The Impact of High‐Productivity Processing on the Fatigue Failure of an Additive Manufactured Superalloy HAYNES 282

The elevated temperature low cycle fatigue life of additively manufactured HAYNES 282 superalloy from conventional 40 µm layer thickness process parameters was compared with that of high‐productivity 80 µm layer thickness process parameters. Wrought 282 alloy was also tested in parallel for comparison. The 40 µm process parameters produced fatigue life between 1400 and 1700 cycles to failure, the 80 µm process parameter specimens failed after ≈1200 cycles, and the wrought alloy reached 1350 cycles to failure. Microstructure investigations did not reveal systematic differences in phase constituents or grain structure between 40 and 80 µm processed 282 alloy. While both process parameters produced porosity of less than 0.05% by volume, high‐resolution X‐ray computed tomography showed the occurrence of large aspect ratio lack of fusion defects in the 80 µm material. These defects were also identified on fracture surfaces and could be related to the accelerated initiation and propagation of cracks, especially when oriented perpendicular to the load axis in samples built parallel to the building direction. The results emphasize the criticality of seemingly minor variations in defect characteristics on performance in cyclic loading conditions for high strength alloys.