What are the common metals used as matrix materials? What are their advantages and disadvantages?

The common metals used as matrix materials are aluminum, titanium and copper.

Advantages:

1. Higher transfer strength,
2. High toughness (in contrast with brittle behavior of polymers and ceramics)
3. The absence of moisture and
4. High thermal conductivity (copper and aluminum).

Dis-advantages:

1. Heavier
2. More susceptible to interface degradation at the fiber/matrix interface and
3. Corrosion is a major problem for the metals

            The attractive feature of the metal matrix composites is the higher temperature use. The aluminum matrix composite can be used in the temperature range upward of 300ºC while the titanium matrix composites can be used above 800 .
           
What are the ceramic matrix materials? What are their advantages and disadvantages?

The carbon, silicon carbide and silicon nitride are ceramics and used as matrix materials.

Ceramic:
           
The advantages of the ceramic matrix materials are:

1. The ceramic composites have very high temperature range of above 2000  .
2. High elastic modulus
3. Low density

The disadvantages of the ceramic matrix materials are:

1. The ceramics are very brittle in nature. 
2. Hence, they are susceptible to flows.

Carbon

The advantages of the carbon matrix materials are:

1. High temperature at 2200 .
2. Carbon/carbon bond is stronger at elevated temperature than room temperature.

The disadvantages of the carbon matrix materials are:

1. The fabrication is expensive.
2. The multistage processing results in complexity and higher additional cost.

It should be noted that a composite with carbon fibres as reinforcement as well as matrix material is known as carbon-carbon composite. The application of carbon-carbon composite is seen in leading edge of the space shuttle where the high temperature resistance is required. The carbon-carbon composites can resist the temperatures upto 3000 .

The advantages of these composites are:

1. Very strong and light as compared to graphite fibre alone.
2. Low density.
3. Excellent tensile and compressive strength.
4. Low thermal conductivity.
5. High fatigue resistance.
6. High coefficient of friction.

The disadvantages include:

1. Susceptible to oxidation at elevated temperatures.
2. High material and production cost.
3. Low shear strength.

Figure 1.12 depicts the range of use temperature for matrix material in composites. It should be noted that for the structural applications the maximum use temperature is a critical parameter. This maximum temperature depends upon the maximum use temperature of the matrix materials.