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

近年来，通过激光粉末床熔合（L -PBF）增材制造（AM）制造的镍钛诺（NiTi）形状记忆合金引起了人们的广泛关注，与传统制造工艺相比，它可以生产出设计复杂度高的镍钛诺零件。避免在L期间出现缺陷-PBF对于生产高质量镍钛诺零件至关重要。在这项研究中，可以协同使用预测熔池尺寸和缺陷形成标准的分析模型来开发加工图，以证明形成缺陷的边界条件，例如球形，锁孔引起的孔洞和缺乏熔合。实验验证表明，该方法可以提供准确的估计值并指导无缺陷镍钛诺合金的可制造性。此外，对裂纹形成现象进行了实验分析，结果表明线能量密度较低（E _l）的选择应避免在优化的工艺窗口中出现裂纹。根据模型预测和实验校准，成功制备了相对密度超过99％的镍钛诺样品。