Mon, 08 February, 2021
TWI intends to launch a Joint Industry Project (JIP) to further develop refractory metals using additive manufacturing.
Refractory metals (tungsten, molybdenum, niobium and tantalum) and their alloys are well known for possessing extremely high temperature properties and as a result, are ideal candidates for high temperature applications across multiple industries. However, whilst they offer high thermal and electrical conductivity combined with high wear resistance, they are well known to be difficult to process, which prevents widespread utilisation.
Due to their extremely high melting points and ease of oxidation, refractory metals often need supplying as a powder for part manufacture, which limits fabrication methods. Additionally, their high hardness makes machining of manufactured parts extremely difficult. These challenges are overcome with the use of additive manufacturing (AM) techniques, such as powder bed fusion (PBF-LB) and directed energy deposition (DED-LB). By utilising material only where it is needed, AM can produce individual metal components with complex geometries layer-by-layer, without the need for part specific tooling or machining.
However, challenges still remain in AM due to the high melting point, high thermal conductivity and brittle nature at room temperature of these materials. This can result in parts with cracked/porous microstructures.
TWI has already made significant developments in processing some of these refractory metals using AM and has measured repeatable and consistent densities (>98%), alongside some interesting characteristic observations in thin walls e.g. flexibility.
A Joint Industry Project would provide the opportunity to continue development in this area, to keep pace with increasing interest from industry to remove constraints and expand the design space for high-strength refractory parts.
For more information on this project opportunity and its benefits to your organisation, please contact Amanda Allison: amanda.allison@twi.co.uk