Chemical analysis of precipitates in metallic alloys using coincidence Doppler broadening of positron annihilation radiation

Two-detector coincidence Doppler broadening (CDB) method of positron annihi lation radiation is applied to the study of precipitates in metals. As the first step, the CDB spectra for many kinds of elements are measured to obta in the "fingerprint" of each element for the chemical analysis of the preci pitates in metals. Utilizing the fingerprint of Cu, we made chemical analys is of nano-particles formed in the initial stage of thermal aging in a FeCu alloy, and found that the particles are consisting of Cu only and free fro m vacancies, which demonstrates the usefulness of this method in the study of the precipitates. (C) 2000 Elsevier Science Ltd. All rights reserved.