Met Test Final Exam 1

A series of these tests are used to compile a stress-rupture diagram. a. Tensile test b. Impact test c. Fatigue test d. Creep test

D

From tensile test date, this property is computed as (A₀-A₁)/A₀ x 100% a. Percent elongation b. The ultimate tensile strength c. Modulus of elasticity d. Percent reduction in area

D

This type of bonding is considered the weakest of the four types listed below a. Metallic b. Ionic c. Covalent d. VanderWaals

D

Which of these crystalline defects is not classified as a point defect? a. Frenkel Defect b. Interstitial c. Vacancy d. Grain Boundary

D

A material with an ASTM grain size of 8 would have _______ crystals compared to one of ASTM 2, and would also be ______. a. Smaller, weaker b. Smaller, stronger c. Larger, weaker d. Larger, stronger

B

According to Schmid's Law (ι=σcosλcosθ), the most favorable condition for slip to occur is: a. λ= 90° b. λ= 45° c. θ= 90°

B

Copper atoms are about the same size as nickel atoms. We would expect copper atoms to move in nickel by: a. Interstitial diffusion b. Vacancy diffusion

B

Deformation or ductility in a metal is the result of movement of this type of defect. a. Vacancy b. Dislocations c. Interstitials d. Grain Boundary

B

During a tensile test, this is the highest value attained by the engineering stress: a. Percent elongation b. The ultimate tensile strength c. Yield point or yield strength d. Modulus of elasticity

B

In Fick's First Law, J= -Ddc/dx, the term "D" represents: a. The flux of atoms (# crossing an area in a given time) b. The diffusion coefficient c. The temperature d. The concentration gradient

B

In the body-centered cubic (BCC) crystal structure, atoms touch (are in contact) along the: a. Cube edges b. Body diagonals c. Face diagonals

B

Line imperfections in a crystalline solid are called: a. Vacancies b. Dislocations c. Interstitials d. Grain Boundaries

B

Many ceramic and powder metallurgy products are made by pressing solid particles to a desired shape and then heating the compared material so diffusion can bond the particles to one another. This process is called: a. Diffusion bonding b. Sintering c. Creep d. Activation

B

Materials that can exist in more than one crystal structure (depending upon the conditions of temperature and pressure) are called: a. Amorphous b. Polymorphic c. Anisotropic

B

Materials with this structure have four non-parallel, close-packed, slip planes {111} with three slip directions in each for a total of 123 independent slip systems. The result is exceptional ductility. a. BCC b. FCC c. HCP

B

The coordination number for a body-centered cubic (BCC) structure is: a. 6 b. 8 c. 12 d. 14

B

The directions of atom-touching in the FCC structure have the Miller Indices form of: a. <100> b. <110> c. <111> d. <000>

B

The number of "nearest neighbor" atoms in a crystal structure is called the: a. Miller Index b. Coordination Number c. Packing factor d. Unit cell

B

The stacking sequence of close-packed planes in the face-centered cubic (FCC) crystal structure is: a. ABABAB b. ABCABC c. there are no close packed planes

B

This test can be used to determine if a metal has a ductile-to-brittle transition temperature. a. Tensile test b. Impact test c. Fatigue test d. Creep test

B

This type of bonding requires two different types of atoms (an electron donor and an electron receiver) a. Metallic b. Ionic c. Covalent d. VanderWaals

B

Two common types of this test are the Rockwell and Brinell tests. a. Tensile test b. Hardness test c. Fatigue test d. Creep test

B

Aluminum, copper and silver are typically soft, weak, and ductile materials. These are characteristics of which crystal structure? a. SC b. BCC c. FCC d. HCP

C

An interstitial point defect is: a. An atom missing from a lattice point b. An atom of one species occupying a lattice point in a lattice of another species c. An atom that is inserted into a crystal at a location that is not a lattice point

C

As plastic deformation occurs, most specimens are able to hold more load. For this to occur: a. The crystal structure must be changing to the stronger BCC structure b. The load-bearing area must be increasing c. The material must be getting stronger

C

As the temperature is increased in the range of atomic diffusion, we would expect the rate of atom movement to _____ with temperature. a. Increase linearly b. Decrease linearly c. Increase exponentially d. Decrease exponentially

C

Bonds of this type tend to be "directional", and the limited number of nearest neighbors often leads to light weight (low density) materials. a. Metallic b. Ionic c. Covalent d. VanderWaals

C

Compared to materials with other crystal structures, materials with the HCP structure tend to: a. Have greater strength b. Have greater ductility c. Be brittle

C

Engineering strain is defined as: a. Load/ original load b. Load/ actual load c. Stretch. original stretch d. Load/ stretch

C

The "ductility" of a material can be determined by which two tensile test properties? a. Young's modulus and tensile strength b. Tensile strength and elongation c. Elongation and reduction in area d. Elongation and Young's modulus

C

The endurance limit for steels can be determined by a series of the cyclic-loading tests. a. Tensile test b. Impact test c. Fatigue test d. Creep test

C

The majority of all mechanical component failures occur as a result of: a. Wear b. impact c. Fatigue d. Creep

C

The packing factor for structures involving stacked close-packed planes (highest possible) is: a. 52% b. 68% c. 74% d. 100%

C

The stiffness or rigidity of a material can be evaluated by this tensile test property: a. Yield Point b. Tensile strength c. Modulus of elasticity d. Percent elongation

C

This class of materials typically are hard and brittle, and have low electrical and thermal conductivity. a. Metals b. Polymers c. Ceramics

C

When we heat a material, we can estimate the temperature where diffusion becomes significant as: a. The melting point of the material b. 1000° c. 0.4 times the melting point in absolute temp. d. 0.2 times the melting point when expressed in Centigrade

C

Adding additional imperfections to a commercial metal (one that already contains defects) will almost always ______ the strength and ______ ductility. a. Increase, decrease b. Increase, increase c. Decrease, increase d. Decrease, decrease

A

All the tests done at Missouri S&T (then UMR) to investigate the brittleness of the hull plate steel from the HMS Titanic were: a. Impact test b. Fatigue test c. Creep test d. Hardness test

A

At a given elevated temperature, diffusion atoms would be easiest for atom movement: a. Along free surfaces b. Along grain boundaries c. Through grains (volume)

A

For most manufacturing items, we would like the applied stresses to always be below which tensile test value? a. Yield point or yield strength b. Modulus of elasticity c. Tensile strength d. Breaking strength

A

If we increase the temperature, we would expect the diffusion coefficient to: a. Increase b. Decrease c. Remain unchanged

A

Materials with this type of bonding have valence electrons that are free to "wander" throughout the structure (high conductivity) a. Metallic b. Ionic c. Covalent d. VanderWaals

A

The defect that occurs when an atom is missing from a lattice point is called a(n): a. Vacancy b. Interstitial c. Substitutional

A

The type pf defect responsible for the increased strength obtained during strain hardening (deformation strengthening) is the: a. Dislocation b. Grain Boundary c. Substitutional point defect

A

Which of the following crystal structures does NOT contain close-packed planes? a. BCC b. FCC c. HCP

A