J. Mater. Sci. Technol. ›› 2015, Vol. 31 ›› Issue (2): 143-147.DOI: 10.1016/j.jmst.2013.12.019

• Orginal Article • Previous Articles     Next Articles

Effect of Mo Addition on Microstructural Characteristics in a Re-containing Single Crystal Superalloy

X.G. Liu1, L. Wang1, L.H. Lou1, J. Zhang1, 2   

  1. 1 Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China; 2 Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
  • Received:2013-10-31 Online:2015-02-20 Published:2015-07-23
  • Contact: Corresponding author. Prof., Ph.D.; Tel.: +86 24 23971196; Fax: +86 24 23971712.E-mail address: jianzhang@imr.ac.cn (J. Zhang).
  • Supported by:
    The authors gratefully acknowledge the Shanghai Synchrotron Radiation Facility (SSRF) and the financial support of the project from the National Basic Research Program of China (No. 2010CB631201), and the National High Technology Research and Development Program of China (No. 2012AA03A511 and No. 2012AA03A513).

Abstract: The effect of Mo addition on microstructural characteristics of a nickel-base single crystal superalloy containing 4 wt% Re was investigated. The γ/γ′ partitioning ratios determined by energy dispersive spectrometer attached to a transmission electron microscope showed that the addition of Mo enhanced the partitioning of Re, W and Cr in the γ matrix while decreased the concentration of Ta in the matrix. Synchrotron radiation diffraction was adopted to measure the γ/γ′ lattice misfit at room temperature. The results indicated that Mo addition changed the γ/γ′ lattice misfit towards larger negative as well as increased the tetragonal distortion of the γ lattice. Additionally, Mo addition led to microstructural instability and altered the precipitation behavior of topologically close-packed phases during 1100 °C exposure. Instead of precipitating directly from the matrix, the μ phase was observed to be converted from the σ phase which precipitated preferentially as a metastable intermediate in the alloy with high Mo content.

Key words: Superalloy, Molybdenum, Microstructure, Partitioning behavior, Lattice misfit