Page 249 - Manufacturing Engineering and Technology - Kalpakjian, Serope : Schmid, Steven R.

228 Chapter 9 Composite Materials: Structure, General Properties, and Applications

FIGURE 9.l0 Examples of metal-matrix composite parts.
Source: Courtesy of Metal Matrix Cast Composites, LLC.

TABLE 9.3
Metal-matrix Composite Materials and Applications
Fiber Matrix Applications
Graphite Aluminum Satellite, missile, and helicopter structures
Magnesium Space and satellite structures
Lead Storage-battery plates
Copper Electrical contacts and bearings
Boron Aluminum Compressor blades and structural supports
Magnesium Antenna structures
Titanium ]et-engine fan blades
Alumina Aluminum Superconductor restraints in fission
power reactors
Lead Storage-battery plates
Magnesium Helicopter transmission structures
Silicon carbide Aluminum, titanium High-temperature structures
Superalloy (cobalt base) High-temperature engine components
Molybdenum, Superalloy High-temperature engine components
tungsten

EXAMPLE 9.3 Aluminum»matrix Composite Brake Calipers

One of the trends in automobile design and manufac- and rotor is highly constrained.
ture is the increased push towards lighter weight A new brake caliper was designed using an
designs in order to realize improved performance aluminum alloy locally reinforced with precast
and/or fuel economy. This trend can be seen in the composite inserts using continuous ceramic fiber. The
development of metal-matrix composite brake fiber is a nanocrystalline alumina with a diameter of
calipers. Traditional brake calipers are made from 10 to 12 pm and a fiber volume fraction of 65%.
cast iron and can weigh around 3 kg each in a small The fiber and material properties are summarized in
car and up to 14 kg in a truck. The cast-iron caliper Table 9.4. Finite element analysis confirmed the
could be redesigned completely, using aluminum to placement and amount of reinforcement, leading to a
achieve weight savings, but that would require a larg- design that exceeded minimum design requirements
er volume, and the space available between the wheel and that matched deflections of cast-iron calipers in a