Glass and glass-ceramics exhibit a huge range of physical properties which can be easily tuned during manufacturing. This makes them popular research subjects for the development of new composite materials. In the aerospace industry, glasses and glass-ceramics are prized for their high heat resistance compared to polymers and conventional aerospace alloys, high strength-to-weight ratio, corrosion resistance and comparatively low cost of manufacturing.1,2
Passenger aircraft, satellites, and rockets place incredible demand on their components. As a result, the aerospace sector poses some of the toughest challenges for materials science. From window coatings to engine parts and turbine blades; the aerospace industry uses some of the strongest, lightest, and most heat resistant materials in the world.
It should come as no surprise, then, that glass and glass-ceramics have a range of aerospace applications. Glasses, silicate-based solids with no long-range atomic order, and glass-ceramics, which are chemically similar to glasses but have some degree of crystallinity, are hugely versatile. A tremendous range of compositions and processing techniques means that glass and glass-ceramics can be tailored to suit a large range of technological applications.
When most people think of glass, they think of windows – so perhaps the most obvious application of glass in the aerospace industry is in airplane windows. But this example serves to illustrate just how demanding aerospace applications can be. While simple silicate glass is perfect for windows down on the ground, it’s too heavy to use for the construction of cabin windows, which are in fact generally made entirely from a polymer such as stretched acrylic. Glass is used to make flight deck windows, but only in the form of a thin layer of protective tempered glass bonded to the surface of a thick layer of polymer.3
Other applications of “ordinary glass” – silicate glass – in aerospace are high silica glass glaze used to coat ceramic tiles that protect space shuttles from burning up during reentry into earth’s atmosphere along with LED lighting and cabin interior features such as mirrors and paneling.
Making Composite Materials with Glasses and Glass Ceramics
The wide versatility of glass and glass ceramics materials are realized when they’re used to create composite materials. Composites are combinations of two or more materials which exhibit properties that differ from the individual components.
Composites are increasing in popularity over conventionally used metals for a number of reasons including their lower weight, better fatigue performance, corrosion resistance, and decreased manufacturing costs. For example, composite materials make up more than 20% of the airframe of the Airbus A380 (first flight in 2005); while the Boeing 787 Dreamliner is 80% composite by volume (first flight in 2009.)4,5
One of the advantages of glass (and glass-ceramics) is the ability to vary its structure and properties through composition and processing – this makes these materials a prime candidate for the development of high-performance composite materials. In aerospace applications, glasses and glass-ceramics can play the part of either filler (e.g. fiberglass-reinforced plastics) or matrix within a composite.6
Aerospace Composites with Glass and Glass Ceramic Fillers
One of the most popular ways of harnessing the properties of glass and glass-ceramics in aerospace is in the form of polymers reinforced with glass or glass-ceramic.6,7 Combining the stiffness and low density of glasses and glass-ceramics with the shear properties of a polymeric matrix can produce a number of high-performance materials with aerospace applications.
One such material in widespread use is Glass and Aluminum Reinforced Epoxy (GLARE). This material not only exhibits excellent fatigue resistance, reducing the frequency of needed inspections, but is both lighter and more corrosion resistant than the aluminum alloys conventionally used in aviation. For these reasons it is used in the Airbus A380, both in the upper fuselage and the leading edges of the stabilizers.8
Glass Fiber-Reinforced Plastic (GFRP) is another example of a polymer-matrix composite material with a glass filler. This material exhibits a particularly high strength-to-weight ratio and is used to make Airbus A320 floor panels among other applications. GFRP exhibits similar properties to Carbon Fiber-Reinforced Plastics but can be produced at a fraction of the cost due to the relatively low cost of glass.9
Thermoplastic Composites (TPCs) offer the ability to produce high-performance components via straightforward and versatile thermoforming. Glass-reinforced TPCs with are used to produce a wide range of aerospace materials.10
Glass and Glass-Ceramic Matrix Composites
Many useful composites can be obtained by employing the “opposite” approach: impregnating an inflexible and low-strength glass or glass ceramic matrix with high-strength and/or high-ductility particulates or fibers.
For example, dispersing aluminosilicate reinforcing fillers throughout a glass-ceramic matrix has produced highly refractive, temperature-resistant materials with low thermal conductivity suitable for use as heat shielding for jet engines.1 Mechanically strong and highly refractive composites can be formed by the dispersal of continuous carbon fibers throughout borosilicate, high-silica, and quartz glasses along with a range of glass-ceramic matrices.
Aerospace Glass from Mo-Sci
Mo-Sci produces several high-specification glasses for aerospace applications. Our engineers can work with you to research and develop custom glasses for aerospace and other demanding environments. Contact us for more information.
References and Further Reading
- Solntsev, S. S. High-temperature composite materials and coatings on the basis of glass and ceramics for aerospace technics. Russ. J. Gen. Chem. 81, 992–1000 (2011).
- Nurhaniza, M., Ariffin, M. K. A., Ali, A., Mustapha, F. & Noraini, A. W. Finite element analysis of composites materials for aerospace applications Related content Finite element analysis of composites materials for aerospace applications. doi:10.1088/1757-899X/11/1/012010
- What Are Airplane Windows Made of? Available at: https://thepointsguy.co.uk/news/what-are-airplane-windows-made-of/. (Accessed: 18th May 2020)
- Aviation – The shape of wings to come | New Scientist. Available at: https://www.newscientist.com/article/dn7552-aviation-the-shape-of-wings-to-come/?ignored=irrelevant. (Accessed: 18th May 2020)
- Composites flying high (Part 1) – Materials Today. Available at: https://www.materialstoday.com/composite-applications/features/composites-flying-high-part-1/. (Accessed: 18th May 2020)
- Boccaccini, A. Glass and glass-ceramic matrix composite materials. J. Ceram. Soc. Japan 109, (2001).
- Dinca, I., Ban, C., Stefan, A. & Pelin, G. Nanocomposites as Advanced Materials for Aerospace Industry. INCAS Bull. 4, 73–83 (2012).
- Quilter, A. Composites in Aerospace Applications.
- Dong Goh, G., Dikshit, V., Arun Prasanth, N. & Guo Liang, G. Characterization of mechanical properties and fracture mode of additively manufactured carbon fiber and glass fiber reinforced thermoplastics. Mater. Des. (2017). doi:10.1016/j.matdes.2017.10.021
- Marsh, G. Reinforced thermoplastics, the next wave? Reinf. Plast. 58, 24–28 (2014).