Low-cycle fatigue tests between 573 and 873K were carried out with a total strain range of 1% in order to study the cyclic behaviour and dislocation structure developed in Zircaloy-4. According to them, three ranges of temperature were distinguished: low, intermediate and high. The intermediate one was characterized by the activation of a dynamic strain aging process which was manifested mechanically by an incremental rate of cyclic hardening and microstructurally by a pronounced increase in the dislocation density. In order to analyse the dislocation dynamics on the evolution of the microstructure, interrupted tests were performed. These results were used to propose a model of dislocation glide and accumulation for a hexagonal metal.

Influence of Dynamic Strain Aging on the Dislocation Structure Developed in Zircaloy-4 during Low-Cycle Fatigue. I.Alvarez-Armas, S.Hereñú: Journal of Nuclear Materials, 2004, 334[2-3], 180-8