LAUSR

The interdiffusion process in a three-component alloy system has been studied by means of numerical analysis. The composition profiles for a ternary system were generated making use of the closed-form solution with a constant interdiffusion matrix with the accompanying analysis of the diffusion paths. Two methods [the Fitting Method and the modified square root diffusivity (MSQRD) method] have been considered to investigate the inverse interdiffusion problem for application to a single interdiffusion couple measurement. The Fitting Method simultaneously fits the required functional form into the data obtained for two composition profiles. Such fitted parameters are used to determine the constant interdiffusion matrix. The MSQRD method has been applied to the generated composition profiles and performs very well for all the cases considered. It was found that the errors of the MSQRD method are, in general, lower than in the use of the Fitting Method even without imposing artificial noise on the composition profiles to mimic the experimental data. In addition, it has been shown that the back-tests of the composition profiles must not be used as the only proof of the reliability of the methods used.