DISCONTINUOUS PRECIPITATION IN THE COPPER-INDIUM SYSTEM FROM THE VIEWPOINT OF NUCLEAR IN-111 PROBES IN GRAIN-BOUNDARIES

We employ the discontinuous precipitation occurring in a supersaturate d solid solution of indium in copper in order to prove that In-111 nuc lear probes are successfully placed in deeply buried grain boundaries by means of low-temperature diffusion. The observation of perturbed an gular correlations of gamma rays in the decay of In-111 to Cd-111 yiel ds the signal of the intermetallic delta phase (Cu7In3) as a clear man ifestation of the phase transformation. Experiments with either diffus ed or implanted samples allow us to distinguish and characterize diffe rent stages of the precipitation process.