Materials Science: 10 Things Every Engineer Should Know: Final

A powerful use of the Arrhenius relationship is to measure creep data at high temperatures over conveniently short time periods and then extrapolate the data to __________ temperatures, allowing us to predict the performance of the material over long operating times.

low

Consider the body of an automobile made of steel. A small dent in that structure when the automobile is accidentally driven into a barrier is an example of _________ deformation.

palstic

Beyond the tensile strength (T.S.), the maximum stress value measured over the range of the tensile test, we measure the ductility corresponding to the total amount of ______________ deformation.

plastic

Body-centered cubic (bcc) alloys tend to exhibit the ductile-to-brittle transition because they have fewer slip systems than in the ductile face-centered cubic (fcc) alloys.

False

In the face centered cubic structure of aluminum, solid-state diffusion occurs by individual aluminum atoms hopping into adjacent interstitial sites.

False

A metal alloy known to have good ductility is used in the manufacture of a spring in a garage door assembly. The spring breaks catastrophically after 10 years of regular use, under a load known to correspond to about one half of the alloy's yield strength. This is a good example of fatigue failure.

True

In the tensile test, the yield strength (Y.S.) is found just beyond the linear elastic region (which gives the elastic modulus, E) at an offset of 0.2% strain.

True

In illustrating the relationship between atomic structure and the elastic modulus or stiffness of a metal (structure leads to properties!), we saw how elastic deformation follows from the stretching of atomic ___________.

bonds

For high temperature creep deformation in metal alloys, a common mechanism that we illustrated is ______________.

dislocation climb

Phase diagrams are maps that help us track microstructural development during the slow cooling of an alloy. The Fe-Fe3C (iron carbide) phase diagram is an example of a ______________ diagram, with special relevance to steelmaking.

eutectoid

The design plot monitors stress as a function of ______________.

flaw size

The relationship of fatigue to the design plot (introduced in our discussion of fracture toughness) is that we grow the size of a flaw at a relatively low stress until the flaw size reaches the ______________ segment of the design plot.

flaw-induced fracture

The design plot is composed of two intersecting segments: yield strength corresponding to ___________ and fracture toughness corresponding to flaw-induced fracture.

general yielding

The first three categories introduced in the opening of the course (metals, polymers, and ceramics) are based on the three types of primary bonding: metallic, covalent, and ____________, respectively.

iconic

Quenching a eutectoid steel below about 200 °C initiates the formation of martensite because the _______________ the austenite phase has become too great.

instability of

Combining the extrinsic behavior with the intrinsic on the Arrhenius plot produces a stable level of conductivity at ______________ temperatures.

intermediate

Electronic conduction in an _____________ semiconductor is the result of the promotion of an electron from the valence band up to the conduction band across an energy band gap.

intrinsic

___________________ is a linear defect with the Burgers vector perpendicular to the dislocation line.

An edge dislocation

The _________ plot is a linear set of data points in which the logarithm of rate is plotted against the inverse of absolute temperature in K-1.

Arrhenius

The impact energy is the standard property for monitoring the ductile-to-brittle transition. The impact energy is commonly measured by means of the ______________.

Crarpy test