Generic selectors
Exact matches only
Search in title
Search in content
Search in posts
Search in pages
Filter by Categories
nmims post
Objective Type Set
Online MCQ Assignment
Question Solution
Solved Question
Uncategorized

Analyze the following figure answer the following questions
materials-science-questions-answers-eutectic-systems-q1

1. What is the line that defines the solubility limit of A in B and B in A from the figure?
a) Solidus line
b) Liquidus line
c) Solvus line
d) Solidus line and Liquidus line

View Answer

Answer: c [Reason:] In addition to liquidus and solidus lines there are two more lines on A and B which define the solubility limits B in A and A in B respectively. These are called solvus lines.

2.Three phases (L+α+β) coexist at point E. This point is called _____
a) Peritectic point
b) Eutectic point
c) Eutectoid point
d) Eutectic point or composition

View Answer

Answer: d [Reason:] Three phases (L+α+β) coexist at point E. This point is called eutectic point or composition.

3. In hypoeutectic alloys micro structure at room temperature consists of________
a) Proeutectic β and α
b) Eutectic mixture (α+β)
c) Proeutectic β and eutectic mixture (α+β)
d) Proeutectic α and eutectic mixture (α+β)

View Answer

Answer: d [Reason:] In hypoeutectic alloys the αphase solidifies first and the microstructure at RT consists of this αphase (called proeutectic α) and the eutectic (α+β) mixture.

4.Why Pb-Sn eutectic alloys are used for soldering purpose?
a) The melting point at eutectic point is maximum
b) The melting point at the eutectic point isminimum
c) The melting point at the eutectic point is constant
d) The boiling point at the eutectic point is maximum

View Answer

Answer: b [Reason:] The melting point at the eutectic point is minimum. That’swhy Pb-Sn eutectic alloys are used as solders. Al-Cu, Al-Si, Ag-Cu are other eutectic systems.

From the figure answer the following questions
materials-science-questions-answers-eutectic-systems-q5

5. Crystals of which material begin to form at point a from the figure?
a) Crystals of proeutectic α
b) Crystals of proeutectic β
c) Crystals of eutectic (α+β)
d) Crystals of proeutectic α and β

View Answer

Answer: a [Reason:] While cooling a hypoeutectic alloy which is in liquid state, the temperature drops continuously till liquidus point, a, at which crystals of proeutectic αbegins to form.

6. At any point b, the αfraction is given by the lever rule as
________
a) mn/bn
b) bn/mn
c) ab/be
d) be/ab

View Answer

Answer: b [Reason:] On further cooling the fraction of αincreases. At any point, b, in the two-phase region the αfraction is given by the lever ruleas bn/mn.

Analyze the following figure and answer the following
materials-science-questions-answers-eutectic-systems-q7

7. The inflection in the cooling curve between points a and e is due to _________
a) Latent heat
b) Low temperature
c) High temperature
d) Specific heat

View Answer

Answer: a [Reason:] Solidification of proeutectic αcontinues till the eutectic temperature is attained. The inflection in the curve between points a ande is due to latent heat.

8. At the eutectic point (e) the eutectic reaction proceeds at a constant temperature as ________
a) F = 1
b) F = 0
c) F = 2
d) F = 3

View Answer

Answer: b [Reason:] At the eutectic point the solidification of eutectic mixture (α+β) begins through the eutectic reaction which proceeds at a constant temperature as F = 0 (2– 3+ 1).

9. Any composition left of point cor right of point dwill cool and solidify like a _______
a) Eutectic
b) Proeutectic
c) Eutectoid
d) Isomorphous system

View Answer

Answer: d [Reason:] Any composition left of point c or right of point d (α and β single phase region respectively) will cool and solidifies like anisomorphous system.

10. A 34.6% Pb-Sn alloy is cooled just below the eutectic temperature (183°C). What is the fraction of proeutectic α and eutectic mixture (α+β)?
a) 70% and 30%
b) 64% and 36%
c) 36% and64%
d) 30% and 70%

View Answer

Answer: b [Reason:] The eutectic point is at 61.9% Sn and α boundary is at 19.2% Sn. Apply the lever rule % proeutectic α= 100*(61.9 – 34.6)/(61.9 – 19.2) = 64% % (α + β) = 100* (34.6 – 19.2)/(61.9 – 19.2) = 36%.

Synopsis and Project Report

You can buy synopsis and project from distpub.com. Just visit https://distpub.com/product-category/projects/ and buy your university/institute project from distpub.com