Grain refinement and its microstructure in repetitive roll bending and straightening of copper sheets
Abstract
The commercial thin sheet has a low plasticity and anisotropy in mechanical properties due to the hardening phenomenon in the roll forming process. Using the rolled thin sheet, the manufacturing of the micro-size parts is easy to cause poor formability and poor forming quality. A repetitive roll-bending and straightening (RRBS) method suitable for micro-size materials is proposed, and RRBS based severe plastic deformation and recrystallization annealing of pure copper sheets are investigated experimentally for improving its micro forming formability. With the increase of the pass number of RRBS, the work hardening phenomenon is serious, and the hardness of the material increases. At the same time, the inhomogeneity factor (IF) value decreases as the number of RRBS passes increases, which improves deformation uniformity of the material. The grain size of the sample deformed by the 20 RRBS passes and annealed at 400 °C for 60 min is approximately 17 μm. The investigation in this paper provides a guideline for a potential grain refining process of the rolled thin sheets/foils metal as a blank directly used for micro-forming.
- Publication:
-
Materials Research Express
- Pub Date:
- July 2019
- DOI:
- 10.1088/2053-1591/ab1625
- Bibcode:
- 2019MRE.....6g6540Z
- Keywords:
-
- pure copper thin sheets;
- repetitive roll-bending and straightening (RRBS);
- grain refinement;
- recrystallization annealing