Heat Treatment

Assignment 1

DBT 302 Heat Treatment

*submit 15th Sept 2014

1. Give examples of materials based on inorganic glasses that are made by solidification.

1. What do the terms “primary” and “Secondary processing” mean?

1. Why are ceramic materials not prepared by melting and casting?

1. Define the following terms;

1. Nucleation embryo
2. Heterogeneous nucleation
3. Homogeneous nucleation

1. Does water freeze at 0°C and boil at 100°C? Explain.

1. Does ice melt at 0°C? Explain.

7-        Figure below shows the development of microstructure in eutectic alloys for Pb-Sn system. By referring to 2–19wt%Sn alloys composition, describe the formation process which occurred from point A, B until point C.

[pic 1][pic 2][pic 3][pic 4]

Microstructure development in eutectic alloys for Pb-Sn system.

1. Define the following terms:

1. Component

1. Phase

1. Solubility limit

9-        Figure below shows the phase diagram of Pb-Sn system 

i)        Draw the microstructure of hypoeutectic alloy if cooled from

 (L → α + β) at point (a), (b), (c) and (d).

[pic 5]

1. List down FOUR (4) classes of alloys in the Pb-Sn phase diagram system.

1. Describe about α phase and β phase in term of amount and composition at temperature 183°C along the eutectic isotherm.  

10-                In Figure below, at the point of 10wt%Pb at temperature 195oC:

1. Identify the phases appear.
2. Define the hypoeutectic and hypereutectic alloys.
3. Calculate the composition of phases Cβ and CL.
4. Calculate the amount of phases Wβ and WL.

[pic 6]

11-        Figure below shows the phase diagram of Pb-Sn system 

i)        Draw the microstructure at A, B and C

[pic 7]