The 13th World Conference on Titanium 2015: Stability of Residual Stresses in Ti-6Al-4V Components due to Mechanical Loads

Residual stresses are an important factor for the design of components that require high fatigue life and low weight while keeping demanding safety requirements.
This work describes the stability of residual stresses due to cyclic mechanical loads. The residual stress relaxation can be described by local plastic deformation. In order to determine the plastification behaviour of Ti-6Al-4V, Low-Cycle-Fatigue (LCF) tests were performed on specimens.
The yield stress defines the beginning of the plastification and can vary due to cyclic hardening and softening effects. To describe these effects, a material model was applied and parameterized using the LCF data. With this material model, a simulation model was developed to calculate the residual stress relaxation.
Additionally, cyclic tests were performed on machined specimens. The residual stresses of the specimens were measured by x-ray diffraction before and after testing. The measured residual stress relaxation was matched by the simulation.