Imperfection in Solids

Question 1

such an
idealized solid does not exist; all contain
large numbers of various defects or

Answer 1

imperfections

Question 2

refers to a lattice
irregularity having one or more of
its dimensions on the order of an
atomic diameter. Classification of
crystalline imperfections is
frequently made according to the
geometry or dimensionality of the
defect

Answer 2

Crystalline Defect

Question 3

responsible for reductions of
gas pollutant emissions from

Answer 3

atomic defects

Question 4

the simplest of the point one
normally occupied but from which an atom is missing defects

Answer 4

Vacancy or vacant lattice site

Question 5

the presence of vacancies increases the
___ (i.e., the randomness) of the
crystal.

Answer 5

entropy

Question 6

is an atom
from the crystal that is crowded
into an interstitial
site—a small void space that
under ordinary circumstances is
not occupied.

Answer 6

self-interstitial

Question 7

Solids are like humans, they are not perfect. They also have ___

Answer 7

defects

Question 8

imperfection in/of solids

Answer 8

•Point Defects
•Impurities in solids
•Linear Defects (dislocation)

Question 9

A ___ forms when, as the solute atoms are
added to the host material, the crystal structure is
maintained and no new structures are formed.

Answer 9

solid solution

Question 10

A solution is composed of two parts:

Answer 10

solute and a
solvent or the host

Question 11

Impurity point defects are found in solid solutions,
of which there are two types:

Answer 11

Substitutional solid solution
2.) Interstitial solid solution

Question 12

Appreciable quantities of a solute may be
accommodated in this type of solid solution only when
the difference in atomic radii between the two atom types is
less than about 15%. Otherwise, the solute atoms create
substantial lattice distortions and a new phase forms.

Answer 12

Atomic size factor

Question 13

For appreciable solid solubility, the crystal
structures for metals of both atom types must be the same.

Answer 13

crystal structure

Question 14

The more electropositive
one element and the more electronegative
the other, the greater the likelihood that they will
form an intermetallic compound instead of a
substitutional solid solution.

Answer 14

electronegativity factor

Question 15

Other factors being equal, a metal has more of
a tendency to dissolve another metal of higher valency than
to dissolve one of a lower valency.

Answer 15

valences

Question 16

impurity atoms fill the voids
or interstices among the
host atoms

Answer 16

Interstitial solid solution

Question 17

two types of interstitial
sites

Answer 17

tetrahedral and
octahedral

Question 18

the number of nearest
neighbor host atom

Answer 18

coordination

Question 19

___ have relatively high atomic packing
factors, which means that
these interstitial positions are relatively small.

Answer 19

metallic materials

Question 20

the maximum allowable concentration of interstitial impurity
atoms is low

Answer 20

less than 10%

Question 21

Even very small impurity atoms are ordinarily larger than the
interstitial sites, and as a consequence, they introduce some ___ on the adjacent host atoms

Answer 21

lattice strains

Question 22

(wt%) is the weight of a particular element
relative to the total alloy weight.

Answer 22

Weight percent