Plastic effects during sheet metal forming can lead to undesirable distortions in formed components. Here, the three-stage work hardening and plastic strain recovery ("springback") in a cold-rolled, α-phase commercially pure titanium is examined. Interrupted standard tensile tests with in situ x-ray diffraction and quasi-in situ electron backscatter diffraction show that twinning plays a minor role in both of these phenomena. The experiments give evidence that the observed work hardening plateau is the result of an abrupt activation and multiplication of 〈c+a〉 slip and a subsequent redistribution of load between grain families. The springback can be attributed to inelastic backwards motion and annihilation of dislocations, driven by backstresses from dislocation-based hardening during loading. The peak broadening behavior, observed by x-ray diffraction, suggests that the internal stress state is highest in the rolling direction, resulting in consistently higher springback magnitude along this direction.
- work hardening plateau
- in situ X-ray diriffraction
Sofinowski, K., Šmíd, M., Van Petegem, S., Rahimi, S., Connolley, T., & Van Swygenhoven, H. (2019). In situ characterization of work hardening and springback in grade 2 α-titanium under tensile load. Acta Materialia, 181, 87-98. https://doi.org/10.1016/j.actamat.2019.09.039