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pISSN : 1598-706X / eISSN : 2288-8381


한국주조공학회지 (26권4호 184-190)

An Artificial Inclusion Seeding Methodology for Fatigue Design of Aerospace Ti Castings

인공개재물 이식법을 통한 항공기용 티타늄 주물의 피로설계

Paul, L. Ret, Yong-Kuk Park*, Jin-Gon Kim

A ir Force Research Lab, Wright-Patterson A ir Force Base, *Catholic University o f Daegu


Presence of inclusions in Ti castings imparts detrimental effects on the mechanical performance of castings. However, actual inclusions do not occur very frequently and they are difficult to locate. As a result, acquirement of specimens for mechanical tests and thus in-depth research of the adverse influence of inclusions are challenging. To address this problem, artificial inclusion seeding methodology is developed to emulate actual inclusions in Ti investment castings. Firstly, to validate that this new methodology does not result in inherent mechanical property degradation, Ti specimens with machined, backfilled and HIPed holes are produced and compared to control (unaltered), cast Ti material. Fatigue test results indicate that this 'machine-and-HIP methodology without seeding' does not result in any fundamental mechanical property alteration, which would bias ensuing comparative results. Secondly, based on this result, validation of the artificially seeded inclusions being equivalent to 'as cast' inclusions is performed by comparing their fatigue behaviors. Test specimens created by the novel artificial inclusion seeding methodology are equivalent to Ti casting specimens containing actual cast-in inclusions, and an adverse effect of inclusions in investment castings is confirmed.


Ti-6A1-4V, Hard alpha inclusion, Artificial inclusion seeding methodology, Hot isostatic pressing(HIP), Fatigue test, Fatigue life.