Point Defects in Metals in Thermal Equilibrium

Abstract

A brief critical review is given of the status of the experimental determination of the equilibrium concentration of point defects in metals. It is argued that the question whether, in addition to vacancies, self-interstitials contribute significantly must be considered open and that accurate simultaneous measurements of the macroscopic and microscopic (unit-cell) thermal expansion might help in answering it. For high-accuracy determination of the differential thermal expansion at high temperatures (melting points of Cu, Ag, Au and above) a laser-interferometry-neutron diffraction experiment is being built up at the Institute Laue-Langevin. Preliminary experiments on Cu are reported, indicating that the desired accuracy may be achieved.