1.1 What is a composite material?
Composite materials are materials in which a homogenous matrix is reinforced by a stronger and stiffer constituent that is usually fibrous but may have a particulate or other shape (web.mit.edu). They are produced when two or more materials or phases are used together to give a combination of properties that cannot be attained otherwise. For example steel reinforced concrete, plywood and fibre glass.
1.2 What is a Ceramic Matrix Composite (CMC)?
CMCs are a subgroup of composite materials. They consist of ceramic fibres embedded in a ceramic matrix, thus forming a ceramic fibre reinforced ceramic (CFRC) material.
1.2.1 Properties of CMCs There are a wide range of sorts of CMCs. They are usually classified in …show more content…
During fracture, cracks arise in the matrix and are deflected at the fibres, thereby increasing the fracture surface and elongation at break. Table 1 Properties of CMCs (Ceramic Applications, 2013)
1.2.2 Uses of CMCs
CMCs are used in many high temperature processes. They have a very high thermal shock and creep resistance, which enables designs with large mechanical and thermal loads.
Ox/Ox hot gas valves are used to control the gas flow in gas fired high temperature furnaces. Compared to metallic valves, the service life of the CMC components is much longer and over-compensates their higher purchasing costs.
CMC components are used as batch carriers in metal hardening; the C/C grids have a small heat capacity hence thus reducing energy consumption and allowing fast heating and cooling cycles.
They are used to make flame tubes, heat exchangers, protective tiles and various high temperature …show more content…
If weight-adjusted properties not relevant, steel and other traditional materials may work fine at lower cost.
Anisotropy and other “special” features are advantageous in that they provide a great deal of design flexibility, but the flip side of this coin is that they also complicate the design. The well-known tools of stress analysis used in isotropic linear elastic design must be extended to include anisotropy, for instance, and not all designers are comfortable with these more advanced tools.
Even after several years of touting composites as the “material of the future,” economies of scale are still not well developed. As a result, composites are almost always more expensive – often much more expensive – than traditional materials, so the designer must look to composites’ various advantages to offset the extra cost. During the energy-crisis period of the 1970’s, automobile manufacturers were so anxious to reduce vehicle weight that they were willing to pay a premium for composites and their weight advantages. But as worry about energy efficiency diminished, the industry gradually returned to a strict lowest-cost approach in selecting materials. Hence the market for composites in automobiles returned to a more modest rate of
Composite materials are materials in which a homogenous matrix is reinforced by a stronger and stiffer constituent that is usually fibrous but may have a particulate or other shape (web.mit.edu). They are produced when two or more materials or phases are used together to give a combination of properties that cannot be attained otherwise. For example steel reinforced concrete, plywood and fibre glass.
1.2 What is a Ceramic Matrix Composite (CMC)?
CMCs are a subgroup of composite materials. They consist of ceramic fibres embedded in a ceramic matrix, thus forming a ceramic fibre reinforced ceramic (CFRC) material.
1.2.1 Properties of CMCs There are a wide range of sorts of CMCs. They are usually classified in …show more content…
During fracture, cracks arise in the matrix and are deflected at the fibres, thereby increasing the fracture surface and elongation at break. Table 1 Properties of CMCs (Ceramic Applications, 2013)
1.2.2 Uses of CMCs
CMCs are used in many high temperature processes. They have a very high thermal shock and creep resistance, which enables designs with large mechanical and thermal loads.
Ox/Ox hot gas valves are used to control the gas flow in gas fired high temperature furnaces. Compared to metallic valves, the service life of the CMC components is much longer and over-compensates their higher purchasing costs.
CMC components are used as batch carriers in metal hardening; the C/C grids have a small heat capacity hence thus reducing energy consumption and allowing fast heating and cooling cycles.
They are used to make flame tubes, heat exchangers, protective tiles and various high temperature …show more content…
If weight-adjusted properties not relevant, steel and other traditional materials may work fine at lower cost.
Anisotropy and other “special” features are advantageous in that they provide a great deal of design flexibility, but the flip side of this coin is that they also complicate the design. The well-known tools of stress analysis used in isotropic linear elastic design must be extended to include anisotropy, for instance, and not all designers are comfortable with these more advanced tools.
Even after several years of touting composites as the “material of the future,” economies of scale are still not well developed. As a result, composites are almost always more expensive – often much more expensive – than traditional materials, so the designer must look to composites’ various advantages to offset the extra cost. During the energy-crisis period of the 1970’s, automobile manufacturers were so anxious to reduce vehicle weight that they were willing to pay a premium for composites and their weight advantages. But as worry about energy efficiency diminished, the industry gradually returned to a strict lowest-cost approach in selecting materials. Hence the market for composites in automobiles returned to a more modest rate of