Chapter 4: Imperfections In Solids

Front 1

Imperections

Back 1

Various defects in solids

Front 2

Crystalline defect

Back 2

Lattice irregularity having one or more of its dimensions on the order of atomic diameter

Front 3

Point Defect

Back 3

Defect associated with one or two atomic positions

Front 4

Vacancy

Back 4

Vacant lattice site

Front 5

N.v

Back 5

Equilibrium number of vacancies

Front 6

Equation for N.v

Back 6

N.v=Nexp(-Q.v/kT)Boltzmann's constant

Front 7

N in N.v=Nexp(-Q.v/kT)

Back 7

Total number of atomic sites

Front 8

Q.v in N.v=Nexp(-Q.v/kT)

Back 8

Energy required for formation of a vacancy

Front 9

Boltzmann's constant (k in N.v=Nexp(-Q.v/kT))

Back 9

1.38E(-23) J/atom*K
8.62E(-5) eV/atom*K

Front 10

Fraction of vacancies N.v/N

Back 10

10^(-4)

Front 11

Self-interstitial

Back 11

Atom from crystal that is crowded into an interstitial site, a small void space that under ordinary circumstances is not occupied

Front 12

Alloys

Back 12

Materials in which impurity atoms have been added intentionally to impart specific characteristics

Front 13

Solid Solution

Back 13

Formed with the addition of impurity atoms

Front 14

Solute

Back 14

Element or compound present in a minor concentration

Front 15

Solvent

Back 15

Element or compound present in the greatest amount (also called host atoms)

Front 16

Substitutional Solid Solution

Back 16

Solute (impurity atoms) replace or substitute for host atoms

Front 17

Interstitial Solid Solution

Back 17

Impurity atoms fill voids or interstices among host atoms

Front 18

Composition

Back 18

Concentration^3; determined by constituents of elements

Front 19

Weight Percent (wt%)

Back 19

Weight of particular element relative to total alloy weight

Front 20

Weight Percent (wt%) Equation

Back 20

C.1 = m.1/(m.1+m.2) * 100

Front 21

Atom Percent (at%)

Back 21

Number of moles in relation to the total moles of elements in the alloy

Front 22

n.m1=m'.1/A.1

Back 22

Equation for number of moles in specified mass of hypothetical element

Front 23

Concentration Equation (kg/m^3)

Back 23

C''.1 = { C.1 / [ (C.1/P.1) + (C.2/P.2) ] } * 10E3

Front 24

Dislocation

Back 24

Linear (One-dimensional defect) around which some atoms are misaligned

Front 25

Edge dislocation

Back 25

Linear defect that centers on the line that is defined along the end of the extra half-plane of atoms

Front 26

Dislocation line

Back 26

Line along end of extra half-plane of atoms

Front 27

Screw dislocation

Back 27

Upper front of region is shifted one atomic distance to the right relative to the bottom portion

Front 28

Mixed disolcation

Back 28

Combination of two types of dislocations

Front 29

Burgers vector (b)

Back 29

Describes magnitude and direction of lattice distortion

Front 30

Screw dislocation and Burgers

Back 30

Which dislocation?
Burgers vector is parallel

Front 31

Edge dislocation and Burgers

Back 31

Which dislocation?
Burgers vector is perpindicular

Front 32

Mixed dislocation and Burgers

Back 32

Which dislocation?
Burgers vector is neither perpendicular or parallel

Front 33

Grain boundary

Back 33

Interfacial defect where boundary separates two small grains or crystals have different crystallographic orientations in polycrystalline materials

Front 34

Phase boundary

Back 34

Boundary in multiphase materials

Front 35

Twin boundary

Back 35

Special type of grain boundary across which there is a specific mirror lattice symmetry

Front 36

Domain wall

Back 36

Boundary that separates regions with different directions of magnetization (ferromagnetic and ferrimagnetic materials)

Front 37

Atomic vibration

Back 37

Atomic movement about its lattice position within the crystal

Front 38

Typical vibrational frequency

Back 38

10E13

Front 39

Microstructure

Back 39

Structure that must be analyzed using microscope (i.e grain size and shape)

Front 40

Microscopy

Back 40

Analysis of microscopic structures

Front 41

Photomicrograph

Back 41

The photograph on which the microscopic image is recorded

Front 42

High-Velocity electron

Back 42

Particle for which wavelength is inversely proportional to velocity

Front 43

Transmission electron microscope (TEM)

Back 43

Creates image formed by electron beam that passes through a specimen

Front 44

Scanning electron microscope (SEM)

Back 44

Surface of a specimen to be examined is scanned with electron beam and reflected beam of electrons is collected

Front 45

Scanning probe microscope (SPM)

Back 45

Microscope that generates a topographical map on an atomic scale that is a representation of surface features and characteristics of the specimen being examined

Front 46

Grain size

Back 46

Determined when properties of a polycrystalline material are under consideration
Average volume, diameter, or area

Front 47

Grain size number equation

Back 47

N=2^(n-1)