Theoretical treatment of creep cavity growth with application to embrittlement by inert gas

The principal theoretical models proposed to explain the creep fracture of unirradiated metals and alloys are reviewed. A scheme is presented which allows for the mixed sequential/independent relationships between growth mechanisms. The models are applied to the problem of the high temperature embrittlement induced in the austenitic alloys by the helium generated during irradiation. It is shown that cavity growth is likely to be controlled by the limiting rate of vacancy generation on grain boundaries or by geometrically necessary dislocation creep constraint. (author)