Mechanical Engineering (Semester 3)
TOTAL MARKS: 100
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.
1 (a) With neat sketch,explain body centered cubic face centered and closed packed hexagonal srtructures with exampe.(9 marks)
1 (b) Derive expresion for atomic packing factor of BCC,FCC and HCP structure(7 marks)
1 (c) Briefly explain the different types of point defects (4 marks)
2 (a) With the help of stress -strain digram.expalin the behaviour of ductile and brittle materials (8 marks)
2 (b) The follwing data have been obatined in hardness test of speciments.calculate the hardness number.assume dia of ball indentor =10mm.
| Material | types | Load (kgf) | impression(mgf) |
| A | brinells | 500 | 4.6 |
| B | vickers | 5 | 0.28 |
(6 marks)
2 (c) Define the following terms Thoughness,Resiliance ,Proof stress and ductility.(6 marks)
3 (a) With neat digram , explain the frature in the following:
Ductile
Brittle
Fatigue(12 marks)
3 (b) Explain the three stages of creep with a neat sketch and its characteristic (8 marks)
4 (a) with net diagram ,explain the process of nuclation (4 marks)
4 (b) Write a note on Gibbs phase rule with an example (4 marks)
4 (c) with the help of cooling curve,explain how solidification process begins in pure metals (6 marks)
4 (d) Briefly explain the rules behind the solid solubility(5 marks)
5 (a) Construct the Ag-Cu phase diagram using following data;
Melting point of Ag=960.5°c
Melting point of Cu=1085°C
Eutectic point=779.4°c
Eutectic compoistion =28.1%Cu
Maximum solubilty of Ag in Cu and Cu in Ag is 8%
maximum solubilty of Cu in Ag in Cu is 2%.Assume the liquids ,solidus and solves lines are stright .calculate:
Amount of eutectic in 20% Cu,80%Ag alloy at 700°c and
Percentage and composition of solid phase in 60%Cu and 40% Ag alloy 400°C.(10 marks)
5 (b) What is level rule?Explain how it is useful.(5 marks)
5 (c) What is phase diagrams?how are they classified?(5 marks)
6 (a) Draw Iron -carbon equlibrium diagram and explain primary crystallization of steel hypoeutectic cast iron hypereutectic cast iron(10 marks)
6 (b) Define the following anneling ,normalization,tempring ,carburizing and nitriding(10 marks)
7 (a) How cast iron classified ?What are the properties of cast iron?(8 marks)
7 (b) How generally steels are classified ?consider at least two compostion mixture .mention its application and advantages(6 marks)
7 (c) Explain the composition ,properties and used of at least two copper based alloys(6 marks)
8 (a) Derive an expresion for load distribution in a composite for longitudianal loading of fiber reinforced composite(10 marks)
8 (b) With a neat diagram ,explain the hand laminating process(10 marks)
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