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APJ ABDULKALAM TECHNOLOGICAL UNIVERSITY
Third semester M. Tech Degree Examination December-2017

Branch: Mechanical Engineering
Stream : Machine Design

01 ME7123 Mechanical Behaviour of Materials

Answer any two questionsfrom each module.
Limit answers to the required points

Max Marks: 60 Duration : 3 hours
PART. A

1. (8) Calculate the Atomic packing factor, maximum linear and maximum planar density of (4) a
BCC crystal.
(b) Explain the defects in solids and its effects. (5)

2. (a) Find the yield stress of single crystal of a metal that has the FCC crystal structure is oriented
such that a tensile stress is applied parallel to the direction (1 10], If the critical
(5) resolved shear stress for this material is 1 .75 MPa,

(b) Derive the expressions for true stress and true strain. Plot these on stress- strain curve. (4)

3 (a) What are the effects of strain rate and temperature on the tensile property of the (4) material?

Explain.
(b) Briefly explain the various mechanical testing methods. (5)
PART B
4, (a) Explain the strengthening of an alloy by grain size reduction. (4)

(b) Write notes on recovery, recrystallization and grain growth. Plot the variation of (5) tensile
strength and ductility during these three stages.

5.(a) With the help of iron carbon phase diagram, state and explain eutectoid reaction. (5) Show the
micro structural changes while cooling liquid steel through eutectoid point.
(b) What is martensite? Explain martensite transformation with the help of TIT diagram. (4)

6(a) ۱۷۷۲۲٢ notes on applications of different types of composite materials. (4)

(b) Draw the atomic bonding structure of graphite. Discuss its properties and engineering (5)
applications.