TEST 1 Flashcards
Mark each of the following terms that represent a typical materials group. (Note: all groups may not be listed.)
a) Metals
b) Concrete
c) Semiconductors
d) Woven Materials
e) Polymers
f) Composites
Metals
Semiconductors
Polymers
Composites
Which one of the following statements is not a typical characteristic for a metal?
a) high strength and stiffness
b) lustrous
c) good electrical and thermal conductivity
d) brittle
e) crystalline
Brittle
The bond type in diamond is:
a) ionic
b) metallic
c) covalent
d) secondary
covalent
The major bond type in metals is:
a) ionic
b) metallic
c) covalent
d) secondary
metallic
Ceramics are usually:
a) compounds of metallic and nonmetallic elements
b) made up of two different metallic elements
c) a combination of two or more material types with one serving as a reinforcement
d) made up of long, chain-like molecules
compounds of metallic and nonmetallic elements
Which one of the following statements is not a typical characteristic for a
ceramic?
a) good ductility and formability
b) poor electrical and thermal conductivity
c) excellent high temperature resistance
d) high hardness
good ductility and formability
Which of the following materials is not a ceramic?
a) Al2O3
b) Zn
c) MgO
d) SiO2
e) WC
Zn
The bond type in which valence electrons are not bound to an atom in the solid but drift around and form a “sea of electrons” is:
a) covalent
b) ionic
c) metallic
d) van der Waals
metallic
The bond type in which electrons are shared between adjacent atoms to form a stable group of 8 electrons is:
a) metallic
b) ionic
c) covalent
d) van der Waals
covalent
A polymer that softens when heated but becomes brittle when cooled is
a) thermoplastic
b) thermosetting
thermoplastic
Materials formed from two or more materials (as opposed to elements) that produce unique properties that are not attainable from one group alone are:
a) metals
b) ceramics
c) composites
d) polymers
e) semiconductors
composites
Some of the more expensive golf clubs use “graphite shafts”. What does this really mean?
a) the shaft is solid, high-strength carbon
b) the shaft is a carbon matrix, carbon fiber reinforced material
c) the shaft is a polymer matrix, carbon fiber reinforced material
d) the shaft is a carbon matrix, glass fiber reinforced material
e) the shaft is a polymer matrix, carbon aggregate reinforced material
the shaft is a polymer matrix, carbon fiber reinforced material
A material that exhibits only short range order is called
a) crystalline
b) ionic
c) amorphous
d) irregular
e) covalent
amorphous
The smallest subdivision of a crystalline structure that retains the characteristics of the entire lattice is called a
a) lattice point
b) lattice parameter
c) crystal
d) lattice plane
e) unit cell
unit cell
Are amorphous structures more likely to be found in materials that have complex molecules/structures or in materials with simple structures?
a) complex
b) simple
complex
Which one of the following terms best describes the structure of a glass?
a) single crystal
b) amorphous
c) polycrystalline
d) polymeric
amorphous
Do amorphous materials have grain boundaries?
a) yes
b) no
no
A vacancy consists of
a) an extra atom between normal lattice points
b) a missing plane
c) an extra plane in a crystal
d) a missing atom on a lattice site
e) an extra half-plane of atoms
a missing atom on a lattice site
Calculate the number of vacancies expected in one cubic centimeter of aluminum at 550°C. The activation energy for vacancy formation is 16,890 cal/mol. Aluminum contains 6.02 x 1022 atoms/cm3. Please show your work and mark the appropriate answer.
a) 5.10 x 1021
b) 1.50 x 1021
c) 1.17 x 1016
d) 1.97 x 1018
e) 6.02 x 1019
1.97x10^18
An interstitial consists of
a) an extra single atom between normal lattice points
b) a missing plane
c) an extra plane in a crystal
d) a missing atom on a lattice site
e) an extra half-plane of atoms
an extra single atom between normal lattice points
An edge dislocation consists of
a) a spiral stacking of crystal planes around the dislocation line
b) a change in stacking sequence
c) an extra half plane of atoms
d) an extra single atom between normal lattice points
an extra half plane atom
Do dislocations move or remain fixed in a material during deformation?
a) remain fixed
b) move
move
For a metal of a given composition, which would you expect to have the higher strength? A sample with a fairly low number of dislocations or a sample with a very large number of dislocations?
a) a high number
b) a low number
a high number
What do you expect would happen to the yield strength of a high purity metal if you added atoms of a different type?
a) The yield strength would decrease
b) The yield strength would increase
c) There would be no change
the yield strength would increase
