The Microstructural Degradation of Ni-Based Superalloys with Segregation under the Super-Gravity Condition

• Published in: Metals (Basel ) Vol. 13; no. 2; p. 416
• Main Authors: Yang, Guo, Zhou, Hui, Li, Xueqiao, Wang, Wenshuai, Long, Haibo, Mao, Shengcheng, Zhang, Ze, Han, Xiaodong
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.02.2023
• Subjects: Aging; Degradation; Experiments; Grain boundaries; Heat; Heat resistant alloys; High temperature; microstructural degradation; Microstructure; Ni-based superalloy; Nickel base alloys; segregation; Shape factor; Solid solutions; Solution heat treatment; super-gravity; Superalloys; Temperature effects; Turbine blades; Turbines; Massachusetts; United States > US
• ISSN: 2075-4701; 2075-4701
• DOI: 10.3390/met13020416

The Ni-based superalloy is used as the turbine blade, which is subject to the coupling effect of temperature and super-gravity during service. As the Ni-based superalloys are difficult to become homogenous after using the solid solution heat treatment, a study on morphology and composition distribution of Ni-base superalloys with segregation during microstructural degradation is necessary. This study investigates the microstructure of the ex-service turbine blade and cast samples subjected to the high-temperature centrifugal test. The difference in the size and shape factor of the γ′ phase decreased with the stress caused by the super-gravity condition, indicating a higher magnitude of homogenization degree. The higher stress will also promote the merge of the sub-grain boundaries, leading to a lower density and higher orientational deviation of the sub-grain boundaries.