Strain-based fatigue data for Ti–6Al–4V ELI under fully-reversed and mean strain loads

This article presents the experimental data supporting the study to obtain the mean strain/stress effects on the fatigue behavior of Ti–6Al–4V ELI. A series of strain-controlled fatigue experiments on Ti–6Al–4V ELI were performed at four strain ratios (−1, −0.5, 0, and 0.5). Two types of data are included for each specimen. These are the hysteresis stress–strain responses for the cycle in a log10 increment, and the maximum and minimum stress–strain responses for each cycle. Fatigue lives are also reported for all the experiments.


a b s t r a c t
This article presents the experimental data supporting the study to obtain the mean strain/stress effects on the fatigue behavior of Ti-6Al-4V ELI. A series of strain-controlled fatigue experiments on Ti-6Al-4V ELI were performed at four strain ratios (À 1, À 0.5, 0, and 0.5). Two types of data are included for each specimen. These are the hysteresis stress-strain responses for the cycle in a log 10

Value of the data
The experimental data presented in this article can be used to provide basis for the cyclic deformation and fatigue behavior of Ti-6Al-4V ELI, a widely used material in biomedical and aerospace applications, under zero and non-zero mean strain/stress conditions.
Most of the generated data on fatigue behavior of Ti-6Al-4V are related to high-cycle fatigue with the use of a stress-life approach. However, the presented data were collected using the strain-life approach, which has been proven to correlate low-cycle fatigue data in a better manner than stress-life [2]. The data in this article can be used to improve current fatigue models and elucidate the material's behavior under strain-controlled cyclic loadings in presence of mean stresses.
The presented data can be used as a benchmark for fatigue research of Ti-6Al-4V ELI under more complex cyclic loads.

Data
The data included in this paper were obtained from the strain-controlled fatigue tests on Ti-6Al-4V ELI. Mean strain/stress effects were studied by performing fatigue experiments at different strain ratios, R ε , and various strain amplitudes, ε a . For each specimen, two types of data, the hysteresis stress-strain responses and the peak (maximum)/valley (minimum) stress-strain responses, are available. The hysteresis stress-strain responses were collected in a log 10 increment, while the peak/ valley stress-strain responses were recorded at each cycle. The corresponding fatigue lives are also

Experimental design, materials and methods
Fatigue specimens were machined from Ti-6Al-4V ELI Grade 5 round bar with 12.7 mm diameter to create round-shaped specimens with a reduced uniform gage section. The geometry and dimensions of the specimens, as illustrated in Fig. 1, were designed to comply with ASTM standard E606/ E606M À 12 [1]. Fatigue tests were performed at four strain ratios, including R ε ¼ À1 (fully-reversed), R ε ¼ À0.5 (tension-compression), R ε ¼ 0 (tension-release), and R ε ¼0.5 (tension-tension). For each strain amplitude, a minimum of two fatigue experiments were conducted to ensure that the test data was consistent. The strain amplitudes, ε a , ranged from 0.0015 to 0.012 mm/mm depending on the applied R ε . All tests were conducted at room temperature with an average 41% relative humidity, and using a servohydraulic test machine with a sinusoidal waveform input. The test frequency was adjusted for each strain amplitude to eliminate any temperature and strain rate effects on the cyclic behavior. Experiments that reached over 10 6 cycles were determined to be a run-out and no duplicate test was performed. For some long life tests in the fully elastic region where the cyclic stress response was constant, the control mode was switched to load-control and the test frequency was increased to reduce the testing time. Table 1 summarizes the compiled data information for all strain-controlled fatigue tests, which were organized by the strain ratio, R ε , and the strain amplitude, ε a .