Advanced AM Materials
The main objective of additive manufacturing technology is to allow the development of high-performance, more advanced parts and components. The creation of new and more sophisticated materials is therefore a crucial factor in the advancement of AM technologies. Developing and refining advanced 3D printing materials allows faster processing and more complex parts to be created; at the same time, the advancement of 3D printing processes depends on refining ever more advanced materials for higher-performance parts. In general, by means of advanced materials, the industry refers to all those materials which are at the cutting edge of material science production. These include composites, high-performance polymers, high- temperature metals (refractory), and ceramics.
Composites used in AM are mainly composites of carbon fiber, glass fiber, or Kevlar inside a thermoplastic matrix (unlike conventional composites in a thermoplastic matrix). They can be made available as powders, pellets, or filaments and typically used as chopped fibers (although technologies capable of producing continuous fiber composites are in development). Nevertheless, the concept of composites is incredibly broad and can be expanded to include metal composites, polymer-ceramic composites, and even carbon-ceramic composites.
Advanced AM materials also include high-performance polymers, in particular PAEK family polymers such as PEEK, PEKK, and PEI (ULTEM). These are high-temperature, high-stress thermoplastics that melt at temperatures of 400°C. The ability to print 3D using these materials for a number of medical and metal- replacement industrial applications is expected to significantly boost the demand for additive manufacturing.
Ceramics is also a very large family of materials that can range from cement and clay to diamonds. Advanced 3D ceramic printing materials are primarily represented by technical ceramics such as alumina (aluminum oxide), zirconia (zirconium oxide), and other advanced ceramic materials based on silicon. These materials offer almost unparalleled properties in terms of heat resistance, strength, and light weight, but they are difficult to shape using traditional technologies. This is why they are considered especially important for the future of AM.
Advanced materials in metal additive manufacturing include mainly refractory metals (as well as certain metal composites). These are extremely high-temperature resistant metals that can withstand temperatures in excess of 4000°C. The list of 3D printable refractory metals (mainly powder-bed fusion processes) includes tungsten, niobium molybdenum, and other metals that can greatly benefit from the geometrical possibilities provided by AM. Finally, 3D printing soon became a critical technology for the creation of completely new categories of materials. Which involve applications involving graphene and graphene allotropes (the different forms that graphene may produce, such as nanotubes or buckyballs), ultra-light or ultra-dark or even so-called 4D materials.
Broadly speaking, these are materials that can be programmed to perform a particular action after they have been used for the manufacture of an object. They therefore add the “4th dimension” in that the objects continue to evolve over time after the 3D printing process has been completed. For example, shape-memory materials that can turn back to previous states and shapes, or auto-assemble structures that change shape as they heat up or cool down. The list goes on and on, and in many cases 3D printing has proved to be of key importance in allowing rapid testing of new theories in material behavior.
