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Material Science and Metallurgy Question Paper - Dec 15 - Mechanical Engineering (Semester 3) - Jawaharlal Nehru Technological University (JNTUH)
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Material Science and Metallurgy - Dec 15
Mechanical Engineering (Semester 3)
Total marks: 75
Total time: 3 Hours
NOTE-
This question paper contains two parts A and B.
Part A is compulsory which carries 25 marks. Answer all questions in part A.
Part B consists of 5 units. Answer any one full question from each one unit.
Each question carries 10 marks and may have a,b,c, as sub questions.
PART-A
1.a.
Define the term composite material. What are natural composites? Give examples.
(2 marks)
00
1.b
Calculate the effective number of atoms in the HCP unit cells. Describe the basis for generating the HCP structure starting from the hexagonal space lattice.
(3 marks)
00
1.c.
What is level rule?
(2 marks)
00
1.d.
What is annealing?
(3 marks)
00
1.e.
What is carbon equivalent?
(2 marks)
00
1.f.
Give reason for extremely high hardness of martensite.
(3 marks)
00
1.g.
What is Temper-embrittlement phenomena?
(2 marks)
00
1 .h.
What is ASTM-grain size number? And what is importance?
(3 marks)
00
1.i.
What are the limitations of plain carbon Steels?
(2 marks)
00
1.j.
What is the effect of cobalt additions on hardenability?
(3 marks)
00
PART-B
2.a.
Discuss the necessity of alloying.
(3 marks)
00
2.b.
Determine the relationship between atomic radius and lattice parameter for FCC crystal. Find the lattice parameter and atomic structure of AI (FCC) having density 2700kg/cm³ and atomic weight of AI is 26.89.
(4 marks)
00
2.c.
Distinguish between intermetallic compound and interstitial compound
(3 marks)
00
OR
3.a.
What is the role of grain size on the properties of a material?
(3 marks)
00
3.b.
Discuss briefly the Hume-Rothery rules.
(4 marks)
00
3.c.
Discuss between interstitial solutions and sub-titutional solutions.
(3 marks)
00
4.a.
Two elements A and B arr completely suitable in the liquid state and are completely in soluble in the solid state. Theirs healthy temperature are 700 and 400°C respectively. They form an eutectic at A-70B and 250° C. Draw the phase diagram label various phases and temperature.
(5 marks)
00
4.b.
Discuss the phases present their volume and concentration at any two temperature for the alloy 70A-30B.
(5 marks)
00
OR
5.a.
Give the number if variables and the degree of freedom at the electric temperature of a binary phase diagram.
(4 marks)
00
5.b.
What is Tie-line rule?
(3 marks)
00
5.c.
What is coring and how it can be minimised?
(3 marks)
00
6.a.
Compare the characteristics of nucleation growth transformation of austenite with that of the diffusion less transformation.
(5 marks)
00
6.b.
What is retained Austenite and how it can be minimised?
(5 marks)
00
OR
7.a.
What is the effect of alloying elements on:
(5 marks)
00
i) Eutectiod temperature.
ii) Eutectiod composition.
iii) critical cooling rate.
iv) Formation of cardibe.
v) Asutenite phase regions.
vi) gas content.
vii) Intermediate phase formed in steel.
7.b.
What is the spheroidizing Annaeling and normalising?
(5 marks)
00
8.a.
Why hardening and tempering heat treatment is not practiced to a non-ferrous metals like aluminium?
(3 marks)
00
8.b.
Explain how duralumin is strengthened.
(4 marks)
00
8.c.
Explain how melleable iron is produced by heat treatment.
(3 marks)
00
OR
9.
Write explanatory note on:
(3 marks)
00
a) Titanium and its alloys.
b) Al-Cu phase diagram.
c) Gray cast iron and modular cast iron.
10.
Enumerate the characteristics, properties and applications of cements, glasses.
(10 marks)
00
OR
11.
Enumerate the characteristics, properties and applications of composite and polymers.
(10 marks)
00
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