Torsion fatigue endurance and load ratio confrontation R=0 VS. R=-1 on the AISI 6061-T6 aluminum alloy.

Torsion Fatigue test were carried out on the aluminum alloy 6061-T6 for two load ratios: R=-1 and R=0, both of them at 10Hz of frequency, room temperature and without control of environmental humidity. Results reveal a noticeable fatigue endurance reduction on tests with R=0 against tests at R=-1. Load ratio was fixed by changing only the start angle of testing. In this paper is also showed the torsion fatigue machine developed by the authors; that is capable of commissioning torsion tests at different frequencies and load ratios, such machine is under patent consideration to the Mexican Institute of Industrial Property. Fatigue life and fracture surfaces at macro and micro scale were analyzed for both torsion fatigue load ratios and finally, corresponding conclusions were enlisted