Recrystallization of cold rolled oxide dispersion strengthened copper during room temperature annealing

Abstract

Static discontinuous recrystallization was studied during room temperature annealing of a newly designed 80% room temperature rolled oxide dispersion strengthened copper. At early stages of annealing, fine new oriented nanosized/submicron grains were recrystallized in the unique matrix of single brassoriented deformed grain. Upon longer annealing time up to 14 months, the size, area fraction and number density of the recrystallized grains increased significantly along with changing the crystallographic textures. The analysis of misorientation angle distribution of boundaries indicated transformation of low angle boundaries to high angle boundaries results in nucleation of recrystallized grains by significant contribution of static recovery. Furthermore, the constant level of mechanical hardness after recrystallization was interpreted by the balance between grain size hardening, oxide particle hardening and strain hardening.

Microstructure development in cryogenically rolled oxide dispersion strengthened copper

“…Then, increasing the rolling reductions results in increasing the number fraction of LABs to number fractions of 57% and 43% in 40%Re and 60%Re, respectively. This promotion of LABs is interpreted by development of deformationinduced boundaries during cryogenic rolling [20] and is in contrast to little change of LABs during room temperature rolling of ODS copper [1]. The black HABs can be seen as partially elongated in the direction of rolling and their fraction decrease with promoting of the fraction of substructures inside the grains.…”

“…Recently, the annealing of cold rolled ODS copper has been confirmed as a result of recovery process during long time storage at room temperature [20]. In other side, observation of severly deformed area in high resolution presents two important microstructural features; as shown in Fig.…”

“…The evaluation of crystallographic texture during rolling of fcc metals especially copper alloys has performed widely in literature and is an effective instrument to study the microstructural development [1,4,9,10,15]. In Fig.…”

“…A thorough literature survey shows that one unusual behavior of cryogenic deformed copper is recrystallization or in some case grain growth at room temperature [9][10][11][12][13]. It is hypothesized that the microstructural instabilities are attributed to a high density of vacancies in the cryodeformed material, giving rise to the exceptionally high grain-boundary mobility [14].…”

Statistical Approach for Understanding the Effect of Specimen Size on the Yield Stress and Its Scattering in Mechanically-Alloyed Cu and ODS-Cu Obtained by Micro-Pillar Compression Test

“…where G is shear modulus (44.7 GPa for Cu),¯is the Poisson ratio (0.34 for Cu), M is the Taylor factor (3.0), 28) b is the magnitude of the Burgers vector (2.56 © 10 ¹10 m). 29) r 0 is the inner cut-off radius of a dislocation core, which assumed to be the same magnitude of Burgers vector.…”