Thermodynamics analysis and precipitation behavior of fine carbide in K416B Ni-based superalloy with high W content during creep
(Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China)
Abstract: The precipitation behavior of carbide in K416B superalloy was investigated by means of creep measurement and microstructure observation. The results show that nanometer M6C particles discontinuously precipitate in the γ matrix or along the γ/γ′ interface of the alloy during high temperature tensile creep. Thereinto, the amount of fine M6C carbide increases as creep goes on, and the coherent interfaces of M6C phase precipitating from the γ matrix are {100} and {111} planes. The thermodynamics analysis indicates that the solubility of element carbon in the matrix decreases when the alloy is deformed by the axial tensile stress during creep, so as to cause the carbon segregating in the regions of stress concentration and combining with carbide-forming elements M(W, Co), which promotes the fine M6C carbide to precipitate from the γ matrix.
Key words: K416B Ni-based superalloy; M6C carbide; stress inducement; thermodynamics analysis