The effective bias of tangled dislocations

It is demonstrated that dislocations in tangles (defined as regions containing a higher than average dislocation density) may be considered to have an effective bias which is less than their intrinsic bias and which can become less than the bias of the surrounding network dislocations. The effect is found for circumstances where the intrinsic bias is either independent of, or increases with, the local dislocation density. The analysis allows previous conclusion of Wolfer et al. (1972, 1974) (that tangled dislocations can be relatively neutral sinks for irradiation-produced point defects) to be extended to embrace circumstances excluded from their previous considerations. (author)