Effect of carbon addition on the creep properties in a Ni-based single crystal superalloy

Effect of minor carbon addition on the creep properties of an experimental Ni-based single crystal superalloy has been investigated. Three alloys with different level of carbon addition were subjected to creep tests of 871 °C/552 MPa and 1038 °C/172 MPa. With the increase of carbon addition, the creep properties of alloys presented different trends. Detailed microstructural analysis have revealed that precipitation of M6C carbide and reduction of casting pores are beneficial to the creep properties, and the improvement at high temperature and low stress is stronger than that at low temperature and high stress. The larger γ′ particle, eutectic and MC carbide are the weakening factors for creep properties; however, the weakening effect at high temperature and low stress is weaker than that at low temperature and high stress.