The effect of Ti-6Al-4V microstructure on the performance of ultrasonic soft tissue cutting tips

Mill annealed Ti-6Al-4V is a commonly used material in high-power ultrasonic devices, including cutting tips for ultrasonic soft tissue surgical devices. The advantages of Ti-6Al-4V include its high elastic strain limit, low acoustic attenuation, and biocompatibility. It is known that the microstructure of Ti-6Al-4V can influence its mechanical and acoustic properties. This research focuses on how altering the Ti-6Al-4V microstructure affects the performance of ultrasonic surgical tips. Through heat treatment five distinct types of Ti-6Al-4V sample were created: mill annealed; course lamellar; widmanstatten; fully equiaxed alpha plus intergranular beta; bimodal - equiaxed plus lamellar. The mechanical and acoustic properties of the samples and their dynamic response to ultrasonic excitation were characterised. Acoustic attenuation of the samples in static state was measured using a time of flight experiment. Strong links were shown between microstructural features and material properties, with the fully l...