Using Thermo-Calc thermodynamic software combined with the nickel-based database

the possible equilibrium precipitates in FGH96 superalloys containing 0.003% N and in FGH96 superalloys without N were calculated

and the solidification simulation of FGH96 superalloy has been made based on the Scheil-Gulliver solidification model.The effects of N on precipitate in FGH96 superalloy have been investigated by comparing the calculated results of two kinds of superalloys.The result show that

nitrogen content shows a great effect on the primary carbide phase MC+M（C

N） with a very limited contribution on the other phases;carbonitride M（C

N） mainly containing Ti and N is precipitated from liquid phase above liquidus temperature in FGH96 superalloy with a little N

while MC-type carbide is precipitated from residual liquid phase when the mass fraction of solid phase reaches 70% in FGH96 superalloy without N.It can be proposed by the result of thermodynamic calculation

SEM

and EDS that the primary carbonitride M（C

N） mainly as TiN is preferred to precipitate from the liquid FGH96 superalloy containing N

and then MC-type carbides are precipitated on the surface of M（C

N）

forming primary carbides as TiN nuclei.