Optimization of the AM components properties by post-manufacturing treatment

• Establishment of the effective heat-treatment (including HIP) protocols, 
  
• Robust surface treatment processes to increase dynamic properties of the components as well as corrosion resistance, 
  
• Machining protocols for robust removal of the support structures as well as fine machining of the functional surfaces.
  

Five initiatives

1. Tailored heat treatment to optimize AM materials properties
   Post-manufacturing treatment is typically required in order to relieve the stresses, especially important in case of laser sintering, as well as to optimize microstructure. This is usually done by heat treatment procedures, recipes of which are transferred from traditional metallurgy for AM manufactured components. Classical heat treatment processes have to be re-considered to take into account initial state of the as-manufactured AM microstructure. High-performance AM components are typically hot isostatic pressed (HIP) in order to minimize defects such as residual porosity, lack of fusion, etc. Also a novel HIP cycle that includes heat treatment in one process will be applied.
2. Local heat treatment for LMD of superalloy structures
   Focus is on AM of Nickel-based superalloys, involving both powder bed and direct metal deposition techniques and on adopting local heat treatments for pre- and post-build processing. The ability of different local post-heat treatment schedules to locally modify properties of LMD superalloy builds will be evaluated. The influence of various pre-heat treatment protocols on properties of LMD superalloy builds will also be investigated. Both simulation using Gleeble and actual experiments employing a new portable local induction facility are envisioned. 
3. Robust surface treatment processes to optimize AM materials properties
   Focus is placed on the optimization of the surface properties, i.e. the minimization of the surface roughness of the AM components in dependence on process used, process parameters applied as well as base powder characteristic (in collaboration with RA1). High surface roughness of the AM components affects dynamic properties of the parts and hence application requiring improved fatigue performance requires improvement of the surface finish. Focus is also placed on the increased corrosion resistance of AM components that will be selected in dependence on material and application (e.g. by anodization or surface coatings).
4. Robust machining process for AM
   Development of robust machining procedures for efficient removal of the support structures is one of the key prerequisites required for the AM process integration in the manufacturing chain and full process automation. Hence, optimization of the support structures in close collaboration with the RA1 will be performed in order to be able to optimize support structures removal already at the design stage. Machining guidelines will be provided in dependence on material and surface properties required. Fine machining will also be applied in order to improve the surface properties of the AM manufactured components. 
5. Tailoring design and mechanical properties of AM manufactured implants for improved biological response
   This subproject aims at elucidating the relationship between the design, bulk material and manufacturing parameters and its related mechanical properties with the biological response and function in bone anchoring application. In addition, post-manufacturing processes for altering the surface properties are developed for further improving the healing kinetics and bone formation.

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