It was recalled that the addition of a small amount of impurity could significantly affect the irradiation-induced microstructures of metals and simple alloys. This had been attributed to solid-solution effects, such as point defect trapping at impurity atoms, and to precipitation. The present study was intended to clarify the manner in which impurity trapping affected point defect clustering rates and defect-cluster growth rates. A rate theory model was modified so as to include point defect trapping processes at solute atoms. The effect of cascade vacancy cluster formation was first investigated by assuming various configurations for the clusters. It was found that cascade vacancy clusters tended to disappear via vacancy emission, before relaxing into thermally stable configurations such as stacking fault tetrahedra. By using the calibrated cascade cluster model, point defect evolution under a wide range of solute-trapping conditions was calculated.

Y.Katoh, A.Kohyama: Nuclear Instruments and Methods in Physics Research B, 1995, 102[1-4], 12-8