Visvesvaraya Technological University (VTU) 2005 B.E Mechanical Engineering Material science and metallurgy - Question Paper

Note:Answer 2 ques. from part A,two from partB and 1 ques. from part C
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PART A
1.a)define atomic packing factor.calculate APF for BCC system. (3M)
b)copper has an FCC structure and an atom radius of 0.1278nun.calculate its density.given at.wt. of cu=63.54.avogadro number=0.602*10^24 (5M)
c)draw a schematic stress strain curve for mild steel and discuss the determination of different mechanical properties from the curve. (12M)

2.a)define creep.draw a typical creep curve and indicate the stages of creep.which stage is of practical significance?justify your ans. (8M)
b)state and discuss fick's 1st legal regulations of diffusion. (6M)
c)calculate the diffusivity of copper in AL at 1000deg.given Do=1.5*10^-5m^2/s Q=126kjmol^-1 R=8.314jkmol. (6M)

3.a)how is fatigue strength of materials determined? (8M)
b)explain the mechanism of fatigue crack growth in ductile materials. (8M)
c)differentiate ranging from ductile and brittle fractures. (4M)

PART B
4.a)draw fe-fe3c phase diagram and identify the phase fields. (10M)
b)state gibbs phase rule and discuss every term. (6M)
c)calculate the amount of pro eutectoid ferrite,eutectoid ferrite and cementite in 0.4%carbon steel at room temperature. (4M)

5.a)explain the concept of critical radius for nucleation during solidification. (8M)
b)what is a solid solution?with suitable examples discuss the various kinds of solid solutions. (8M)
c)A binary alloy of M and N contains 56% solid phase and 44% of liquid phase are 28% N and 70%N respectively.what is the overall composition of the alloy? (4M)

6.a)explain annealing and normalizing. (4M)
b)what is tempering?why is it done? (3M)
c)what is the purpose of surface hardening treatment?what kind of steels can be surface hardened and how? (10M)
d)what is age-hardening ?what are its requirement? (3M)

PART C
7.a)what is composite material?what are its constituents and why are there present?how do you classify composites?what are the advantages and limitations? (12M)
b)write a note on AL-SI alloys. (8M)

8.a)distinguish ranging from alpha and alpha and beta brasses with respect to composition,properties and applications. (6M)
b)give the composition structure and uses of
s.G iron,malleable cast iron and grey cast iron (5M)
c)write a note on FRPs. (9M)

Earning:   Approval pending.