MSE 250 Exam 4

Phase diagrams can be used to identify alloys that are eligible for __.

c. age hardening

..Certain metal alloys can be strengthened using __ and __.

a. supersaturation; precipitation

We can use phase diagrams and __ graphs to predict the effects of __ and __ on the strength of age-hardened alloys.

b. strength vs. time; temperature; time

Why do blacksmiths dip hot metal objects in water? To __ them, in order to __ them.

b. quench; strengthen

We can obtain different __ by cooling steel at different __.

d. microstructures; rates

Nucleation and crystal growth are affected by quench __ and cooling __.

a. temperature; rates

We can control the strength of a steel part by manipulating its __ of __.

c. rate; cooling

Martensite is caused by a change in __, not by __ of carbon.

e. crystal structure; diffusion

Aluminum can be age hardened by adding 0.5% of Mg and 4% of __, and quenching it from a temperature of __ degrees C, and then letting it age over __.

a. Cu; 520; 24 hours

The first aerospace aluminum alloy, used in the Wright airplane crankcase, used __ hardening to strengthen the alloy

c. precipitation

Phase diagrams of age-hardenable alloys must show __ solid-solubility with __ temperature.

d. decreasing; decreasing

The strength of an age-hardened alloy __ with increasing ageing time at temperature, then reaches a __, and then __ after that.

a. increases; maximum; decreases

The hardness of an age-hardened alloy __ with increasing ageing time at temperature, then reaches a __, and then __ after that.

a. increases; maximum; decreases

An age-hardening alloy starts off as a __ before it age-hardens over time.

d. supersaturated solid-solution

After a short period of ageing at temperature, an age-hardened alloy is underaged, and has __ and __ precipitates.

e. small; underdeveloped

After an optimum period of ageing at temperature, an age-hardened alloy is peak-aged, and has __ and __ precipitates for strengthening of the alloy.

b. the optimum size; distribution of

After too long of a period of ageing at temperature, an age-hardened alloy is over-aged, and experience __ of precipitates.

a. coarsening

Age hardened alloys can be used for bicycle __, __ cookware, and __ in integrated circuit chips.

b. frames; metal; metal interconnects

Precipitation hardening works by a mechanism where __ impede __.

a. precipitate; dislocation motion

Precipitation hardening is used in the __ system.

b. Al-Cu

Precipitation hardening is used in the __ system.

c. Mg-Al

The first phase of precipitation hardening of Al-Cu is to __ the alloy to form a __.

c. solution heat-treat; single-phase solid-solution

The second phase of precipitation hardening of Al-Cu is to __ the alloy to __.

b. quench; room-temperature

The third phase precipitation hardening of Al-Cu is to __ the alloy to __ and __ small __ precipitates within the Al matrix.

c. reheat; nucleate; grow; theta-phase

During precipitation hardening of Al-Cu, the strength of the alloy __ as the precipitates __ and initially __ in size, until they reach __.

b. increases; nucleate; grow larger; an optimum size

During precipitation hardening of Al-Cu, the hardness of the alloy __ as the precipitates __ and initially __ in size, until they reach __.

a. increases; nucleate; grow; an optimum size

During precipitation hardening of Al-Cu, the strength of the alloy __ as the precipitates __ beyond the __.

c. decreases a bit; coarsens; optimum size

During precipitation hardening of Al-Cu, the hardness of the alloy __ as the precipitates __ beyond the __.

c. decreases a bit; coarsens; optimum size

An Al-Cu alloy with a small wt% Cu, develops theta-double-prime phase regions when it is heat-treated. This phase is __ and __ with the alpha-phase lattice.

a. disordered; coherent

The theta- double prime phase creates __ strain fields in the Aluminum matrix

b. large

Upon further heat-treatment, the theta phase forms in the Al-Cu alloy. The theta phase is __ and __ with the aluminum lattice.

b. ordered; incoherent

The incoherent theta phase in an Al-Cu alloy has misfit __ that provide __ around the particle.

d. dislocations; strain relief

An incoherent boundary (between a precipitate and the matrix around it) has misfit __ in the boundary.

e. dislocations

A coherent boundary (between a precipitate and the matrix around it) has __ dislocations.

d. no misfit

Precipitate hardening occurs by formation of __ dispersed __.

b. finely; precipitates

Al-Mg alloys are __ hardenable.

b. precipitation

Precipitation hardening typically uses a __ step heat-treatment process to accomplish the hardening.

a. 3

The first step in precipitation hardening is to __ to form a __.

a. solution-treat; single-phase

The second step is precipitation hardening is to __ to form a __ alloy.

b. quench rapidly; supersaturated single-phase

The third step in precipitation hardening is to __ the alloy at __ temperature or at __ temperature.

c. age; an intermediate; room

Aging an alloy at an intermediate temperature is called __ ageing.

d. artificial

Aging an alloy at room temperature is called __ ageing.

e. natural

Aging an alloy at __ is called natural ageing.

c. room temperature

Non-ferrous alloys such as __, __, __, __ alloys can be precipitate hardened.

c. Cu; Al; Ti; Mg

Phase diagrams can be used to identify alloys eligible for __.

a. age hardening

Certain metal alloys can be __ using __ and __.

e. strengthened; supersaturation; precipitation

Age-hardening can change the __ of an alloy and thereby contribute to its hardening.

c. microstructure

Phase diagrams and __ vs __ graphs can be used to predict the optimum __ and __ for the strongest age-hardened alloys.

b. strength; anneal-time; temperature; time

Age hardening can also be called __ hardening.

c. precipitation

Age hardening is a method of __ metals to __ properties.

a. heat-treating; optimize

Age hardening is a method of __ strengthening.

b. dispersion

Age hardening usually increases the __ of the alloy.

b. strength

Age hardening usually increases the __ of the alloy.

a. toughness

Age hardening is typically performed in __ steps.

b. 3

During solution treatment, an alloy is heated __ the __ temperature to dissolve __ to form a __ single-phase structure.

c. above; solvus; second-phase particles; homogenous

During quenching, the alloy is __ cooled to __ temperature from __ temperature single-phase __ region to form a __ solid-solution in the __ region of the phase diagram.

d. rapidly; room; a high; solid-solution; supersaturated; 2-phase

During natural ageing, __ form at __ temperature, to provide __ strengthening.

c. precipitates; room; optimum

During artificial ageing, __ form __ room temperature, but below the __ temperature, to provide __ strengthening.

b. precipitates; above; solvus; precipitate

The higher the temperature of the ageing of an alloy, the __ the spacing of the __. This then affects the __ of the alloy.

d. wider; precipitates; strength

The Wright Flyer crankcase, was the first known use of __.

b. precipitation hardening

The physical characteristics, properties and applications of polymers are __ those of metals and ceramics.

b. different from

There are __ major synthesis methods are making polymers.

b. 2

The major synthesis methods for making polymers are __ polymerization and __ polymerization.

a. addition; condensation

Addition and condensation polymers have __ chemical structures.

b. different

There are __ major morphologies among polymers.

c. 4

The __ and __ characteristics of polymers impact their mechanical properties.

c. structure; thermal

The different types of polymer __ affect how they are __ to make products.

b. structures; processed

The different types of polymer __ affect their potential for __.

c. structures; recycling

Common polymers are typically __, with __ elastic modulus.

d. lightweight; low

Common polymers typically have __ strength, __ that of metals and ceramics.

a. low; <10%

Most polymers are __, but some are __.

c. ductile; brittle

Polymers are often used for __ products that are __ produced.

b. common; mass

Polymers have __ melting temperatures.

c. low

Engineering structural polymers can be __ or __.

d. reinforced; unreinforced

Natural polymers include __ and __ products.

c. trees; wood

Rubber is an example of __ polymer.

a. a natural

A term polymer consists of the terms poly = __, and mer = __.

c. many; units

In polyethylene, the repeat unit is __.

b. -CH2-CH2-

In poly(vinyl-chloride), the repeat unit is __.

d. -CH2-CHCl-

In polypropylene, the repeat unit is __.

d. -CH2-CHCH3-

Polyethylene is commonly used for the manufacture of __.

b. plastic bottles

Polyvinylchloride (PVC) is commonly used for manufacture of __.

d. water pipes

Polypropylene is commonly used for the manufacture of __.

d. plastic ropes

Polymers typically have ___ bonds along the polymer-chain backbone.

c. covalent

Polymers typically have __ bonds between the polymer-chains.

b. Van der Waals

C-C __ causes the polymer-molecule to adopt a __ string-like shape.

c. rotations; loosely coiled

The C-C bonds in simple polymers form angles of __ degrees.

c. 109

Polymers are often classified based on __, __ and __.

c. structure; morphology; application

Polymers can be __ or __.

a. synthetic; natural

Wood is a __ polymer, made of __.

b. natural; cellulose

Synthetic polymers can be __, __ and __ or __.

c. thermoplastic; thermosetting; coatings; adhesives

Rubber cement is a ___ polymer that can be used as a ___ or ___.

d. synthetic; coating; adhesive

Thermoplastic polymers are __ and __ in structure.

a. linear; 1D

Thermosetting polymers are __ and __ in structure.

b. nonlinear; 3D

Thermosetting polymers are __ and __.

c. heat-setting; cross-linked

Rubber is a __.

d. cross-linked elastomer

Thermosetting polymers can be __, __ or crosslinked.

a. lightly; moderately; heavily

Lightly crosslinked polymers are used for rubber __.

b. bands

Rubber ties are made of __ crosslinked polymers.

a. moderately

Rubber shoe soles are made of __ crosslinked polymers.

a. moderately