Method for Determining Composition Profiles and Diffusion-Generated Substructure in Small Diffusion Zones

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Abstract
An x‐ray diffraction technique is described which may be used to determine the composition profile of small diffusion zones as well as the diffusion‐generated substructure. Thus far, this technique is restricted to volume diffusion and has been applied in the case of a single‐phase solid solution; however, the methods may be readily applied to volume diffusion in multiphase systems. Data are presented for a system containing an 8‐μ deposit of Ni on a [111] oriented single crystal of Cu. This composite was diffused at 900 °C for 45 min, 2 h, and 5 h. A Matano‐Boltzmann analysis of the composition profile gave good agreement with recently obtained diffusion coefficients. The degree of diffusion‐generated subgrain misorientation increased with annealing time and zone size up to the maximum time for our experiments. There was no evidence for the existence of nonuniform strain, and the distribution of subgrain misorientation was found to be Gaussian. Also, the widths of the Gaussian misorientation functions appear to be proportional to the lattice‐parameter gradient, although this relationship is not exact.