Chapters 7-10

cast iron has a higher degree of ductility than aluminum

false

a failure in a cleavage is an example of a brittle failure

true

small crystals are formed in metal as a result to rapid cooling

true

a brittle material stretches considerably before failure occurs

false

a grain is also known as a crystal

true

there are nine total atoms in a body-centered cubic cell

true

a solid solution of steel containing less than 0.1% carbon at room temperature is know as cementite

false

ferrite is a mixture of pearlite and martensite

false

martensite is a harder structural from of steel than cementite

true

when a sample of low-carbon steel is viewed under a microscope, the pearlitic structures containing carbon generally appear much lighter than other portions of the steel

false

ferric structures in steel resemble white patches when viewed under a microscope

true

when preparing a sample of steel for microscopic viewing, the surface is etched with acid after it has been polished

true

which of the following steel structures has a needlelike appearance when viewed under a microscope?

martensite

which type of failure occurs when a zone within a crystal structure is deformed from its original orientation and two identical planes are formed on ether side of the zone

twining

which type of crystal structure in a metal is generally the most resistant to cracking

small grain

work hardening usually results in a loss of

ductility

what transformation occurs when austenitic iron is slowly cooled to the lower transformation temperature

the face-centered cubic structure changes to a body-centered cubic structure

which of the following is the first to develop during a formation of crystal when iron s cooled

unit cell

which space lattice structure is usually considered to be the most brittle

body-centered tetragonal

which of the following statements is not true of ferritic iron

it has a close-packed hexagonal space lattice structure

austenitic iron has ______ space lattice structure

face-centered cubic

when a sample of ferritic iron is heated above its upper transformation temperature and then cooled very slowly, the resulting structure is

ductile

what information about specific steels can be determined by referring to an iron-carbon phase diagram

the structures of steel that occur at various temperatures when the percentage of carbon is known

where do structures of 100% austenite primarily occur on an iron-carbon phase diagram

above the upper transformation temperature line

rough edges, square like, patchy (microstructural images of metal samples)

Austenite

dark in color, tiger stripes (microstructural images of metal samples)

almost all pearlite

white in color, hit of dark spots (microstructural images of metal samples)

ferrite-pearlite

needle like (microstructural images of metal samples)

martensite

Over 80% austenite with some ferrite (Look at the picture for the test)

F

all austenite (Look at the picture for the test)

A

over 80% ferrite with some austenite (Look at the picture for the test)

G

a combination of austenite, ferrite, and pearlite (Look at the picture for the test)

J

almost all ferrite (Look at the picture for the test)

C

half pearlite and half ferrite (Look at the picture for the test)

D

over 80% pearlite with some ferrite (Look at the picture for the test)

I

all pearlite (Look at the picture for the test)

B

over 80% pearlite with some cementite (Look at the picture for the test)

H

over 80% austenite with some cementite (Look at the picture for the test)

E

Which structural form of steel has a longer grain size, ferrite or martensite?

ferrite

approximately what percentage of carbon exists in a sample of pearlite at room temperature?

.890

when referring to an iron-carbon phase diagram, the ______ point is located at the intersection of the upper transformation temperature line, the lower transformation temperature line, and the pure pearlite line.

eutectoid

when pearlite and cementite are in the same steel structure, which has the darker appearance when viewed under a microscope?

pearlite

the repeated application and removal of force which causes hardening in a material is known as ______ or "cold working

work hardening

a slip band is a group of _____ that may form during a slip failure

slip planes

is the arrangement of atoms in a solidified crystal irregular or very orderly and precise?

very orderly and precise

which is usually stronger, a material with large grain size or small grain size?

small grain size