Crack growth in titanium alloy under ultrasonic loading

Abstract

The ultrasonic loading is usually associated with a very high cycle fatigue problem of crack initiation. It has been shown many times by Shanyavskiy (2014), Nicholas (1999) and others that such high frequency loading may to cause’unexpected’ in-service fatigue failures of turbo-jet elements, such as compressor disks and blades. Many different studies were carried out on the problem of crack initiation in different structural materials, Bathias and Paris (2004), Mayer (2013), even for titanium alloys McEvily et al. (2008), Nikitin et al. (2016). Nonetheless the problem of early fatigue crack growth under ultrasonic loading reminded outside of main scientific interests. In the resent years the interest to this subject is increasing Perez-Mora et al. (2015), Stanzl-Tschegg et al. (2016). This paper is focused on the problem of early crack growth in two-phases titanium alloy under ultrasonic loading. The first results of crack growth tests on VT3-1 (close to Ti-6Al-4V) titanium alloy and mathematical model for prediction of crack front evolution are presented. The results of mathematical modeling are comparing with a shape of fatigue crack at the fracture pattern for curvilinear crack front.