Abstract of the Offer
UK-based TWI Ltd, an R&D institution, offers joining know-how for additively manufactured metallic components, focused on vacuum brazing and diffusion bonding of laser powder bed fusion (L-PBF) materials such as 316L austenitic stainless steel and aluminum alloys AlSi10Mg, Scalmalloy. The capability supports larger AM assemblies, multi-material structures and complex internal geometries. TWI seeks commercial/service projects with technical assistance, pre-production, subcontracting, manufacture AM components and develop joining solutions.
Description
The technology offer covers AM-to-AM and AM-to-wrought joining process development for metallic parts produced by laser powder bed fusion (L-PBF) and other metal additive manufacturing routes. It addresses size, material and geometry limitations of L-PBF AM process by splitting a component into printable sub-parts and joining them after manufacture. The main functions are to assemble, modify/process and produce high-value metallic complex shaped hardware.
The technical concept combines joint design for AM, surface preparation, thermal cycle selection and joining by vacuum brazing and/or diffusion bonding (uniaxial or hot isostatic pressing). Vacuum brazing uses selected filler materials to create a metallurgical joint by capillary flow at the joint interface. Diffusion bonding joins the prepared faying surfaces under controlled temperature, pressure for a fixed dwell time and in protective atmosphere, with or without interlayers, to achieve a solid-state bonding. The approach is supported by destructive and non-destructive evaluation, metallography, microstructural assessment and functional testing.
Potential applications include additively manufactured heat exchangers, manifolds, propulsion and fluidic parts, structural brackets, complex assemblies with enclosed passages, and multi-material transition components for aerospace, space, power, energy, defence, medical and industrial equipment.
Advantages and Innovations
AM-to-AM joining enables manufacturing of larger or more complex final components than can be built in one AM envelope and joining them. It also enables multi-material or graded assemblies where a single-material AM build is not suitable. Compared with fusion welding, vacuum brazing and diffusion bonding processes can reduce localised parent material melting, residual stresses, heat affected zone (HAZ) and relatively high distortion and can also be more suitable for joining parts with thin walls, lattices and internal channels.
The innovation is the adaptation of established joining science to L-PBF components by considering multiple factors such as surface condition, porosity, residual stress, heat-treatment state and AM microstructure. TWI’s approach integrates joint design, filler/interlayer selection, thermal cycle development and qualification testing to provide an evidence-based joining route for each application.