Distortion and printability of stent structures in laser powder bed fusion processing of NiTi alloys

Self-expandable NiTi stents are extensively used to treat coronary or peripheral arterial disease due to their remarkable biocompatibility and superelasticity. However, the feasibility of fabricating patient-specific NiTi stents through laser powder bed fusion (L-PBF) is yet to be determined. Two supposedly optimized energy density values (low and high) were used to investigate the residual stresses evolution and in-process distortion of the stents. Numerical predictions and experimental results revealed that employing an energy density of 56 J/ mm3 results in an acceptable level of in-process distortion and ensures the manufacturability of dense austenitic stent structures via L-PBF. However, fabricated stents suffer from low dimensional accuracy and a rough surface, which necessitates future studies to overcome these obstacles.