Download all files (6.52 MB)

Collection

Citation

Description:

Gigacycle fatigue tests were conducted on additively manufactured (AM) Hastelloy X. Individual AM samples manufactured in the Z and X directions were tested at room temperature, and the results were compared with those for conventional samples. The samples were subjected to ultrasonic fatigue testing up to 10^9 cycles and to fatigue testing up to 10^7 cycles. The microstructures of the AM samples consisted of (101) texture that showed high internal plastic strain. The 0.2 % proof stress levels of the AM samples were much higher than those of the conventional samples. Internal fractures were seen in both the AM and the conventional samples at above 10^7 cycles, indicating conventional fatigue limits at 10^7 cycles to be absent in Hastelloy X. The gigacycle fatigue strengths were comparable between the AM and conventional samples and between the Z and X directions. The conventional fatigue test results for the AM samples revealed longer fatigue lives than those for the conventional samples because of the high 0.2 % proof stress. These results show the ultrasonic fatigue test results of the AM samples to be continuously connected to the conventional fatigue test results, unlike the gap seen with conventional samples. Conventional fatigue limits at 10^7 cycles appear to be absent in Hastelloy X, with new fatigue limits possible in the gigacycle region. The internal fracture origins in the AM samples were solidification cracks or the matrix itself, so we conclude that fatigue failure is not caused by porosities or lack of fusion.

Rights:

• Creative Commons BY Attribution 4.0 International
  

Keyword: gigacycle fatigue, additive manufacturing, Hastelloy X, internal fracture, room temperature

Date published: 2026-12-31

Publisher: Informa UK Limited

Journal:

• Science and Technology of Advanced Materials: Methods (ISSN: 27660400) vol. 6 issue. 1 2607165

Funding:

• Amada Foundation AF-2022201-A3

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1080/27660400.2025.2607165

Related item:

Other identifier(s):

Contact agent:

Updated at: 2026-01-31 08:30:04 +0900

Published on MDR: 2026-01-30 17:46:25 +0900