Quenching of dilute Be [sbnd]H alloys: A TEM study

Abstract

Be is a relevant material in nuclear and reactor technology. It has recently gained additional prominence as a coating material for Tokamak fusion devices. In this latter context, the reactions of Be with the hydrogen isotopes are very important. Recently, rather precise hydrogen solubility measurements both in {alpha}-Be and in {beta}-Be became available. This paper presents an adapted form the solubility of H in Be in the {alpha}-phase. The solubility in terms of the atom ratio H/M can be expressed by: S = 1.723 {times} 10{sup {minus}4} sq. root p exp({minus}16700/RT) (H){sub (M)} where p is the pressure in MPa, T the temperature and R the gas constant. Thus, {alpha}-Be is an endothermic occluder of hydrogen. Another endothermic occluder of H is, for instance, Cu where TEM techniques showed the quenching of dilute Cu-H alloys from high temperatures leads to the formation of hydrogen bubbles around room temperature. Matter is ejected from the growing bubble by prismatic dislocation loop punching. In other TEM studies, it was established that quenching of the exothermic occluder of hydrogen, Mg, does not lead to bubble precipitation but to the formation of small hydride particles.