Precipitation behavior of TiN in Fe-10mass%Ni alloy during solidification and isothermal holding at 1 400 degrees C

The precipitation of TiN during solidification and holding at 1 400 degrees C has been studied in an Fe-10mass%Ni alloy as a function of initial conten ts of Ti and N and holding time. Dendritic and nondendritic (globular cell) zones are observed under the condition of the undercooling of 5 to 35 degr eesC. The number of particles per unit area, N-A, in nondendritic zone is s ignificantly smaller than that in dendritic zone and the N,values in both z ones Increase with holding time. The values for mean particle diameter, (d) over bar (A), remain unchanged in dendritic zone with holding time, while the (d) over bar (A) values decrease with holding time in nondendritic zone . In dendritic and nondendritic zones, the degree of precipitation of TiN p articles increase with increasing area fraction of solid, f(S), and the deg ree of precipitation depends on initial contents of Ti and N. The (d) over bar (A) value in nondendritic zone, which is independent of f(S), is larger than that in dendritic zone at zero holding time for a given initial conte nt.