Tuesday, 4 June 2013

Second Day

What did you do today?
- Composite material processing
- Tensile testing of engineering materials
- Scanning electron microscope

Briefly describe your day's activities

Composite material processing

We made carbon fiber and glass fiber using epoxy and hardener.  We also used plastic sheets, (huge) tissue papers and teflon sheets. The professor let us have a glimpse of what we are about to make, or a part of it anyways.
He told us that without the hardener, the fiber would be just like a fabric cloth: soft and smooth but stronger. Then he showed us a carbon fiber and a glass fiber WITH the hardener, and it is much harder. He even whacked it against the table to prove it.

This topic interests me as we can make numerous things with composite material processing. We can just take multiple objects and take some of their properties from each one of them and combine them together in order to create something more useful and effective.

Tensile testing of engineering materials

In the tensile testing of engineering materials, I learnt about the different mechanical properties of materials, tensile strain and tensile stress, Young Modulus and the typical tensile curve (graph).

This topic is generally about testing the toughness/ stiffness, ductility, and young modulus of a material.

The materials we tested:
-mild steel
-aluminium-copper alloy
-polyethylene (plastic)
-PMMA* bar

*PMMA= Poly methyl methacrylate

*Special thing i learnt* --> Polymer is another word/ meaning for plastic

Scanning Electron Microscope

Electron microscopes are capable of seeing things which are really small but some of them do not have enough power to see an atom.

Parts of a typical modern EM
~electron gun -----------> shoots an electron beam to the specimen. The beam is later deflected into the scope.

~electron column----------> focus and creates the image of the specimen with the electron beam projected by the electron gun.

~specimen chamber ---------> sustained at high vacuum so that it minimizes the scattering of the electron beam reaching the specimen.

What did u learn today?
-I learnt that there are many different types of composites used such as dispersion strengthened composites, particle-reinforced composites, and fiber-reinforced composites.
-I learnt that the electron microscope is useful for the discovery of new life. However, 10 000 volts of electricity can be dangerous if not used correctly...

How do you feel about today's activities?
- I am interested in the composite material processing as it has endless ideas and combinations of properties for new and more effective inventions.
- The electron microscope requires a lot of caution when in use because not only that it might kill you, when you damage it, you have to pay a lot of money.

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