Abstrait

Phase equilibria in the Co-Ti-Zr system at 1023K

G.J.Zhou,Y.Lou, X.S.Li

The isothermal section of the Co-Ti-Zr ternary system at 1023K has been investigated by means of diffusion triple together with electron probe microanalysis technique. Series of tie lines and tie-triangles have been determined and the isothermal section at 1023K has been established. 17 three-phase equilibria were observed, namely Co3Ti+Co2Zr+Co2Ti(h), Co2Zr+Co2Ti(h)+Co2Ti(c), Co3Ti+Co+Co2Zr, Co2Zr+CoTi+Co2Ti(c), Co2Zr+CoTi+CoTi2, CoTi2+â(Ti,Zr)+M, â(Ti)+á(Ti)+â(Ti,Zr), â(Ti,Zr)+CoTi2+â(Ti), Co2Zr+M+CoTi2, Co2Zr+N+ M, Co23Zr6+Co2Zr +Co, Co2Zr+CoZr+CoZr2, Co2Zr+N+CoZr2, CoZr2 +N+â(Ti,Zr), M+N+â(Ti,Zr), CoZr2+â(Ti,Zr)+CoZr3 and CoZr3+ â(Ti,Zr)+á(Zr). The solid solubility of Ti inCo2Zr, CoZr2 and CoZr3 is about 10.7 at.% Ti,1.9 at.% Ti and 4.3 at.% Ti, and that of Zr in TiCo3, TiCo2(h), TiCo2(c), TiCo and Ti2Co is about 0.9 at.% Zr, 8.4 at.% Zr, 6.0 at.% Zr, 7.5 at.% Zr and 16.0 at.% Zr, respectively. Two ternary phases are observed.