Effect of Primary Deoxidation Products of Al₂O₃, ZrO₂, Ce₂O₃ and MgO on TiN Precipitation in Fe–10mass%Ni Alloy

Abstract

Effect of Al₂O₃, ZrO₂, Ce₂O₃ and MgO particles with mean diameter of 0.8 to 1.5 μm on the precipitation of TiN during solidification and holding at 1 400°C has been studied in an Fe–10mass%Ni alloy. The values for the number of particles per unit area, N_A, and the mean diameter, d_A, of TiN and TiN+M_xO_y(M=Al, Zr, Ce, and Mg) particles have been measured as a function of initial contents of Ti (50 to 990 mass ppm) and N (200 to 290 mass ppm), and holding time (0 and 60 min). The N_A values of the TiN+MgO particles are considerably higher than those of the TiN+M_xO_y(M=Al, Zr, and Ce) particles, while the d_A values of the former particles, which are found to be independent of solidification mode, are smaller than those of the latter particles. The d_A values of TiN and TiN+M_xO_y(M=Al, Zr, and Ce) particles in dendritic solidification are smaller than those in nondendritic one, whereas an opposite trend is observed with respect to the N_A values. The d_A values of the TiN and TiN+M_xO_y particles were found to remain unchanged, but the N_A values tended to slightly increase with holding time.