Test 1-3 Multiple Choice

As a result of a decrease in grain size, the other features unchanged, the strength of metals will a. increase b. decrease c. not change

Increase

In metals restricting dislocation motion leads to a. increased hardness b. decreased strength c. both "a" and "b"

Increased hardness

The atomic radii of iron and carbon are 0.124 and 0.071 nm respectively. What kind of solid solubility is expected when these elements are mixed? a. Interstitial b. Substitutional c. both, "a" and "b"

Interstitial

Substances in which measured properties depend on the direction of measurement are called a. isotropic b. isomorphous c. anisotropic

Isotropic

With respect to mechanical properties, we expect a fine-grained polycrystalline copper, with random orientation of crystals, to be a. anisotropic b. isotropic c. polymorphic

Isotropic

Poisson's ratio in tensile testing of metals is the negative ratio between a. lateral an axial strains b. lateral and axial stresses c. lateral and axial deformations

Lateral an axial strains

Dislocation density is the total dislocation a. points per unit length b. length per unit volume c. area per unit volume

Length per unit volume

In Charpy impact testing of metals, the following group show a more significant ductile-to-brittle transition. a. Low strength (FCC-HCP) metals b. High strength metals c. Low strength BCC steels

Low strength BCC steels

ASTM method to determine grain size of metals is used to quantify the following feature. a. atomic structure b. crystal structure c. microstructure

Microstructure

The structure of metals that shows the size and shape of crystals is called: a. microstructure b. crystal structure c. macrostructure

Microstructure

We have two pieces of pure copper, each one cubic inch in size. If one of the pieces is a single crystal and the other is polycrystalline, which of the following characteristics is different between the two? a. crystal structure b. microstructure c. dislocation density

Microstructure

The following feature cannot be determined using a binary phase diagram. a. amount of phases b. microstructure of phases c. composition of phases

Microstructure of phases

In solid-state diffusion, the diffusion flux is proportional to a. inverse of concentration gradient b. negative of concentration gradient c. neither "a", nor "b"

Negative of concentration

Grain size strengthening of metals will cause a decrease in the following property: a. Strength b. Toughness c. Neither "a" nor "b"

Neither "a" nor "b"

In an isomorphous phase diagram we can find the following information. a. eutectic transformation b. a stable two-phase (a+b region c. neither "a" nor "b"

Neither "a" nor "b"

As a result of cold working of metals the following property increases. a. Ductility b. Electrical conductivity c. neither "a", nor "b"

Neither "a", nor "b"

In the equation n = 2(G-1) used to determine ASTM grain size, n represents a. ASTM grain size b. total grains in a cubic inch c. neither "a", nor "b"

Neither "a", nor "b"

The initial elastic portion of stress-strain curve is a. linear for all materials. b. non-linear for some materials. c. non-linear for all materials.

Non-linear for some materials

2. An isomorphous phase diagram is a diagram in which the maximum number of solid phases is a. one b. two c. three

One

In steels the eutectoid micro constituent is called a. Ferrite b. austenite c. pearlite

Pearlite

In manufacturing of electrical copper wires after the process of wire drawing, they are heated to the following temperature to regain conductivity. a. grain growth b. recrystallization c. recovery

Recovery

In order to relieve residual stresses in a cold-worked material, without significantly changing the strength, we need to anneal the material to the following temperature: a. recovery b. recrystallization c. grain growth

Recovery

If a spring, which is under tensile (pulling) load, does not completely go back to its original shape after the load is removed, the following property of the spring is exceeded. a. Toughness b. Stiffness c. Resilience

Resilience

In x-ray diffraction of crystalline materials, the fundamental factor being determined is a. The distance between parallel directions of the crystal. b. The distance between parallel planes of the crystal. c. The angle between different crystallographic directions.

The distance between parallel planes of the crystal

During the recovery of a cold-worked material, a. Grains with high strains are replaced with new, unstrained grains. b. All of the internal strain energy is relieved. c. The electrical conductivity is recovered to its pre-cold-worked state.

The electrical conductivity is recovered to its pre-cold-worked state.

The change in rate of cooling to solidify a molten Cu-Ni alloy, will have the least effect on a. the liquidus temperature of the alloy b. the solidus temperature of the alloy c. the homogeneity of the solid

The solidus temperature of the alloy

The amount of energy required to break a standard test piece of a material is a measure of the material's following property: a. toughness b. stiffness c. strength

Toughness

The area under the stress-strain curve obtained as a result of a tensile test, is an indication of the materials following property a. ductility b. strength c. toughness

Toughness

The following type of fracture occurs when the fracture path is cutting through the crystals. a. Intergranular b. Transgranular c. Semi granular

Transgranular

During plastic deformation of polycrystalline metals below recrystallization temperature, there would be no change in a. dislocation density of crystals b. volume of crystals c. shape of the grains

Volume of crystals

In polymorphic transformation of a piece of iron if there is no change in the atomic size of iron, there is a change in a. density of metal b. volume of the piece c. both, "a" and "b"

Volume of the piece

Which of the following substances is a true molecular substance? a. Water (H2O) b. Salt (NaCl) c. both, "a" and "b"

Water (H2O)

As a result of plastic deformation, metals become stronger. This strengthening mechanism is called: a. solid solution strengthening b. work hardening c. grain size strengthening

Work hardening

Which of the following mechanical properties is a better indication of the material's resistance to plastic deformation? a. Yield Strength b. Stiffness c. Ductility

Yield Strength

In creep testing of metals the constant stress acting on the material should be lower than a. tensile strength b. yield strength c. endurance limit

Yield strength

The following property is used to determine the "ease" of permanent bending in a forming operation. a. Yield strength b. Ductility c. Toughness

Yield strength

Polymorphic transformation can take place in the following type of materials: a. crystalline b. amorphous c. both, "a" and "b"

crystalline

As the temperature of a material decreases, the diffusion coefficient a. increase b. remains the same c. decreases

decreases

Young's modulus is a quantitative measure of the following property of materials: a. strength. b. toughness. c. neither "a" nor "b".

neither "a" nor "b".

When a heavily cold-worked metal is heated to its recovery temperature, its grain size will a. increase b. decrease c. not change

not change

In weight carrying applications, metals are used in the following form. a. amorphous b. single crystal c. polycrystalline

polycrystalline

If we hang 100 pounds to each of the two springs of exact same shape and geometry, made from materials A and B, and observe 1 inch elastic stretch in A and 1.5 inches elastic stretch in B, we can say which material is: a. stronger b. tougher c. stiffer

stiffer

The magnitude of diffusion coefficient depends on a. time b. temperature c. both, "a" and "b"

temperature

Knowing that Aluminum and Lead both have FCC crystal structures and lead atoms are larger than aluminum atoms, the atomic packing factor is greater for a. Pb b. Al c. the same for Pb and Al

the same for Pb and Al

Hall-Petch relationship is used to estimate the following property, based on grain size. a. yield strength b. stiffness c. ductility

yield strength

Stress concentration factor in mechanical component depends on: a. applied stress b. shape and size of discontinuity c. both, "a" and "b"

Shape and size of discontinuity

If we keep adding equal loads to both of the spring in the previous question and they each break at the same150 pounds load without plastic deformation, which of the two would be more resilient? a. Spring A b. Spring B c. need more information for this comparison.

Spring B

In solid-state diffusion, if there is no net accumulation or depletion of diffusing species, the diffusion is a. steady state b. non-steady state c. not possible

Steady state

A practical application for the eutectoid 3-phase transformation of steels is in a. steel casting b. cast iron casting c. steel heat treatment

Steel heat treatment

Which of the following terms is synonymous with cold working? a. Grain size strengthening b. Solid solution strengthening c. Strain hardening

Strain hardening

Hardness testing is a fast method providing some idea about material's following property: a. Stiffness b. Toughness c. Strength

Strength

Hot working of metals makes it possible to shape the metal with less force. This is due to the effect of heat on the following property. a. toughness b. strength c. ductility

Strength

Compared to room temperature properties, when metals are heated their a. strength and ductility both increase b. strength decreases but ductility increases c. ductility and strength both decrease

Strength decreases but ductility increases

The following characteristic is a dependent on the applied stress on the material. a. Stress intensity factor b. Fracture toughness c. Stress concentration Factor

Stress intensity factor

In the following type of solid solution the sizes of solute and solvent atoms are close to each other. a. substitutional b. interstitial c. immiscible

Substitutional

The atomic radii of copper and nickel are 0.128 and 0.125 nm respectively. What kind of solid solubility is expected when these elements are mixed? a. Interstitial b. Substitutional c. both, "a" and "b"

Substitutional

In steady state diffusion, diffusion flux depends on a. time b. temperature c. both, "a" and "b"

Temperature

The local plastic deformation of a tensile specimen of a ductile metal, known as necking, begins at the point corresponding to the material's: a. yield strength b. tensile strength c. fracture strength

Tensile strength

Using the Fe-Fe3C phase diagram shown in section 3 of this exam, if the microstructure of a steel consist of 78 weight % pearlite and 22 weight % Proeutectoid ferrite, the steel's composition is closest to: a. 2%C b. 0.76%C c. 0.6%C

0.6%C

In an FCC crystals the planar density of atoms is greater for the following crystallographic plane. a. (100) b. (111) c. (100) and (111) have the same PD

111

Using the Fe-Fe3C phase diagram shown in section 3 of this exam, if you slowly cool some molten cast iron containing 2.5%C, the temperature at which it completes solidification is closest to: a. 1490°C b. 1147°C c. 727°C

1147°C

Using the equation n = 2(G-1), for a microstructure with an ASTM grain size of 6, the number of grains counted in a 2 inch by 3 inch picture taken at a magnification of 400X would be closest to: a. 12 b. 32 c. 48

12

Using the Fe-Fe3C phase diagram shown in section 3 of this exam, if you slowly cool some eutectoid molten steel, the temperature at which it starts to solidify is closest to: a. 1490°C b. 1147°C c. 727°C

1490°C

Using the Fe-Fe3C phase diagram shown in section 3 of this exam, if you slowly cool some molten steel containing 0.4%C, the amount of pearlite at room temperature would be closest to: a. 100% b. 50% c. 40%

50%

Components under impact loading, made from BCC metals should be used at temperatures a. below ductile-to-brittle transition range b. above ductile-to-brittle transition range c. in the ductile-to-brittle transition range

Above ductile-to-brittle transition range

Knowing that Aluminumand Lead both have FCC crystal structures and lead atoms are larger than aluminum atoms, the linear density of atoms in [111] direction is greater for a. Pb b. Al c. the same for Pb and Al

Al

Which of the following is a line imperfection in a crystal? a. a twin boundary b. a grain boundary c. an edge dislocation

An edge dislocation

As impurity concentration in a solid solution increases, there is usually a. an increase in ductility and a decease in strength. b. an increase in strength and a decrease in ductility. c. an increase in both, strength and ductility.

An increase in strength and a decrease in ductility.

In grain size strengthening, the goal is to make the crystal sizes a. as small as possible b. as larger as possible c. just larger than before

As small as possible

The fraction of the volume of a solid piece of metal that is occupied by atoms is called: a. atomic packing factor b. density c. specific volume

Atomic packing

Comparing the following phases in steels, which one has the lowest strength? a. ferrite b. austenite c. cementite

Austenite

At the same temperature, carbon diffuses faster in the following polymorph of iron. a. FCC b. BCC c. HCP

BCC

Which of the following features on the fatigue fracture is visible to the naked eye and does not needs electron microscope to observe? a. Fatigue striations b. Beach marks c. Both need microscope to observe

Beach marks

If ASTM grain size of material A is greater than that of material B, the average size of the grains would be a. bigger in material A b. bigger in material B c. difficult to compare

Bigger in material

The following factor is effective on the recrystallization temperature of cold worked metals. a. Amount of cold work b. solid solution concentration c. both "a" and "b"

Both "a" and "b"

In a Charpy impact test, as a result of an increase in the test temperature, we expect to see an increase in: a. Impact energy b. Shear fracture c. Both, "a" and "b"

Both, "a" and "b"

The conditions for unlimited solid solubility of two metals in each other include the following. a. atomic size b. electronegativity factor c. both, "a" and "b"

Both, "a" and "b"

A binary phase diagram is a diagram consisting of two a. components b. phases c. microstructures

Components

Lever rule in phase diagrams is not needed to determine the following feature. a. composition of the phases b. mass fraction of the phases c. needed for both, "a" and "b"

Composition of the phases

X-ray diffractometry is a technique used for determining a. crystal structures b. crystal defects c. dislocation density

Crystal defects

As a result of a congruent transformation, we do not expect a change in material's a. composition b. volume c. crystal structure

Crystal structure

The structure of metals that shows the orderly repeated positioning of atoms in metals is called: a. microstructure b. crystal structure c. atomic structure

Crystal structure

What feature is most definitely different when comparing BCC iron with FCC iron? a. atomic structure b. crystal structure c. microstructure

Crystal structure

A material that has a long-range order in the location of its atoms/ions is called a. crystalline b. amorphous c. both, "a" and "b"

Crystalline

The main difference between adjacent crystals in a polycrystalline pure metal is in their a. crystallographic orientation b. crystal structure c. both, "a" and "b"

Crystallographic orientation

As a result of an increase in the amount of cold work, the recrystallization temperature will a. increase b. decrease c. not change

Decrease

When a heavily cold-worked metal is heated to its recrystallization temperature, its grain size will a. increase b. decrease c. not change

Decrease

By adding Cu to Ni we can make alloys that are stronger than pure Ni. This is because: a. pure copper is stronger than pure nickel. b. dissolved atoms facilitate dislocation movement. c. dissolved atoms act as obstacles in dislocation movement.

Dissolved atoms act as obstacles in dislocation movement.

Poisson's ratio in tensile testing of metals is used for calculations in the following type of deformation. a. plastic b. elastic c. both, a and b

Elastic

The stress amplitude below which a steel specimen will not fail in a fatigue test is called: a. fatigue life b. fatigue strength c. endurance limit

Endurance limit

Which of the following features on the fatigue fracture corresponds to the advance of a fatigue crack during a single load cycle? a. Fatigue striations b. Beach marks c. Both correspond to a single load cycle

Fatigue striations

In the following type of test we are measuring the number of cycles to failure. a. Fatigue test b. Creep Test c. Both, "a" and "b"

Fatigue test

In fatigue testing of the following type of materials you expect to see an endurance (fatigue) limit: a. Non-ferrous alloys b. Ferrous alloys c. Titanium alloys

Ferrous alloys

Carburizing steel containing 0.1%C at a constant temperature and an environment with a fixed carbon concentration would obey a. Fick's first law (steady state) b. Fick's second law (Non-steady state) c. neither "a", nor "b"

Fick's second law (Non-steady state)

The main difference in the microstructure of a cold worked brass, before and after recrystallization is its a. grain size b. crystal structure c. both, "a" and "b"

Grain size

As a result of cold working and recrystallization of an annealed metal, it is expected to be harder in recrystallized condition than before cold working. This strengthening mechanism is called: a. cold working b. work hardening c. grain size strengthening

Grain size strengthening

Using the following strengthening mechanism, strength can be increased without a loss in toughness. a. solid solution strengthening b. work hardening c. grain size strengthening

Grain size strengthening