Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 4th Sem New 2142106 Plastic Deformation Of Metals Previous Question Paper
1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?IV (NEW) EXAMINATION ? WINTER 2018
Subject Code: 2142106 Date: 22/11/2018
Subject Name: Plastic Deformation of Metals
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
MARKS
Q.1 (a) Draw sample stress-strain diagrams for ductile and brittle
material.
03
(b) Explain yield point phenomena with a neat sketch. 04
(c) With the help of neat sketches, differentiate between edge and
screw dislocations.
07
Q.2 (a) Multiple Choice Questions:
1) Which of the following is false?
a. Line defects are thermodynamically stable
b. Dislocation can end inside a crystal without
forming loop
c. ABC ABC ABC? is stacking sequence for HCP
crystal
d. All of the above
2) Figure-out the odd point in the following
a. Proportional limit
b. Fracture point
c. Elastic limit
d. Yield point
3) Requirement for cross-slip movement of dislocation
a. Preferred slip plane
b. Preferred slip direction
c. No preferred slip plane
d. No preferred slip direction
03
(b) Draw & give difference between engineering stress strain curve &
true stress strain curve.
04
(c) What is slip system? Explain why FCC metal is usually more
ductile than BCC & HCP Metals.
07
OR
(c) Differentiate between slip and twinning as mechanisms of plastic
deformations.
07
Q.3 (a) Explain with neat schematic ?critical resolved shear stress for slip. 03
(b) Define effective stress. Write down equations for calculating
effective stress under Tresca criterion & Von Mises Criteria.
04
(c) What is strain hardening effect? What is the effect of it on the
mechanical properties of metals?
07
OR
Q.3 (a) Define dislocation. What are sources of dislocations? 03
(b) What is ductile brittle transition temperature (DBTT)? 04
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?IV (NEW) EXAMINATION ? WINTER 2018
Subject Code: 2142106 Date: 22/11/2018
Subject Name: Plastic Deformation of Metals
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
MARKS
Q.1 (a) Draw sample stress-strain diagrams for ductile and brittle
material.
03
(b) Explain yield point phenomena with a neat sketch. 04
(c) With the help of neat sketches, differentiate between edge and
screw dislocations.
07
Q.2 (a) Multiple Choice Questions:
1) Which of the following is false?
a. Line defects are thermodynamically stable
b. Dislocation can end inside a crystal without
forming loop
c. ABC ABC ABC? is stacking sequence for HCP
crystal
d. All of the above
2) Figure-out the odd point in the following
a. Proportional limit
b. Fracture point
c. Elastic limit
d. Yield point
3) Requirement for cross-slip movement of dislocation
a. Preferred slip plane
b. Preferred slip direction
c. No preferred slip plane
d. No preferred slip direction
03
(b) Draw & give difference between engineering stress strain curve &
true stress strain curve.
04
(c) What is slip system? Explain why FCC metal is usually more
ductile than BCC & HCP Metals.
07
OR
(c) Differentiate between slip and twinning as mechanisms of plastic
deformations.
07
Q.3 (a) Explain with neat schematic ?critical resolved shear stress for slip. 03
(b) Define effective stress. Write down equations for calculating
effective stress under Tresca criterion & Von Mises Criteria.
04
(c) What is strain hardening effect? What is the effect of it on the
mechanical properties of metals?
07
OR
Q.3 (a) Define dislocation. What are sources of dislocations? 03
(b) What is ductile brittle transition temperature (DBTT)? 04
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2
(c) Define solid solution. Explain Hume Rothery rules for formation
of substitutional solid solution.
07
Q.4 (a) What is the role of grain boundaries in dislocation motion? 03
(b) Explain fatigue test with the help of S-N Diagram. 04
(c) Write down procedure of ?Mohr?s Circle? analysis for solving
Principal Stresses.
07
OR
Q.4 (a) What are the prerequisites for an alloy to be age-hardenable? 03
(b) Draw fatigue curves for ferrous & non ferrous metals systems.
Define fatigue limit.
04
(c) Why is annealing required after cold working of Steels? Explain
the structural changes that the material goes through while
annealing with the help of sketches.
07
Q.5 (a) Distinguish between sessile dislocation and glissile dislocations. 03
(b) Explain about the multiplication of dislocations through Frank
Reed source.
04
(c) What is Equi-cohesive Temperature? Explain in respect of Creep
Fractures.
07
OR
Q.5 (a) Explain Kinks and Jogs with the help of neat diagrams. 03
(b) Write a detailed classification of crystal imperfections. 04
(c) Derive the Griffith equation for brittle fracture. 07
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This post was last modified on 20 February 2020