•To observe how the three types of materials behave in their mechanical properties under the tensile and bend test
•To understand the major factors that determines those mechanical properties.
1. Vent the chamber. This is to enable the specimen to be inserted into the chamber.
2. Press evac. This is to remove the air from the chamber as to make it a vacuum, so that the electrons can travel down to the specimen freely without getting disrupted by the air.
3. Set the optimal acceleration voltage, working distance and spot size.
-Acceleration voltage : The voltage which the electrons will be beamed down to the specimen. Too high a voltage will result in the specimen melting and damaging the SEM.
-Working distance : The distance between the specimen and the electron gun. This is usually in millimeters.
- Spot size : The size and width of the electron beam. It is usually in direct proportion to the specimen size.
4. Turn up the filament SLOWLY. A sudden rush in turning up the filament will result in the filament melting. Turning it up too much will also have a similar effect.
5. Start to beam the electron to the specimen. After this you should get a blurry, unfined image.
6. Adjust the focus knobs, brightness, contrast, X and Y magnifications and general magnification until the image is clear and satisfying.
7. Save the image.
8. Set the voltage to 0 and turn off the beam.