Some Behaviors of Phosphorus in Several Typical Superalloys
The effect of phosphorus in some typical wrought superalloys including IN718, GH761 and GH4133 has been studied. Phosphorus was not dissolved in the γ matrix of superalloys and was segregated in the residual liquids seriously during solidification, and the solidification of the alloys added with phosphorus was always finished by the precipitation of a phosphorus bearing phase. Two factors controlling the segregation tendency of a minor element were determined, one is the solubility of the element in the matrix, another is the precipitation temperature of a phase in which the element is absorbed. The detrimental effect of phosphorus on the solidification could be eliminated by a proper homogenization treatment. Phosphorus improved the stress rupture properties of the alloys with a fine grain structure. By combining the grain refinement with phosphorus addition, the properties of GH761 alloy was improved efficiently.
T. Chandra, K. Tsuzaki, M. Militzer , C. Ravindran
W. R. Sun et al., "Some Behaviors of Phosphorus in Several Typical Superalloys", Materials Science Forum, Vols. 539-543, pp. 3053-3058, 2007