PH8251 important questions Materials Science
PH8251 important questions Materials Science for Regulation 2017 Anna University. The important questions for PH8251 Materials Science is provided in this page to download.
Sample for PH8251 important questions MATERIALS SCIENCE:
What are Nanomaterials?
Nanomaterials are the materials with atoms arranged in nano sized clusters which become the building block of the material. Any material with a size between and 100 nm[ 10–9 m to 10–7m] is called nanomaterials.
Give the principle of Shape memory Alloys
The shape memory effect occurs between two temperatures states, ie., Martensite and Austenite. The SMA in the Marteniste is attained the temporary deformed shape when cooling. But when heating the martensite state is changed into Austenite state. During deformation the resistivity, thermal conductivity, Young modulus and yield strength are decreased by more than 40%.
Define Hysteresis of a SMA?
Hysteresis of a SMA is defined as the difference between the temperatures at which the material is 50% transformed to austenite when heating and 50% transformed to martensite when cooling.
Define Cooper pair.
The electron pairs called cooper pairs are formed at low temperature by overcoming the repulsive forces. The cooper pairs moves without scattering (without any resistance) in the lattice structure. Now the material becomes super conductor. This is also called as electron-phonon- electron interaction these two electrons have equal and opposite momentum and spins.
What are the characteristics of high temperature [high TC] superconductors?
High Superconductors have high temperatures.
They have a modified perovskite crystal structure.
Superconducting state is direction dependent.
These are oxides of copper with other elements.
These are reactive, brittle, and cannot be easily modified or joined.
For high superconductors, liquid Nitrogen is used instead of liquid helium.
| Subject Name | MATERIALS SCIENCE |
| Subject Code | PH8251 |
| Regulation | 2017 |
| File | important questions PDF |
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