Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 4th Sem New 2142106 Plastic Deformation Of Metals Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? IV (New) EXAMINATION ? WINTER 2019
Subject Code: 2142106 Date: 07/12/2019
Subject Name: Plastic Deformation of Metals
Time: 10:30 AM TO 01:00 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 a labeled stress strain diagram for ductile and brittle material. Explain
yield point phenomena with neat sketch.
03
(b)
Differentiate Slip and Twinning as mechanism of Plastic deformation.
04
(c)
Define the Terms: (i) Young?s Modulus (ii) Shear Modulus (iii) True Stress
& True strain (iv) Engineering Stress and Engineering Strain v) Ultimate
tensile stress vi) Proof stress vii) braking strength.
07
Q.2 (a)
Discuss the various techniques of observation of dislocation.
03
(b)
Differentiate between plastic deformation by slip and twinning.
04
(c)
Discuss the mechanism of Frank-Read source of dislocation multiplications.
07
OR
(c)
What is Schimid?s law? Derive the expression of critical resolved shear stress
07
Q.3 (a)
Write a formula stating relationship between Shear Modulus (G), Elastic
Modulus(E), and Possion?s ratio of materials
03
(b)
What is Hall petch relationship? Discuss the basis of strengthening of
materials by grain ?size reduction method.
04
(c)
Define Dislocation? Differentiate Edge and Screw dislocation with neat
sketch.
07
OR
Q.3 (a)
What is Slip system? What is the use of Burger Circuit?
03
(b)
Differentiate between the annealing twins and the deformation twins with
neat schematics.
04
(c)
Differentiate the following with help of schematic representation
(i) Ductile fracture and Brittle fracture
(ii) Intergranular fracture and Trans granular fracture
07
Q.4 (a)
Enlist various strengthening mechanisms in metallic alloys.
03
(b)
Differentiate the climb and the cross slip of dislocation with the help of
schematics.
04
(c)
A Large plate is fabricated from a steel alloy that has a plain strain fracture
toughness of 45 MPa ? ?? . If during service use, the plate is exposed to a
tensile stress of 250 MPa, determine the minimum length of a surface crack
that will lead to fracture (Assume f=1.0)
07
OR
Q.4 (a)
Explain ?Ductile-Brittle Transition Temperature? (DBTT) curve
03
(b)
With a Neat Sketch, explain how dislocation line can end abruptly inside a
crystal itself by forming a continuous loop?
04
(c)
Derive a Griffith?s equation for a propagation of cracks in brittle material and
using equation calculate, of The half-length of cracks in a steel is 3?m. Taking
E= 150GNm-2 , Estimate the brittle fracture strength at low temperature, if
the surface energy is 1.5 Jm-2
07
FirstRanker.com - FirstRanker's Choice
1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? IV (New) EXAMINATION ? WINTER 2019
Subject Code: 2142106 Date: 07/12/2019
Subject Name: Plastic Deformation of Metals
Time: 10:30 AM TO 01:00 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 a labeled stress strain diagram for ductile and brittle material. Explain
yield point phenomena with neat sketch.
03
(b)
Differentiate Slip and Twinning as mechanism of Plastic deformation.
04
(c)
Define the Terms: (i) Young?s Modulus (ii) Shear Modulus (iii) True Stress
& True strain (iv) Engineering Stress and Engineering Strain v) Ultimate
tensile stress vi) Proof stress vii) braking strength.
07
Q.2 (a)
Discuss the various techniques of observation of dislocation.
03
(b)
Differentiate between plastic deformation by slip and twinning.
04
(c)
Discuss the mechanism of Frank-Read source of dislocation multiplications.
07
OR
(c)
What is Schimid?s law? Derive the expression of critical resolved shear stress
07
Q.3 (a)
Write a formula stating relationship between Shear Modulus (G), Elastic
Modulus(E), and Possion?s ratio of materials
03
(b)
What is Hall petch relationship? Discuss the basis of strengthening of
materials by grain ?size reduction method.
04
(c)
Define Dislocation? Differentiate Edge and Screw dislocation with neat
sketch.
07
OR
Q.3 (a)
What is Slip system? What is the use of Burger Circuit?
03
(b)
Differentiate between the annealing twins and the deformation twins with
neat schematics.
04
(c)
Differentiate the following with help of schematic representation
(i) Ductile fracture and Brittle fracture
(ii) Intergranular fracture and Trans granular fracture
07
Q.4 (a)
Enlist various strengthening mechanisms in metallic alloys.
03
(b)
Differentiate the climb and the cross slip of dislocation with the help of
schematics.
04
(c)
A Large plate is fabricated from a steel alloy that has a plain strain fracture
toughness of 45 MPa ? ?? . If during service use, the plate is exposed to a
tensile stress of 250 MPa, determine the minimum length of a surface crack
that will lead to fracture (Assume f=1.0)
07
OR
Q.4 (a)
Explain ?Ductile-Brittle Transition Temperature? (DBTT) curve
03
(b)
With a Neat Sketch, explain how dislocation line can end abruptly inside a
crystal itself by forming a continuous loop?
04
(c)
Derive a Griffith?s equation for a propagation of cracks in brittle material and
using equation calculate, of The half-length of cracks in a steel is 3?m. Taking
E= 150GNm-2 , Estimate the brittle fracture strength at low temperature, if
the surface energy is 1.5 Jm-2
07
2
Q.5 (a)
Draw schematic of grain boundary strengthening effect.
03
(b)
What are the pre-requisite for an alloy to be age-hardenable? Explain
giving suitable example.
04
(c)
Compare recovery and recrystallisation in terms of (i) driving force (ii)
mechanisms, and (iii) effects on mechanical properties
07
OR
Q.5 (a)
Define Strain Hardening effect. State the effect of it on the mechanical
properties of steels?
03
(b)
What is creep? Draw a typical creep curve and discuss its different regions.
04
(c)
Draw typical S-N Curve for an aluminium alloy and steel . Define
the terms: (i) Endurance Limit (ii) Fatigue strength and (iii)
Fatigue life.
07
*************
FirstRanker.com - FirstRanker's Choice
This post was last modified on 20 February 2020