Microstructure and Mechanical Properties of a Cobalt-Based Superalloy Used for Nuclear Power Station

Abstract:

The microstructure and mechanical properties of a Co-Cr-W-Mo superalloy used for the driving mechanism of nuclear power station were investigated. This alloy was strengthened by W and Mo elements and carbides for high hardness, and an excellent wear resistance was achieved by the high content of carbides. Also, this alloy was of excellent hot-corrosion resistance due to the addition of 29 wt. % Cr. The as-cast alloy was equiaxed, and consisted mainly of γ-Co solid solution, γ/M₇C₃ eutectics and Cr-rich M₇C₃ carbides. The Rockwell hardness was up to 37 - 40. The alloy presented high tensile strength, and the fractography of tensile ruptured specimens was characterized obviously by the interdendritic fracture.

• Periodical: Materials Science Forum (Volume 816)
• Pages: 529-533
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.816.529
• Online since: April 2015
• Authors: Yong An Guo, Chang Shuai Wang, Xue Zhi Qin, Wan Hui Lai, Lan Zhang Zhou
• Keywords: Cobalt-Based Superalloy, Driving Mechanism, Hardness, Mechanical Property, Microstructure Property, Nuclear Power Station

References

[1] R.K. Zhao, Sustainable development of Chinese nuclear power, Engineering Science. 2 (2000) 33-41.

[2] Q.F. Yang, W.G. Zhang, Situation and strategy of the present nuclear material and technology, China Materials (2004) 115-121.

[3] W.G. Zhang, Challenges in material for the fourth generation nuclear power, Corrosion & Protection, Vol. 27 (2006) 541-543.

[4] Q.P. Shen, Overview of the main materials of key equipment for non-dynamic series of nuclear power plant, New Achievements of forum on technology innovation, enterprise development, and new material and equipment Manufacture (2012) 154-164.

[5] J.T. Guo, Materials Science and Engineering for Superalloys, Science Publications, Beijing (2008).

[6] H. Celik, M. Kaplan, Effects of silicon on the wear behaviour of cobalt-based alloys at elevated temperature, Wear 257 (2004) 606–611.

DOI: 10.1016/j.wear.2004.03.008

[7] V. Kuzucu, M. Ceylan, H. Celik, I. Aksoy, An investigation of stellite-6 alloy containing 5. 0 wt. % silicon, Journal of Materials Processing Technology Vol. 79 (1998) 47-51.

DOI: 10.1016/s0924-0136(97)00452-4

[8] R. Liu, S.Q. Xi, S. Kapoor, X.J. Wu, Effcts of chemical composition on solidification, microstructure and hardness of Co-Cr-W-Ni and Co-Cr-Mo-Ni alloy systems, IJRRAS Vol. 2 (2010) 110-122.

[9] C.X. Shi, China Superalloys Handbook, Standards Press of China, Beijing (2012).