PRECIPITATION IN THE 15-5 PH ALLOY BY ANOMALOUS SMALL-ANGLE X-RAY-SCATTERING

The precipitation of A type partially coherent precipitates occurring in the first step of the structural hardening of the 15-5 PH martensit ic stainless alloy was studied by anomalous small angle X ray scatteri ng at four absorption edges (KCr, KFe, KNi and KCu). An important anom alous effect was clearly observed at the KFe and KCu absorption edges. The precipitation occurs according to the two-phase model. Considerin g our alloy as a pseudo-ternary one (Cr+Ni, Fe, Cu), it has been possi ble to determine the slope of the tie-line corresponding to the precip itation taking place at 500-degrees-C.