Material Science: Frequently Asked Questions in AMIE Exams

1. MATERIAL SCIENCE
MOST FREQUENTLY ASKED QUESTIONS IN AMIE EXAMS

2. CERAMIC MATERIALS
• Differentiate between ceramics and glass, with examples. What is glass
transition temperature? What type of glass is used in spectacle lenses?
• Why are ceramics brittle in general?
• Define thermal stresses. What measures may be taken to reduce the
likelihood of thermal shock of a ceramic piece?
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3. CRYSTAL STRUCTURE
• Calculate and compare the atomic packing factors of the FCC and BCC unit
cells.
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4. DEFECTS IN SOLIDS
• Differentiate between Frenkel and Schottky defects.
• Discuss major differences between edge and screw dislocation.
• What is a Burger vector? Show it by drawing a Burger circuit.
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5. DIFFUSION IN SOLIDS
• State Fick’s second law of diffusion. Describe how it affects heat treatment
in carburization of low carbon steels.
• What is meant by the term “diffusivity”? What is steady state diffusion?
How does it depend on temperature. Derive Fick’s law of diffusion.
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6. DEFORMATION OF METALS
• What is the difference between the slip and twinning mechanisms of plastic
deformation of metals?
• Explain briefly plastic deformation by slip and twinning.
• What is critical resolved shear stress? Derive an expression for the same.
• Briefly cite the differences between recovery and recrystallization processes.
• Compare - cold working and hot working.
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7. ELECTRONIC PROPERTIES OF
MATERIALS
• What is diamagnetism and paramagnetism? Explain in brief. Name one
material of each type.
• Differentiate between soft and hard magnets. Give two examples of soft
magnetic materials.
• Draw the hysteresis loop for hard and soft magnets, and explain the
differences in behaviour in response to alternating field
with emphasis on the magnetization parameters.
• Discuss zone theory of solids and explain zones in conductors and insulators.
• What are semiconductors? Explain semiconductors, intrinsic and extrinsic
semiconductors.
• With the help of energy band diagrams distinguish between insulators,
conductors and semiconductor material.
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8. HEAT TREATMENT OF STEELS
• Differentiate between annealing and normalizing. Discuss the purposes for
which these treatments are done.
• Discuss the tempering process. What are main aims of tempering? Suggest
whether tempering should be done at higher or lower temperature with
reasons.
• Define hardness and hardenability, explaining their difference. Mention the
factors which affect hardenability.
• What is age hardening? What are the basic requirements for an alloy to
behave as age hardenable. Mention the steps in the process of age
hardening.
• Mention four strengthening mechanisms of metals and alloys, and explain
any one of them
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9. ENGINEERING MATERIALS
• What are nano materials? Give two unique properties of Nanomaterials
explaining the cause. Discuss their engineering applications.
• What is composite materials? What are advantages of composite materials
over other engineering alloys? Enumerate the difference particle and fibre
reinforced composite.
•
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10. MECHANICAL & THERMAL
PROPERTIES
• What is creep? Draw a typical creep curve and label its important areas.
• Draw a typical creep curve of strain vs. time at constant stress and constant
elevated temperature, clearly showing the instantaneous deformation, three
stages of creep and rupture. At what temperature does creep become significant?
• Derive the relationship between Engineering Strain and True Strain,
Engineering Stress and True Stress.
• What is true stress? How true stress is related to engineering stress?
• What is ductile fracture? Compare ductile and brittle fracture.
• State the Griffith theory of fracture? What modification is required for
application to aluminium?
• Define thermal stress. Discuss stresses due to restrained thermal expansion and
contraction.
• What are refractories? Discuss their industrial applications.
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11. PHASE TRANSFORMATION
• What is Gibb's phase rule? Explain its application with reference to binary
phase diagram.
• Draw the iron - iron carbide phase system. Clearly indicating the phase
present at different temperatures and carbon content.
• Draw a typical TTT diagram and explain the term critical cooling rate with
reference to the diagram.
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12. POLYMERS
• What do you understand by polymerization? What is the difference between
addition polymerization and condensation polymerization?
• Discuss briefly the different polymerization mechanisms.
• Distinguish between thermoplastics and thermosetting plastics.
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13. ANSWERS
• For detailed answers, please refer study materials from AMIE(I) Study
Circle.
• Download prospectus from
http://www.amiestudycircle.com/prospectus/Prospectus.pdf
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