FE Review - MatSci

What are the Miller Indicies for the plane shown in the cubic cell?

• (0 ½ 0)

• (0 2 0)

• (1 2 1)

• (∞ ½ ∞)

Answer explanation

1) Determine the intercept for each axes:

x: ∞

y: ½

z: ∞

2) Take the reciprocal:

x: 0

y: 2

z: 0

( 0 2 0)

The activation energy for aluminum in a copper solvent at 575°C is 1.6 x 10⁸ J/kmol. What is the diffusion coefficient, D, if the constant of proportionality, D₀, is 7 x 10⁻⁶ m²/s?

• 4.04 x 10⁻⁴⁷ m²/s

• 2.04 x 10⁻²⁰ m²/s

• 9.75 x 10⁻¹⁶ m²/s

• 2.31 x 10⁻⁵ m²/s

Answer explanation

A steel alloy contains 2.5% weight of carbon. What phase(s) is/are present at 900°C?

• Liquid

• γ + liquid

• γ + carbide

• α + carbide

Answer explanation

P 129

Order the microstructures from hardest (1) to softest (4):

• Ferrite

• Bainite

• Pearlite

• Martensite

A sample composed of 20% α begins to melt at what temperature?

• 825°C

• 1050°C

• 1500°C

• 1630°C

Answer explanation

A sample composed of 80% α is heated to 900°C, what is the precent of solid at this temperature?

• 25%

• 40%

• 60%

• 75%

Answer explanation

Why is aluminum more rust resistant that steel?

• The reaction rate with the atmospheric oxygen is higher for steel

• The reaction rate with the atmospheric oxygen is higher for aluminum

• Iron atoms are larger than aluminum atoms, and thus, the interstitial space is larger

• Iron has greater magnetic properties than aluminum

A 2in diameter rod of 4140 steel is quenched in water.  What is the approximate Hardness at the center of the bar.

• 58 HRC

• 54 HRC

• 49 HRC

• 31 HRC

Answer explanation

P 124 - 125

A 5cm diameter bridge tension member (rod) experiences a loading of 275 kN every time a car crosses the bridge. The average traffic on the bridge is 50 car/hr, and the bridge has a design life of 5 years. The S-N curves for several materials are shown. Strictly from the standpoint of fatigue, select the material(s) that the tension member could be constructed from if the bridge is to safely reach the end of its design life. Select all that apply.

• Steel

• Aluminum

• Copper

• Cast Iron

Answer explanation

What type of crystalline structure is shown?

• Simple Cubic

• Face Centered Cubic

• Hexagonal Close Packed

• Body Centered Cubic