Fundamental factors on formation mechanism of dislocation arrangements in cyclically deformed fcc single crystals

Abstract

This paper systematically summarizes the cyclic deformation behaviors of different kinds of face-centered cubic (fcc) single crystals, including copper, nickel, silver, as well as copper–aluminium, copper–zinc alloys in attempt to provide a historical perspective of the developments over the last several decades. Combined with plenty of previous research results, the influencing factors on cyclic deformation behaviors can be listed as follows: orientations, stacking fault energy (SFE), short-range order (SRO) and friction stress, or more generally, the ease of cross slip. Among them, the effect of orientations mainly reflects in the formation of the complex dislocation patterns, which depends on the activating secondary slip system. According to the effect of slip mode, the materials can be divided into two types: pure metals and alloys. For pure fcc metals, the effect of SFE is decisive. Due to the easy cross slip of screw dislocations, regular dislocation arrangements, e.g. veins, persistent slip bands (PSBs), labyrinth and cell patterns, are always to form. With increase in alloying element, antiphase boundary energy gradually replaces SFE to become a new decisive factor affecting the cyclic deformation behaviors of fcc alloy single crystals. The corresponding dislocation arrangements consist of dipole array and stacking faults (SFs) under the influence of planar slip. The relationship among several factors is well explained, which will help us better understand the nature of the fatigue damage of metallic materials and then improve the performance of the related materials.