Note 1 and 2 Flashcards
(27 cards)
Define a composite material?
A material deliberately made from a combination of more than one constituent, where the combination gives advantages in properties.
When discussing 2-PHASE MATERIAL, what does it consider?
Metals
Ceramics
Polymers
When discussing PARTICLE REINFORCED, what does it consider?
Size
Shape
Arrangement
Material
When discussing FIBRE REINFORCED, what does it consider?
Short
Continuous
Orientation
Arrangement
Materials
When discussing COMPOSITE STRUCTURE, what does it consider?
Laminated
Materials
Sandwich
Panel
What advantages can a composite structure have?
- Increased stiffness.
- Increased strength.
- Reduced density.
- Increased toughness.
- Increased temperature resistance.
- Improved processibility (sometimes).
- Lower cost (sometimes)
- Modified electrical conductivity.
- Modified thermal, optical, magnetic behaviour.
- Improved corrosion resistance.
- Lower gas permeability.
- Modified dynamic behaviour.
What are considered as the matrix materials?
Metals
Ceramic
Thermosetting polymers
Thermoplastic polymers
What are the main role of matrix materials?
- Transfer stress between reinforcing fibres / particles.
- Provide toughness.
- Improve processibility.
What are the properties of general METALS?
Mainly aluminium, magnesium, titanium alloys.
- Density: 3,000 - 5,000 (kg/m^3)
- Moderate temperature resistance (up to 800 C for Ti alloys)
- Good toughness, good strength, moderate processibility.
What are the properties of general CERAMICS?
Alumina, Zirconia, Silicon Carbide, Silicon Nitride, Ceramic glasses.
- Density: 2,000- 3,000 (kg/m^3).
- Very good temperature resistance (to 1,300 C).
- Poor toughness, poor processibility.
What are the properties of general THERMOSETTING POLYMERS?
Epoxies, polyesters, phenolics.
- Density: 1,000 to 1,300 (kg/m^3).
- Poor temperature resistance (up to 250 C).
- Moderate toughness, lower strength, excellent processibility.
What are the properties of general THERMOPLACTIC POLYMERS?
Polypropylene, nylon, PEEK (& bio-polymers.
- Density: 980 -1,300 (kg/m^3).
- Poor temperature resistance (up to 250 C).
- Excellent toughness, lowest strength, good processibility.
What are the main role of PARTICULATE REINFORCEMENTS?
- Increased stiffness.
- Increased hardness.
- Reduce cost.
- Modified other properties such as density, conductivity, thermal, optical, magnetic properties.
What can materials can be included as PARTICULATE REINFORCEMENTS?
- Ceramics: calcium, carbonate, silica, calcium hydroxide, titanium dioxide, mica, kaolins, wollastonite, other clays (including nano-particles).
- Glass particles and spheres.
- Carbon.
- Metals.
- Wood flour.
What are the main roles of FIBRE REINFORCEMENTS?
- Increased stiffness,
- Increased strength.
- Increased toughness.
What are the properties of GLASS as a fibre reinforcement?
Low cost, good stiffness, reasonable strength, low toughness, good temp resistance.
What are the properties of CARBON as a fibre reinforcement?
More expensive, good stiffness and strength, moderate toughness, moderate temp resistance.
What are the properties of POLYRAMIDS (KELVAR) as a fibre reinforcement?
Quite expensive, moderate stiffness and strength, excellent toughness, moderate temperature resistance.
What are the properties of OTHER POLYMERS (POLYETHYLENE, POLYPROPYLENE) as a fibre reinforcement?
Range of cost, moderate to low strength and stiffness, excellent toughness, low temperature resistance, poor adhesion.
What are the properties of CERAMICS WHISKERS as a fibre reinforcement?
(these include silicon carbide, boron, silicon nitride, aluminium oxide).
High stiffness, high temperature resistance, low toughness, only short fibre.
What are the properties of CARBON NANOTUBE as a fibre reinforcement?
Very small fibres, very high strength and stiffness, good toughness, very expensive.
What are the properties of NATURL FIBRE (MAINLY PLANT-BASED - A FEW ANIMALS) as a fibre reinforcement?
Range of properties, cost can be very low to quite high, variability in properties, high level of water absorption, generally lower environmental impact.
Fibres from main stem (mainly cellulose), leaf and husk (some mineral fibres).
Wood, cotton, hemp, jute, sisal, pineapple, banana, rice, etc.
What is an interface?
The surface between reinforcement and matrix.
What is an interphase?
Region of matrix close to reinforcement, which can be different due to: Different level of cure, different crystallinity and microstructure, stresses.
