Materials Science Quiz

Arrange the following structures according to increasing atomic packing factor (APF): a) crystalline body-centered cubic (b.c.c.) b) crystalline face-centered cubic (f.c.c.) c) crystalline hexagonal close-packed (h.c.p.) d) amorphous

Brittlement of the ceramic materials is the effect of their:

• strong atomic bonds

• amorphous structure

• lack of dislocations

• high resistance to dislocations movements

Hook's law: is valid for:

• very high strains

• very low strains

• any strains

• tensile strain only

The most frequently used materials have:

• monocrystalline structure

• polycrystalline structure

• amorphous structure

• heavy cross-linked structure

Which diffusion of atoms is quicker:

• volume diffusion

• gross boundary diffusion

• The diffusion: increase with increasing temperature

• The diffusion:decrease with increasing temperature

The strength of polycrystalline can be increased by:

• decreasing of grain size

• increasing of grain size

• making easier of the dislocation movement

• making harder of the dislocation movement

Composites are:

• inorganic glasses

• combination of two or more types of materials

• covalent cross-linked polymers

• two or more phase metals

Plastic deformation of crystalline materials is easier when:

• they haven't any dislocations

• they contain a few dislocations

• they contain very many dislocations

The overcooling (the difference between melting point and the cooling temperature) during crystallization of th(…) forming of:

• the coarse (big grain size) microstructure

• the fine (small grain size) microstructure

• has no influence on the microstructure

The Gibbs rule (at atm. pressure F=C-P+1) allows degrees of freedom calculation for known:

• components number and tempterature value

• phases and components. numbers

• structural elements and phases numbers

• components, phases and structural elements numbers