J Mater Sci Technol ›› 2011, Vol. 27 ›› Issue (10): 899-905.

• High Temperature Structural Materials • Previous Articles     Next Articles

Measurements of γ/γ´ Lattice Misfit and γ´ Volume Fraction for a Ru-containing Nickel-based Single Crystal Superalloy

X.P. Tan1), J.L. Liu1), X.P. Song2), T. Jin1), X.F. Sun1), Z.Q. Hu1)   

  1. 1) Superalloy Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
    2) Analysis and Testing Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
  • Received:2010-12-14 Revised:2011-03-16 Online:2011-10-31 Published:2011-10-24
  • Contact: Tao JIN
  • Supported by:

    the National Basic Research Program (973 Program) of China under grant No. 2010CB631200, and the National Natural Science Foundation of China (NSFC) under grant No. 50931004

Abstract: A conventional X-ray diffractometer has been used to determine the γ/γ´ lattice misfit and γ´  volume fraction for a Ru-containing nickel-based single crystal superalloy at room temperature. The rocking curve was used to characterize the distribution of subgrains. The diffraction peaks obtained by ω-2θ scan were used to determine the γ/γ´ lattice misfit and γ´ volume fraction. A three peaks fitting model was proposed. The peak fitting results are in good agreement with the model. The X-ray diffraction results indicate that the nickel-based single crystal superalloy was not a perfect monocrystalline material, which is comprised of many subgrains; and each subgrain also consists of large numbers of mosaic structures. In addition, two anomalous reflection
phenomena were found during the experiment and discussed with respect to their occurrence and impact on the measurement. The experimental results show that the γ/γ´ lattice misfit and γ´ volume fraction will be various at the different regions of its dendritic microstructure. The average γ/γ´ lattice misfit and γ´ volume fraction of the experimental alloy are approximately -0.2% and 70%, respectively. Furthermore, the γ´ volume fraction calculated by atom microprobe (AP) data is also basically consistent with the experimental results.

Key words: Nickel-based superalloy, Microstructure, X-ray diffraction, Lattice misfit,   γ´, volume fraction