Predictive analytical modelling and experimental validation of processing maps in additive manufacturing of nitinol alloys

Nitinol (NiTi) shape memory alloys fabricated by Laser Powder Bed Fusion (L-PBF) Additive Manufacturing (AM) have attracted much attention in recent years, as compared with conventional manufacturing processes it allows to produce parts high design complexity. Avoidance of defects during L-PBF is crucial for the production quality parts. In this study, analytical models predicting melt pool dimensions and defect formation criteria were synergistically used develop processing maps demonstrating boundary conditions such defects, balling, keyhole-induced pores, lack fusion. Experimental validation has demonstrated that method can provide an accurate estimation guide manufacturability defect-free alloys. Moreover, crack phenomena experimentally analysed, which showed a low linear energy density (El) should be chosen avoid cracks optimized process windows. Based on model predictions experimental calibrations, samples relative more than 99% successfully fabricated.