Ternary interdiffusion in L12–Ni3Al with ternary alloying additions of Ir and Ta was investigated at 1473K using solid/solid diffusion couples. Average ternary interdiffusion coefficients were determined from an integration of the interdiffusion fluxes calculated directly from experimental concentration profiles. The magnitudes of the DNiNi and DAlAl coefficients (table 1)were determined to be much larger than those of the DIrIr and DTaTa coefficients (table 2). Iridium which substituted on Ni-sites significantly influenced the interdiffusion of Ni, and the DNiIrAl coefficients were determined to be large and positive (table 3). On the other hand, Ta substituting for Al influenced the interdiffusion of Al significantly, and the DAlTiNi coefficients were determined to be large and positive. Excellent agreement was found with ternary interdiffusion coefficients determined by Boltzmann–Matano analysis. Profiles of concentrations and interdiffusion fluxes were also examined in order to estimate the binary interdiffusion coefficients in Ni3Al, and tracer diffusion coefficients of Ir (14.7 x 10−16m2/s) and Ta (2.6 x 10−16m2/s) in Ni3Al.Effects of Ir or Ta Alloying Addition on Interdiffusion of L12–Ni3Al. N.Garimella, M.Ode, M.Ikeda, H.Murakami, Y.H.Sohn: Intermetallics, 2008, 16[9], 1095-103

Table 1

DNiNi and DAlAl Interdiffusion Coefficients in Ni-Al-Ir Alloys at 1473K