Creep and Stress Relaxation Anisotropy of a Single-Crystal Superalloy
2014 (English)In: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 45, no 5, 2532-2544 p.Article in journal (Refereed) Published
In this study, the TMF stress relaxation and creep behavior at 1023 K and 1223 K (750 °C and 950 °C) have been investigated for a Ni-based single-crystal superalloy. Specimens with three different crystal orientations along their axes were tested; 〈001〉, 〈011〉, and 〈111〉, respectively. A highly anisotropic behavior during TMF stress relaxation was found where the 〈111〉 direction significantly shows the worst properties of all directions. The TMF stress relaxation tests were performed in both tension and compression and the results indicate a clear tension/compression asymmetry for all directions where the greatest asymmetry was observed for the 〈001〉 direction at 1023 K (750 °C); here the creep rate was ten times higher in compression than tension. This study also shows that TMF cycling seems to influence the creep rate during stress relaxation temporarily, but after some time it decreases again and adapts to the pre-unloading creep rate. Creep rates from the TMF stress relaxation tests are also compared to conventional constant load creep rates and a good agreement is found.
Place, publisher, year, edition, pages
Springer, 2014. Vol. 45, no 5, 2532-2544 p.
Single-crystal superalloy, thermomechanical fatigue, creep, stress relaxation, deformation mechanism
Other Materials Engineering
IdentifiersURN: urn:nbn:se:liu:diva-89949DOI: 10.1007/s11661-014-2198-0ISI: 000334428000026OAI: oai:DiVA.org:liu-89949DiVA: diva2:610547
On the day of the defense data of the Licentiate Thesis the status of this article was Manuscript.2013-03-122013-03-122016-05-19Bibliographically approved