A STUDY OF LOW TEMPERATURE DECOMPOSITION OF A PB-SN SOLID SOLUTION SUPERSATURATED IN TIN BY X-RAY DIFFUSION

The decomposition at low temperature, -47°C, of the Pb-Sn solid solution oversaturated (23% tin), has been studied by several methodes of X-ray diffusion. Two stages in the tin precipitation have been put in evidence: the first one corresponds to a progressive polygonisation of the matrix accompanied by a sudden diminution of the tin concentration; the tin clusters have a spherical shape (the radii are of approximately 70 Å) and they are incoherent with the matrix. The second stage corresponds to a coalescence of spherical clusters into laminar precipitates. © 1969.