Mechanical and geometrical characterization of additively manufactured INCONEL® 718 porous structures for transpiration cooling in space applications

The need for ever increasing process temperatures during combustion in space engines and gas turbines to increase efficiency requires the use of thermally resistant materials and novel cooling solutions. For the improved cooling of thermally highly stressed components, the technology of transpiration cooling, in which a cooling medium flows through a porous structure, has been known for a long time. Additive manufacturing and, in particular, laser powder bed fusion (LPBF) offers great potential for the near-net-shape production of porous structures compared to complex conventional manufacturing. In this contribution, porous structures were manufactured and the process parameters were optimized to increase the quality of the pores. The study discloses an adapted exposure parameter set for the improved fabrication of cylindrical pores in an INCONEL® 718 material and the associated mechanical properties of porous and dense components.