PHASE-EQUILIBRIA IN THE NI-CR-TI SYSTEM AT 850-DEGREES-C

The isothermal cross-section through the ternary phase diagram Ni-Cr-T i at 850 degrees C was constructed by means of diffusion couples and e quilibrated alloys. No ternary phases exist in the system at this temp erature. The topology of the isotherm is largely determined by the pre sence of the TiCr2-Laves phases which are in equilibrium with the bina ry Ti-Ni intermetallics. About 10 at.% of Ni can be dissolved in the h exagonal P-TiCr2 at 850 degrees C, and the solubility of nickel in cub ic alpha-TiCr2 is approximately 4 at.%. A small amount of nickel or ch romium increases the stability of the b.c.c. beta-Ti structure. At thi s temperature the beta-Ti(Ni)-based solid solution can dissolve up to 18 at.% of Cr. (C) 1998 Elsevier Science S.A.