ATOM ATOM COLLISION CASCADES IN NONUNIFORMLY STRESSED METALS

Atom-atom collision cascade development in alpha-Fe under different non-uniform stress fields is studied by a computer simulation method. It is shown that such fields can significantly change a cascade region structure. The depleted zone becomes more compact; the distance between it and that where interstitials are stopped increases; the number of stable defects produced is less than that in an unloaded crystal. These effects can be caused by changes in the atom-atom replacement chain development in the low-energy cascade branches and threshold displacement energy. Special investigations of the variations in the displacement threshold energy E(d) under non-uniform stresses have been carried out. It is shown that averaged in all directions the E(d) change is near to 9%. The present results are compared with cascade development and E(d) calculations in alpha-Fe under a uniform load.