Cell structure development during cyclic deformation of near-[001] and near-[011] copper single crystals

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2024-11, Vol.916, p.147357, Article 147357
• Main Authors: Wang, Bohan, Shi, Haomeng, Miyazawa, Tomotaka, Ohtsuka, Masahiro, Muto, Shunsuke, Arai, Shigeo, Fujii, Toshiyuki
• Format: Article
• Language: English
• Subjects: Cell structure; Copper single crystal; Dislocation; Fatigue; Multiple slip
• ISSN: 0921-5093
• DOI: 10.1016/j.msea.2024.147357

Dislocation cell structures significantly influence the fatigue failure process. Research on the cell structures in multiple-slip-oriented copper single crystals has focused primarily on the [1‾11] orientation, whereas formation mechanisms and development processes of cell structures in [001] and [011] copper single crystals remain unclear. Therefore, this study examines the dislocation structures of near-[001] and near-[011] copper single crystals under cyclic deformation at high strain amplitudes. The cyclic stress–strain curve of the [011] crystals showed a distinct plateau at plastic shear strain amplitudes ≤7.5 × 10−3. In the plateau region, the dislocation structures consisted of cell structures along the (111) primary slip plane and matrix wall structures. Furthermore, (111) cell structures were formed in the single-slip deformation bands (DBs). After the plateau region, several types of new DBs could be observed due to the activation of multiple-slip systems. Multiple-slip DBs have a higher degree of plastic strain concentration than single-slip DBs, leading to the preferential formation of cell structures. For the near-[001] crystals, (111) cell structures were uniformly formed throughout the matrix, without the formation of DBs. The formation mechanism of the (111) cell boundary was independent of the stress axis and resulted from the interaction between the primary and coplanar slip systems. •Cell structures in [001] and [011] copper single crystals were characterized.•First analysis of fatigue behavior in [011] crystals after plateau region.•Formation mechanism of the (111) cell boundary is independent of the stress axis.•Multiple-slip deformation bands bear higher strain than those of single-slip.•Activated slip systems and formation sites mutually influence cell formation.