JNTU II B.Tech I Semester Regular Examinations, November 2008
METALLURGY AND MATERIAL SCIENCE
( Common to Mechanical Engineering, Mechatronics, Production
Engineering and Automobile Engineering)
1. (a) What is the importance of grain size in steel? How do you determine grain size of the given steel?
(b) Explain why grains are stronger than grain boundaries at high temperature
and grain boundaries are stronger than grains at room temperatures?
2. (a) Distinguish between commercially pure metal and an alloy?
(b) What is a master alloy? What are its chief characteristics?
(c) Justify the statement “ Alloy is a material which is expected of a metal, but
it is not a pure metallic element”.
3. (a) Name possible types of Cementite in Fe-Fe3C diagram? Explain why proeutectiod product forms at grain boundaries of austenite ?
(b) Differentiate between
i. Proeutectiod ferrite and eutectoid ferrite
ii. Hypoeutectic and Hyper eutectic white cast iron.
4. What are four basic types of cast Irons? Explain them with respect to properties, microstructure with a diagram and applications?
5. (a) What is an alloy? Give two examples.
(b) Discuss in detail the effect of alloying elements in steels.
6. (a) Alpha brasses are cold worked while Alpha-Beta brasses are hot worked. Explain.
(b) Extensive coring occurs in cast bronzes compared to cast brasses. Give reasons.
(c) What is dezincification? What are its effects? How is it prevented?
7. (a) In a heterogeneous multiphase refractory, what are the microstructural features present? Mention their applications.
(b) Why chemically synthesized magnesium-aluminate spinel is used exclusively as refractory in molten salt electrolysis cell for producing magnesium?
8. (a) What is aspect ratio? Why is it so important?
(b) Discuss briefly about whisker reinforced composites?