J. Mater. Sci. Technol. ›› 2019, Vol. 35 ›› Issue (9): 2038-2047.DOI: 10.1016/j.jmst.2019.04.023

• Orginal Article • Previous Articles     Next Articles

Impact of Si addition on high-temperature oxidation behavior of NiAlHf alloys

Jing Jinga, Jian Heabc*(), Hongbo Guoac*()   

  1. a School of Materials Science and Engineering, Beihang University (BUAA), Beijing 100191, China
    b Frontier Research Institute of Innovative Science and Technology, Beihang University (BUAA), Beijing 100191, China
    c Key Laboratory of High-temperature Structural Materials & Coatings Technology (Ministry of Industry and Information Technology), Beihang University (BUAA), Beijing 100191, China;
  • Received:2019-02-17 Revised:2019-03-27 Accepted:2019-04-01 Online:2019-09-20 Published:2019-07-26
  • Contact: He Jian,Guo Hongbo
  • About author:

    1 These authors contributed equally to this work.

Abstract:

Silicon (Si) and reactive elements (REs) like hafnium (Hf) have favorable effects on improving the high-temperature oxidation resistance. To reveal the interaction effect between them, Si with different contents was added into β-NiAlHf alloy in this study. Cyclic oxidation behavior at 1200 °C was investigated. Results show that Si can increase the Hf-rich precipitates and suppress Hf outward diffusion, thus inhibit the RE effect leading to worse oxidation resistance. However, NiAlHf-5Si alloy exhibited a lower oxidation rate and better spallation resistance mainly because of the existence of micro-cracks and Ni2Al3 phases which provided more rapid diffusion paths for Al3+.

Key words: Intermetallic NiAl, Rare earth element, Thermal cycling, Oxidation, Segregation