Choose either a plastic, composite, titanium alloy or aluminium alloy for the applications below and briefly explain your choice. In explaining your choice, relate the properties the application requires to the mechanical properties of your selected material. In terms of how to specify the material type, for:
a. Aluminium: specify the series, eg. 2xxx
b. Steel: steel type, eg "stainless"
c. Titanium: a or b or a-b alloy
d. Polymers: Thermoplastic/Thermoset/Elastomer
e. Composite: Nanocomposite/Fibre Reinforced composite (specify the fibre out of kevlar/carbon/glass)
- Bumper bar of a family car
- Floor of the passenger cabin of a commercial airliner
- Pressure vessel containing caustic (sodium hydroxide) and bauxite used to refine aluminium
- Equipment used to shape yellow hot steel during forging
- A fuel tank for an hydrogen engine car
1. Given the information in the Info Pack, make a guess as to why overaged aluminium alloys are not as tough as underaged ones.
2. State the differences between 7075-T651 and 7475-T651 in terms of composition, yield strength and fracture toughness
3. State the effect of oxygen content on the toughness of Titanium.
4. View the video below and list at least two different ways exposure to oxygen is controlled during manufacturing:
5. What is the main advantage of Al-Li alloys compared to other aluminium alloys?
Individual Research Activity (between 500 and 600 words) (Choose ONE):
- Explain what are shape memory alloys are how they are used in engineering applications
- Explain how iron ore is refined to make steels
- Discover what is meant by "superplasticity" and explain how it can be used to advantage
- Describe what Nanocomposites are and choose one example to show how they are manufactured and where they are used in engineering situations.
Comments on marking:
The Materials Selection Activities and the Extension Questions will be given a total weighting of 0.3 and the Individual Research Activity will be given a weighting of 0.7. If you do not cite any references you will be given a failing grade for the research activity. See the marking critque for more detail on the research activity.
For each of the research topics, ensure as a minimum that the following is covered:
Shape Memory Alloys:
- Give some alloy classes and their detailed compositions as examples of shape memory alloys
- Explain what is meant by "shape memory" in terms of temperature, deformation and crystral structure
- Demonstrate the relevance of this phenonmenon to engineering applications and give some specific examples. Explain why shape memory alloys are used in these situations.
- Describe the process of making pig iron from iron ore, considering the ore size, equipment, raw materials and chemical reactions which need to occur to make the pig iron
- Describe the process of refining pig iron to make steel and make some simple comments regarding the different techniques which can be used (eg open hearth, electric arc, bessemer processes)
- Explain what is meant by the term "nanocomposite"
- Describe the atomic and microscopic structure of these materials
- Briefly describe how these are manufactured
- Provide some engineering examples of where nanocomposite materials are used and why they are used for that application. The more the specific the example, the better