Q1) Answer any FOUR:

• (a) Difference between steels and cast irons

• (b) Allotropic modifications of iron 309

• (c) Classifications of materials

• (d) Modes of deformation in materials
• (e) Stainless steels and its classification 324

2(a) Define critical cooling rate. Describe various cooling curves on TTT diagram for eutectoid steel and discuss the transformations.

2(b) Explain the property and micro-structure changes occurring during cold working and recrystallization annealing of metals.

3(a) Draw $F_e-(F_e)3C$ equilibrium diagram and label all the important temperatures, composition and phases clearly. Also write the invariant reactions.

3(b) Describe the cooling of 0.5%C steel to room temperature. Also find out the proportion of micro constituents in it at room temperature.

4(a) What is fatigue of metals? Explain the method of testing the metals for fatigue. Discuss the various methods used to increase fatigue life of a component.

4(b) What is Hardenability? What are factors affecting hardenability? Explain Jominy End Quench test.

5(a) How is surface hardening different from case hardening? Discuss any one of the case hardening methods in detail.

5(b) A continuous and aligned fibre-reinforced composite is to be produced consisting of 30 vol% aramid fibres in polycarbonate matrix. Find the modulus of the compositein longitudinal direction. (Given: modulus of elasticity for aramid fibre = 131 GPa and modulus of elasticity for polycarbonate = 2.4 GPa

5(c) What are smart materials? Discuss a few applications for smart materials.

Q6) Write short notes on (any four):

• (a) Nano materials and their sythesis route 331

• (b) Creep behaviour in metails 289 294

• (c) Dislocations and strain hardening 287

• (d) Isomorphous phase diagram 301

• (e) Retained austenite

• (f) MR fluids