Fatigue Failure Behavior of TC17 Titanium Alloy in 3.5% NaCl Solution

Abstract:

To study the fatigue failure behavior of TC17 titanium alloy in salty-water environment, ultrasonic fatigue tests of TC17 titanium alloy in different medias were conducted and the fatigue properties and failure characteristics were analyzed. The fatigue tests of TC17 titanium alloy in air and 3.5% NaCl solution were carried out using ultrasonic fatigue test system, and the fatigue lives in different medias under the same stress amplitude were compared and analyzed. The conversion model of fatigue life in two kinds of media in the "finite life" stage was put forward, and the stress intensity factors were calculated according to Murakami model and micro-gully model. The fracture characteristics of fatigue test specimens were observed by SEM, and the effects of 3.5% NaCl solution on fatigue failure characteristics were compared and analyzed. Results show that in 3.5% NaCl solution environment, the calculated results of stress intensity factor with surface micro-gully as the main variable are more consistent with the actual failure behavior, and due to the influence of corrosion environment, there are some phenomena such as "accumulation" of matrix materials and multiple crack sources on the fracture surface.