Effects of Ru on the microstructure and phase stability of a single crystal superalloy

• Published in: International journal of minerals, metallurgy and materials Vol. 19; no. 11; pp. 1004 - 1009
• Main Authors: Shi, Zhen-xue, Li, Jia-rong, Liu, Shi-zhong
• Format: Journal Article
• Language: English
• Published: Springer Berlin Heidelberg University of Science and Technology Beijing 01.11.2012; Springer Nature B.V; Science and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,Beijing 100095,China
• Subjects: Aging (metallurgy); Alloying elements; Alloys; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Coarsening; Composites; Corrosion and Coatings; Directional solidification; Glass; Materials Science; Metallic Materials; Metallurgy; Microstructure; Natural Materials; Nickel base alloys; Phase stability; Phases; Single crystals; Superalloys; Surfaces and Interfaces; TCP (protocol); TCP相; Thin Films; Tribology; X射线光谱仪; 单晶高温合金; 合金元素; 微观结构; 相稳定性; 超耐热合金; 透射电子显微镜; ruthenium; nickel alloys; microstructure; single crystals; superalloys; phase stability
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-012-0661-8

Two experimental single crystal superalloys, the Ru-free alloy and the Ru-containing alloy with [001 ] orientation, were cast in a directionally solidified furnace, while other alloying element contents were kept unchanged. The effects of Ru on the microstructure and phase stability of the single crystal superalloy were investigated, y＇ directional coarsening and rafting were observed in the Ru-free alloy and Ru-containing alloy after long-term aging at 1070~C for 800 h. Needle-shaped o topologically close packed （TCP） phases precipitated and grew along the fixed direction in both the alloys. The precipitating rate and volume fraction of TCP phases decreased significantly by adding Ru. The compositions ofy and y＇ phases measured using an energy-dispersive X-ray spectroscope （EDS） in transmission electron microscopy （TEM） analysis showed that the addition of Ru lessened the partition ratio of TCP forming elements, Re, W and Mo, and decreased the satu- ration degrees of these elements in y phase, which can enable the Ru-containing alloy to be more resistant to the formation of TCP phases. It is indicated that the addition of Ru to the Ni-based single crystal superalloy with high content of the refractory alloying element can enhance phase stability.