Chapter 2 L06 Flashcards
What are ferrous and non ferreous metal?
- Ferreous: Metal that has iron as principal material
- Non-ferreous : Metal that don’t contain significant amounts of iron
Name the 5 most important non-ferrous metals
Aluminium, Copper, Magnesium, Titanium, Nickel
Name the most important properties of Aluminium
- Abundant material
- Good strenght / density ratio
- High corrosion resistance
Example: Comercial planes
Name most important properties of Copper
- Excellent electric conductivity
- High corrosion resistance
- Good weldeability and solderability (soldeable)
Example: Electric applications
Name most important properties of Magnesium
- Lowest density of all materials
- Good damping capacity (amortiguar)
- Low corrosion resistance
Example: Gear boxes
Name most important properties of Titanium
- Same as Aluminium but better
- More expensive than Aluminium
- High working temperatures
Example: Military planes
Depending on the lattice, what type of Titanium can we obtain?
T < 882° : α-Titanium : HCP
T > 882° : β-Titanium : BCC
What is the main advantage of α-titanium over β-titanium?
Better mechanical properties at extreme temperatures
Name most important properties of Nickel
- High density
- High material cost
- High working temperatures
Exmples: Turbines
What are Nickel based superalloys? Where are they typically used?
Nickel alloys with extraordianry high temperature stability. Used in turbine engines
How are ceramics classified?
- Consumer ceramics
- Functional ceramics
- Structural ceramics
How are ceramics formed?
“Notes”
Define sintering
Form solid ceramic appyling heat
What should be considered during the design process of ceramics?
2 parts:
- Forming process: Final geometry and quantity of pieces
- Sintering proccess: Temperature dependent
What characteristic of ceramic materials is of special interest for aerospace applications?
- High hardness
- High thermal resistance
- Low thermal expansion
Describe a thermal barrier coating.
A TBC is a layer design to protect thermally other components. In between the component and the TBC there are more intermediate layers
Describe the crystal structure of ionic ceramics.
In an ionic cermaic, the crystal is formed from anions (-) and cations (+), which are attracted to each other due to their oppostie sign.
What is the difference between green machining and hard machining
During the production process, green machining (before heat treatment) is applied before hard machining (after heat treatment)
Why is the mean value of strength of ceramics insufficent for characteriaztion?
Reasons: Pores and micro-cracks
