q
the tendency of the object to be deformed elastically upon the application of forcee
A
elastic modulus
17
Q
the ability to withstand an applied stress without failure (deformation that cannot be reversed).
A
Strength
18
Q
Response from an electric field
A
Electrical Property
19
Q
the ability to conduct electric
current.
A
Electrical conductivity
20
Q
Stimulus to a magnetic field
A
Magnetic Property
21
Q
– is the measure of the resistance of a
ferromagnetic material to becoming demagnetized
A
Coercivity
22
Q
Response to heat
A
Thermal Property
23
Q
is the property of a
material that indicates
its ability to conduct
heat.
A
Thermal conductivity
24
Q
Stimulus to electromagnetic or light radiation
A
Optical Property
25
the property of a material to
| allow light to pass through
Optical Transmission
26
light passes through completely
Transparent
27
light passes through diffusely
Translucent
28
– does not allow light to pass through
Opaque
29
Reactivity of materials to
| chemicals.
Deteriorative Property
30
```
– the
disintegration of an
engineered material into
its constituent atoms due
to chemical reactions with
its surroundings,
commonly with oxygen
(oxidation).
```
Corrosion
31
```
In the sense of materials science and
engineering, processing refers to the
altering of the structure of a material in
order to come out with a desired set of
properties
```
Processing
32
heating the metal to above the
| recrystallization temperature and mainta
Annealing
33
– accomplished by a controlled
reheating of the work piece to a temperature
below its lower critical temperature
Tempering
34
heating the metal until the crystal
| structure changes.
Austentizing
35
rapidly cooling the metal.
Quenching
36
The metal’s structure is not regular throughout.
Crystal grain
37
Metallic elements, e.g. iron, silver
Metals
38
Compounds of a metal and non-metal
Ceramics
39
Materials with long hydrocarbon chains, e.g.
plastics
A material composed of a combination of
metals, ceramics, and/or polymers
Polymers
| Composites
40
Materials that are implanted into the human
body for replacement of diseased or damaged
parts
Materials whose properties lie between a
conductor and insulator, and find applications in
electronics
Biomaterials
| Semiconductors
41
```
The atom is composed of a
_______ composed of
protons and neutrons, with
the electrons circling around
the nucleus in ______
```
nucleus
| shells.
42
Some elements have different number of
neutrons, thus having two or more atomic
masses. These are called ______
isotopes.
43
The _____ is the weighted average of
the atomic masses of the atom’s naturally
occurring isotopes.
atomic weight
44
1 amu is defined as ____ of the
atomic mass of the most common isotope of
_____
1/12
| carbon
45
1 mole = _____atoms or molecules
The two schemes are related by
1 amu/atom (or molecule) = 1 g/mol
* This is known as ______where A =
6.023x10^23 atoms/mole
| Avogadro’s Number,
46
has electrons revolving
around the nucleus in discrete
orbital shells.
Bohr atomic model
47
```
Each electron has a particular
value of energy (quantized) by
making a quantum jump to a
higher level by absorption of
energy, or to a lower energy
level by emission of energy.
These are termed as _____ or _____
```
energy
| levels or states.
48
Makes up for the limitation of
| the Bohr model.
Wave mechanical model
49
Considers the electron to
| have wave-like and particle like characteristics.
Wave mechanical model
50
```
The electron’s position is no
longer defined as a discrete
orbital, but as a probability of
an electron being at various
locations (probability
distribution or electron cloud).
```
Wave mechanical model
51
Specifies the size, shape, and spatial orientation
| of the electron’s probability density.
Quantum Numbers
52
Dictates the number of states within each
| electron subshell
Quantum Numbers
53
Shells are specified by a _____ having integral values (n = 1, 2, 3,…).
Sometimes they are designated by letters (K, L,
M,…). This relates the distance of the electron
from the nucleus.
principal quantum
| number,
54
The number of states for each subshell is
defined by the ____, ml. s, p,
d, and f subshells have 1, 3, 5, and 7 states
respectively
third quantum number
55
The _______ l, signifies the
subshell denoted by a lower-case letter – an s,
p, d, or f, relates the shape of the subshell.
second quantum number
56
______ for an electron can either be up or
down, and is related by a fourth quantum
number ms, with two possible values (+½ or -½).
Spin moment
57
Elements are arranged according to electron
| configuration.
Periodic Table of Elements
58
Elements with increasing atomic
numbers are arranged in seven horizontal rows
called____. Each column or _____ of
elements have similar valence electron
structures, as well as chemical and physical
properties.
periods
column or group
59
Consider two isolated atoms brought into close
proximity from infinity. At large distances, the
interactions are ______. As the atoms
approach, each exerts a force on the other,
repulsive and attractive.
negligible
60
The net force FN between the two atoms is
| _____ (give formula)
Fn = Fa + Fr
61
The net force is a function of the ______ r.
interatomic
| separation
62
When FA and FR balance, there is a net force. true or false
false. no net force = 0
63
For many atoms, r0 is
| approximately _____.
0.3 nm (3Å)
64
Force and energy are related mathematically by ____ (give formula)
E = integral of (Fdr)
65
_______ is the minimum amount of
energy that would be required to separate the
two atoms
Bonding energy (E0)
66
Found in compounds composed of metallic and
non-metallic elements, elements situated at the
horizontal extremities of the table.
Ionic Bonding
67
Atoms of a metallic element _____ their
| valence electron to the non-metallic element.
give up
68
In the process of ionic bonding, they acquire a stable state or
________, and in addition, an
electrical charge (they become ions).
inert gas configuration
69
example of ionic bonding
Table Salt (NaCl)
70
Attractive bonding forces are _____, i.e.,
positive & negative ions, by virtue of their
electrical charge, attract one another
coloumbic
71
Ionic bonding is _______, magnitude of
| bond is uniform in all directions around an ion.
non-directional
72
Predominant bonding scheme in ceramics
ionic Bonding
73
Ionic compounds have high bonding energies
(600-1500 kJ/mol), reflected in ____ melting
temperatures, hard and brittle, and electrically
and thermally insulative.
high
74
Sharing of electrons between two adjacent
| atoms
Covalent Bonding
75
______atoms will contribute at least
one electron to the bond, with the shared
electron belonging to both atoms.
Covalently bonded
76
example of covalent bonding
methane
77
Covalent bond is _____, it is between
specific atoms and may exist only in the
direction between one atom and another that
participates in the electron sharing.
directional
78
Number of covalent bonds that is possible for an
| atom is determined from its ______
valence electrons,
79
_____ materials typify covalent bond, being
| composed of long carbon structures.
Polymeric
80
It is _______ to have interatomic bonds that are
partially ionic and partially covalent, and, in fact,
very few compounds exhibit pure ionic or
covalent bonds. (possible or not possible)
possible
81
For a compound, the degree of either bond type
depends on the relative position of the
constituent atoms in the periodic table
(electronegativity). The _____ the degree of
electronegativity (horizontally or vertically), the
____ ionic the bond. Conversely, the ____the
atoms are together, the _____ the covalency.
greater, more
closer , greater
82
bonding found in metals and alloys
metallic bonding
83
Valence electrons are not bound to any
particular atom and are more or less free to drift
throughout the entire metal. what bonding
metallic bonding
84
Free electrons form an _______
electron cloud
85
The non-valence electrons and nuclei form what
are called ______, which posses a positive
charge equal in magnitude to the total valence
electron charge per atom (due to the electron
not being attached to the atom).
ion cores
86
example of metallic bonding
gold
87
Metallic bonds are
| directional or non-directional?
non-directional
88
A material in which the atoms are arranged in
periodic arrays over large distances (existence
of long-range order)
Crystalline Material
89
All metals, many ceramics, and certain polymers
| form ______upon solidification.
crystalline structures
90
Compounds which do not crystallize, or for
which long-range order is absent, are termed
non-crystalline or _______
amorphous
91
Manner in which atoms, ions, or molecules are
| spatially arranged.
Crystal Structure
92
Crystalline structures are thought of as solid
spheres with well-defined diameters, termed as
_______, in which spheres
representing nearest neighbor atoms touch one
another.
atomic hard spheres
93
Used in the context of crystal structures
Lattice
94
A three-dimensional array of points, coinciding
| with atom positions (or sphere centers).
Lattice
95
Smallest repeating unit
| within a crystal structure.
Unit Cell
96
```
For most crystal
structures, unit cells are
____ or _____,
having three sets of
parallel faces.
Represents the
```
parallelipipeds, or prisms
97
Atoms are located at each of the corners and
| centers of the cube faces.
Face-centered Cubic (FCC)
98
give examples of FCC elements
Copper
Silver
Aluminum
Gold
99
Each corner atom is shared among eight unit
cells & the face centered atoms belong to two,
or, there are 8 1/8 atoms and 6 ½ atoms, a total
of 4 atoms per unit cell.
Face-centered Cubic (FCC)
100
Translation of the cube from a corner to a face
| center will not alter the cell structure.
Face-centered Cubic (FCC)
101
Atoms are located at the eight corners and at the
| center of the cube.
Body-centered Cubic (BCC)
102
give examples of BCC elements
Chromium
Iron
Tungsten
103
There are 8 1/8 atoms and 1 whole atom per unit
| cell, a total of 2
Body-centered Cubic (BCC)
104
Number of nearest neighbor or touching atoms
| for a particular atom.
Coordination Number
105
FCCs have a coordination number of ____.
| BCCs have a coordination number of ____.
12
| 8
106
Fraction of a solid sphere inside a unit cell
Atomic Packing Factor (APF)
107
give the formula of Atomic Packing Factor (APF)
APF = total volume of atoms/volume of unit cell
108
APF of fcc
0.74048
109
APF of bcc
0.680175
110
Length of side of cell, in fcc
s = 2r sqrt(2)
111
Length of side of cell, in bcc
s = 4r/sqrt(3)
112
The unit cell is a hexagonal
| prism.
Hexagonal Close-packed (HCP)
113
prism.
Atoms are located at the
corners and the center of the
2 hexagonal planes.
Hexagonal Close-packed (HCP)
114
Another plane in-between the
hexagonal planes contain ___
atoms
3
115
```
Contains 6 1/6 atoms and 1 ½
atom for each of the top and
bottom planes, a 3 atoms in
the middle plane; a total of 6
atoms per unit cell.
```
Hexagonal Close-packed (HCP)
116
elements that have HCP structures
Cadmium
Zinc
Magnesium
117
Some metals, as well as non-metals, may have
more than one crystal structure.
This phenomenon is known as ______.
When formed in elemental solids, this condition
is often termed as _____
polymorphism
| allotropy.
118
The prevailing crystal structure depends on both
| the _____ and _____
temperature
| external pressure.
119
```
Unit cell geometry is
completely defined in
six parameters: edge
lengths a, b, c; and
three internal angles
, β, γ, sometimes
called _____
```
lattice
| parameters.
120
WHAT ARE THE seven crystal systems
```
Cubic
Hexagonal
Tetragonal
Orthorhombic
Rhombohedral
Monoclinic
Triclinic
```
121
When dealing with crystalline structures, it
becomes necessary to specify a particular
crystallographic plane of atoms or a
_______
crystallographic direction
122
____ integers of indices are used to designate
directions and planes, based on a unit cell,
situated at one corner.
Three
123
A line between two points, or a vector.
crystallographic direction
124
In cubic crystals, several crystal directions are
equivalent and grouped in angle brackets is
called a ____. Furthermore, directions having
the same indices without regard to order or
sign are ______
family
| equivalent.
125
in hexagonal crystals, we will use a 4-axis, or______
| coordinate system.
Miller-Bravais,
126
in miller-bravais coordinate system, Axes a1, a2, and a3 are contained on a single
plane, called the ____, and are at 120° to
each other. The z-axis is perpendicular to the
basal plane
basal plane
127
Crystallographic planes are represented by
three ______(except in hexagonal
crystals). Any two planes parallel to each other
are equivalent and have identical indices.
Miller indices hkl
128
For cubic systems, planes and directions having
the same indices are _______ to one
another, but may not be the case for other
crystal systems.
perpendicular
129
Atomic arrangements for a particular plane of
| interest depends on the ______
crystal structure.
130
A _______contains all those planes that
are crystallographically equivalent – that is
having the same atomic packing.
family of planes
131
the fraction of the line length in
a particular crystallographic direction that
passes through the atom centers.
Linear density
132
– the fraction of the total
crystallographic plane area that is occupied by
atoms passing through the atom centers
Planar density
133
which crystal structures have the most efficient packing of atoms? give the value of apf
FCC AND HCP
| 0.74048
134
Single crystals exist in nature, but can also be artificially
grown.
Good examples are _______.
gemstones
135
The atoms are arranged in perfect, periodic arrays and
| extends throughout the specimen without interruption.
Single crystal
136
Composed of many small crystals or grains
Polycrystalline material
137
The region where two crystals meet is termed as the
| _____________.
grain boundary
138
The physical properties of single crystals of some
| substances depend on the crystallographic direction
Anisotropy
139
Properties like elastic modulus and electrical conductivity
may have different values in the [100] and [111]
directions.
The directionality of these properties is termed as
_______.
anisotropy.
140
_____________ lack a systematic and regular
| arrangement of atoms over relatively large distances.
Noncrystalline solids
141
other term for noncrystalline solids
amorphous.
142
________ crystals are characterized by complex
molecular structures that can become ordered with some
difficulty
Amorphous
143
give the formula of true density
rho = nA/VcNa
144
For regular HCP crystals, the
ratio c/a should be _______
But some metals deviate from
this ratio.
1.63299.
145
APF of HCP
0.74048.
