mse 280

which of the following in NOT a mechanical property?

Thermal conductivity

an amorphous crystal structure has short range order only

true

metals are made up of mostly

metallic elements

the same material that is processed differently will have the same properties

false

metals are usually

crystalline

metals usually are

multi grain

glasses usually are

amorphous

glasses usually are

Neither A nor B are applicable for glass

ceramic usually are

crystalline or a mix of amorphous and crystalline regions

ceramic are usually

multi grain

thermoplastics usually are

amorphous or a mix of amorphous and crystalline regions

thermosets usually are

amorphous

palmers are made up of mostly

nonmetallic elements

ceramic are made up of mostly

a mix if metallic and nonmetallic elements

semiconductors are usually

crystalline

semiconductors are usually

single grain

which material type usually has the highest density

metals

which material type is the least prone to corrosion

ceramics

which material type typically has both high strength and ductility

metals

which material type is the most limited in the temperature that it can operate (high temp.)?

polymers

which material type usually has the lowest density

polymers

which material type usually has the highest stiffness

ceramics

which material type usually has the lowest stiffness

polymers

which material type typically has the highest thermal conductivity

metals

which material type typically has the highest electrical conductivity

metals

which material type typically can be operated at the highest temperature

ceramics

which form of SiO2 is transparent

amorphous SiO2

which form of carbon is the hardest

diamond

which polymer type is the easiest to recycle

thermoplastics

which polymer type is the most brittle

thermoset

which type of polymer can deform the most without breaking

elastomers

the most common semiconductor is

silicon

at the same temperature, the spacing between atoms in AL2O3 is the same in the US as it is in Australia

true

the equilibrium spacing between atoms in a solid is the same at all temperatures

false

it takes a force to move atoms in solids away from their equilibrium positions

true

primary bonds are stronger than secondary bonds

true

the primary bonding type that involves the transfer of electrons to form positive and negative ions is

ionic bonding

the primary bonding type that involves sharing of electrons that are not free to move is

covalent bonding

the type of bonding that occurs where valence electrons flow freely is

metallic bonding

the type of bonding that occurs mostly in metals is

metallic bonding

the type of bonding that occurs mostly in ceramics is

covalent, ionic or a mix of the two

the type of bonding that occurs mostly in semiconductors is

covalent bonding

the type of bonding that occurs mostly in thermoplastic is

covalent + secondary bonding

the strength of an elastomer can be increased by

increasing the number of covalent bonds

covalent bonds are not directional

fasle

the bonding energy for MgO is 1000 kj/mole. the bonding energy for tungsten is 849 kj/mole. which of the two would you predict would have a higher melting point?

MgO

the bonding energy fir MgO is 1000 kj/mole. the bonding energy for tungsten is 849 kj/mole. which of the two would you predict would have a higher stiffness?

MgO

the same compound can form a crystalline or an amorphous structure

true

atoms in solids are not at their equilibrium position near defects

true

the number of vacancies in a solid decreases as temperature increases

false

a substitutional solid solution is more likely to occur when the minor element atom (solute) is small relative to the major element atom (solvent)

false

an interstitial solid solution is more likely to occur when the minor element atom is small relative to the major element atom

true

defects affect the properties of materials

true

permanent deformation to a material when loaded is called

plastic deformation

if plastic deformation is difficult, ductility is lower

true

the metal crystal structure with the highest ductility is

face centered cubic

the metal crystal structure with the lowest ductility is

hexagonal close pack

dislocation slip is easiest in which metallic crystal structure

face centered cubic

dislocation slip is easier in ceramics

false

which of the following is stronger

copper with 10 wt% zinc

which of the following is stronger

plastically deformed copper

which of the following is stronger

a single phase aluminum alloy

which of the following is stronger

pure copper with a small grain size

the number of vacancies increases with increasing temperature

true

dislocation slip occurs along random directions in crystal

false

plastic deformation occurs by bonds breaking and reforming

true

which of the following will be stronger

a thermoplastic rope that has been formed with plastic deformation.