The precipitation kinetics of the alloy, when quenched within the miscibility gap and annealed isothermally at 900K, were studied by using positron annihilation lifetime and Doppler broadening techniques. The size of the Pt-rich precipitates was deduced from small-angle neutron scattering measurements. The results of the positron annihilation measurements were explained by assuming that a fraction of the positrons, depending upon the morphology of the material, was trapped at misfit dislocations on the boundaries of Pt-rich precipitates. The positron trapping rate per unit area of the interphase boundary was estimated by combining positron annihilation data with small-angle neutron scattering data. The importance of this parameter, and of positron lifetime data, in characterizing the local structure of the interphase boundary was emphasized.

W.Pahl, V.Gröger, G.Krexner, A.Dupasquier: Journal of Physics - Condensed Matter, 1995, 7[29], 5939-47