Early-Stage Recrystallized Grains in Copper Single Crystals Deformed in Tension along <111> Direction

Abstract

The objective of the present study was to characterize early-stage recrystallization in copper single crystals. Two crystals with different front surfaces, i.e., {110} or {112}, were deformed in tension along the <111> direction to a tensile strain of 0.2. The deformation was uniform without deformation bands. Thin disk specimens prepared from the deformed <111>{110} and <111>{112} crystals were heated in a high vacuum to a set temperature with a holding time of 10 s, and subsequently observed. This process was repeated by raising the heating temperature for each step until the first detection of recrystallized grains. In all specimens, recrystallization was found after annealing at almost the same temperature, about half of the melting point in the absolute temperature scale. Each recrystallization aggregate was composed of a pair of major recrystallized grains with a coherent twin boundary. Small annealing twins were detected inside the larger recrystallized grains but not in the smaller grains. The present results suggest that recrystallization in copper begins with the formation of pairs of twin-related recrystallized grains, followed by the introduction of annealing twins.

Fig. 4 (a) SEM/EBSD inverse-pole-figure orientation map of a pair of major recrystallized grains (RG1 and RG2) in the annealed <111>{110} specimen. (b) The 111 pole figure of RG1 and RG2. The common 111 pole is represented by a red circle.