Principles of Casting Technology- Week 1 content & Assignment SOLUTION

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For any phase transformation to take place, Gibbs free energy change should be_______

 Positive

 Zero

 Negative

 any value between 0 to 1

1 point

Which of the statement about the constitutional supercooling is correct?

 It is experienced predominantly in case of large freezing range alloys

 It is experienced predominantly in case of metals with constant freezing temperature

 It is experienced predominantly in case of small freezing range alloys

 It is the process of raising the temperature of melt above its melting point

1 point

Pure copper melts at 1084 oC. At 900oC, free energy of molten copper with respect to free energy of copper in solid state is

 Larger

 Smaller

 Equal

 None of the above

1 point

Which of the statement is correct for homogeneous nucleation?

Statement I: Foreign particles assist in nucleation.
Statement II: Probability of nucleation at all the sites in the domain is same

 Only statement I is correct

 Statement II is correct

 Both statement I and II is correct

 Both statement I and II is incorrect

1 point

Lower value of Centerline feeding resistance (CFR) indicates that the material is ____________.

 A large freezing range alloy and can be easily fed

 difficult to be fed into the mold

 easy to be fed into the mold

 of eutectic composition and very difficult to be fed in the mold

1 point

Which of the following statement is correct for the solidification of alloy:

 Solidification occurs over a temperature range.

 Solidification occurs at a constant temperature.

 Constitutional supercooling assists during the solidification process

 Both b and c are correct

1 point

Metal's ability to take on the shape of a casting cavity is made possible by utilizing which of the following material properties?

 Hardness

 Toughness

 Porosity

 Fluidity

1 point

According to the Chvorinov’s rule, solidification time of casting is proportional to the 

 Ratio of volume of casting to its surface area

 Square of the ratio of volume of casting to its surface area

 Square of the ratio of surface area of casting to its volume

 Ratio of surface area of casting to it volume

1 point

During the solidification process, the critical radius of nucleaion is determined by the relationship between the ________ term and the _________term.

 Surface energy, Volume energy

 Surface energy, surface area

 Volume energy, Mechanical energy

 Surface area of casting, Volume of casting

1 point

The diameter to height ratio of the mould is 1. If the solidification time is 2.0 minutes and the mould constant is 1956000 s/m2, the mold's dimensions will be

 D = H = 6.2 cm

 D = H = 2.6 cm

 D = H = 4.7 cm

 D = H = 7.4 cm

SOLUTION