Fabrication and functional properties of additively manufactured NiTi lattice structures using adaptive scanning strategies

Near-equiatomic NiTi-alloys are attractive materials for medical applications due to their functional properties (pseudoelasticity). However, most of the manufacturing steps needed for processing of NiTi are challenging. Thus, laser beam melting (LBM) was used and identified as a suitable method for the fabrication of a wide range of complex NiTi structures with low impurity pick up and good functional properties. Besides obtaining as-built parts with pronounced shape-recovery, efforts have been made to improve the quality of the processed specimens (e.g. accuracy). In our work, we demonstrate that delicate NiTi lattice structures can be manufactured on a conventional LBM machine using point scanning strategies. Process parameters and the type of point exposure have been optimized to obtain struts (below 200 microns) with high evenness and smooth surfaces. Due to this reason, the use of point scanning strategies is a promising approach for LBM of NiTi lattices with improved mechanical properties.