Ternary diffusion and thermodynamic interaction in the β solid solutions of Ti-Al-Zr alloys at 1473 K

The purposes of the present study are as follows: (a) to determine, using the Matano-Kirkaldy method, the binary and ternary interdiffusion coefficients in the β solid solutions of the ternary Ti-Al-Zr alloys at 1473 K and the impurity diffusion coefficients of Zr in Ti-Al alloys at 1473 K, and (b) to estimate the thermodynamic interactions between solute and solute atoms in β Ti-Al-Zr solid solutions at 1473 K. In the β Ti-Al-Zr alloys, the main interdiffusion coefficients ( and ) and the cross interdiffusion coefficients, ( and ) have positive values. The values of are larger than those of . In the Ti-Al-X( = V, Cr, Fe, Co, Zr ) alloys, the values of main coefficients are < < < < < at 1473 K. The repulsive interactions exist between Al and X ( = V, Cr, Fe, Co, Zr ) atoms in the Ti-Al-X alloys, because the ratio values of cross coefficients to main one are positive in sign. On the other hand, the interactions between Ti (solvent) and X ( = V, Cr, Fe, Co, Zr ) atoms are attractive in the present alloys, since the ratio of converted interdiffusion coefficients in the ternary alloys show negative values.