Experimental studies of helium in metals

Abstract

A short review is given of recent experimental studies of helium in metals, emphasizing fundamental He behavior at low temperatures (room temperature and below), low He concentrations (∼1 at.% He) and in the absence of radiation induced defects. Some of the main points are: (a) interstitial He is generally locally mobile at room temperature and below, (b) impurities behave as strong unsaturable traps which lose their identity with increasing numbers of trapped He atoms, and (c) the eventual microstructure of He charged metals appears qualitatively the same in pure undamaged materials as in radiation-damaged materials.