Summary: The Impact of Composites on Materials Research
Composites had a direct impact on materials technology and indirectly reoriented materials science and engineering.
How composites changed materials technology:
Materials by design. A distinct advantage of composites, over other materials, is the flexibility of design. By using many combinations of resins and reinforcements, one can design a composite to meet specific strength requirements. Advanced composites for aerospace industry are thus tailored to perform a specific set of functions in a specific environment. Composites opened up the era of materials by design when high modulus continuous fibers such as aramid or carbon fibers were introduced. They are not randomly oriented like short fibers, but carefully aligned into a unidirectional tape. Making such composites is a laborious process with many steps, the endproduct is more expensive than the standard materials used in mass-production. However they offer higher performances for a specific use.
Crossing Boundaries. Because they associate various families of traditional materials in one single structure, composites encouraged the hybridization of independent industrial traditions. Glass companies and textile industry began to cooperate on the production of fiberglass in the 1950s. Glass manufactures and chemical companies, and also metallurgy and ceramics technologies, had to learn from each other to manufacture composites.
Systems approach. The technology of composites helped develop a systems approach in materials research. In order to design composites with more than the sum of the properties of their individual components, a parallel synergy should be created between the various experts involved in the design of the composite material and a cooperation between customers and suppliers.
How composites changed MSE:
Performances and Process. Whereas metallurgy and solid state physics had focused the attention of materials scientists on the relation between structure and properties, performance and process entered the game with R&D on composites (together with R&D on electronic materials). High performances are the driving force in advanced composites. And processes are so important in automotive industry that materials are labeled after their fabrication process rather than by their composition. Composites undoubtedly generated a new way of thinking.
Surface and Interfaces. Composites turned the attention of materials scientists to the interface between two phases. Because the mechanical properties of heterogeneous structure depend upon the quality of the interface between the reinforcing fiber and the matrix, interfaces and srufaces became a prime concern of materials science and technology. Surface science thus emerged as a new field of research. As Bernhardt Wuensch emphasized in a recorded discussion: "worrying about interfaces was the beginning of composites and the beginning of Materials Science and Engineering" (a transcript of this discussion is in preparation).
Biomimetism. Wood and bones are natural composites whose functions and properties challenge the most advanced materials designed by human art. Biomimetism thus became one of the favorite strategies to design molecular and nanocomposites.