NCEES Materials Science 3

Question 1

The Charpy impact test is used to measure a material's:

Accepted Answer

Notch toughness

Answer

The Charpy test measures impact energy absorbed by a notched specimen, characterizing the material's notch toughness and susceptibility to brittle fracture.

Question 2

Austenite in steel is the FCC phase stable above approximately:

Accepted Answer

727°C

Answer

For plain-carbon steels, austenite (FCC iron) becomes stable above the eutectoid temperature of approximately 727°C (A1 line on the Fe-C diagram).

Question 3

Which process involves heating steel above the critical temperature and then cooling it in still air?

Accepted Answer

Normalizing

Answer

Normalizing consists of austenitizing steel and allowing it to air-cool, producing a finer, more uniform pearlitic microstructure than full annealing.

Question 4

Galvanic corrosion occurs when two dissimilar metals are in electrical contact in the presence of an electrolyte. Which metal corrodes preferentially?

Accepted Answer

The more active (anodic) metal

Answer

In a galvanic couple, the more active (less noble) metal acts as the anode and undergoes preferential oxidation and corrosion.

Question 5

The glass transition temperature (Tg) of a polymer is the temperature at which:

Accepted Answer

The amorphous regions transition from glassy to rubbery behavior

Answer

At Tg, the amorphous phase of a polymer transitions from a rigid, glassy state to a soft, rubbery state as chain mobility increases.

NCEES Practice Test

NCEES Practice Test

NCEES Materials Science 3