What is graphene? Describe the bonding in graphene. Explain the band structure of graphene on E-k diagram.
See Answer →What are shape memory materials? Explain the phase transition hysteresis observed in NiTi alloy giving rise to shape memory phenomenon. Discuss any two applications of shape memory materials.
See Answer →Explain the phenomena of Colossal Magnetoresistance (CMR) and Giant Magnetoresistance (GMR). Give examples of materials where these effects are observed.
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Define corrosion in case of materials. Discuss the five major factors affecting /promoting corrosion process.
See Answer →What is meant by "thermal shock" experienced by the materials? How can it be reduced? State the expression for thermal shock resistance (TRS) explaining all the terms involved.
See Answer →Draw a typical stress-strain curve of a material. Define various mechanical strengths and indicate corresponding deformation regions on this plot.
See Answer →Explain the Avrami and Johnson-Mehl models of computing phase transformation rates based on their assumptions and growth mechanisms.
See Answer →What are eutectic phase diagrams? With the help of a schematic diagram for a binary system explain the significance of eutectic point and liquidus, solidus & solvus curves.
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Based on the diffusion mechanisms involved explain why carbon atom diffusion is faster than nickel atom diffusion in iron lattice.
See Answer →What is dislocation defect? Discuss its role in the crystal growth.
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Calculate the equilibrium concentration of vacancies in a copper crystal at 1000 K. Given that melting point of copper is 1083°C and enthalpy of vacancy formation in copper is 120 kJ per mole.
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Calculate the equilibrium concentration of vacancies in a copper crystal at 1000 K. Given that melting point of copper is 1083°C and enthalpy of vacancy formation in copper is 120 kJ per mole.
See Answer →Explain with appropriate diagrams various point defects observed in solid crystals.
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What is epitaxial growth? What are the advantages of MBE growth technique? State its applications.
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Describe the importance and cost advantages of powder metallurgy in materials processing.
See Answer →Calculate the mass of phosphorus required to make a silicon crystal with 107 cm doping density, if the initial melt load of silicon is 50 kg. The density of silicon in the melt is 2.5 g cm³ and phosphorus has an atomic weight of 30.97u. Assume that the segregation coefficient ko=0.35 is constant throughout the growth process.
See Answer →Explain with diagram the float zone method of crystal growth. State its advantages over the Czochralski method.
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What are solid solutions? Explain the rules (Hume-Rothery) governing the formation of substitutional solid solutions.
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What are glassy alloys? Discuss their mechanical properties vis-à-vis normal metal alloys and ceramic oxide materials. State any four technological applications of glassy alloys.
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Explain with diagram, how many identical points are created by a 3 roto-inversion operation. Among 3-fold rotation and 3 roto-inversion operation, which one has higher order? Why?
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