Durability Assessment of Additive Manufactured Compressor Disk Considering Material Defects Distribution

Additive Manufacturing (AM) applications are poised to rapidly expand in aero-engines, providing opportunities to manufacture complex geometries which are unobtainable through traditional manufacturing techniques. The powder based AM process, selective laser melting (SLM), results in susceptibility to defects such as porosity, lack of fusion, and unmelted powder. These random defects often serve as fatigue crack initiation sites, thus influencing fatigue crack initiation and growth behavior. Consequently, the influence of random defects on high cycle fatigue performance for the AM titanium compressor disk is investigated in this study. First, the relationships between the defect area and the fatigue performances involving fatigue limit and the crack propagation threshold are quantified. Second, the effect of defect probability distribution is examined. Finally, the durability analyses on SLM titanium compressor disks in Ti-6A1-4V alloy are performed based on the fatigue life prediction model for defect-containing AM material. Then sensitivity analysis is conducted to determine the critical defect size influencing the fatigue limit and fatigue life.