Determination of the Elastic Properties at Aging of Medical Ti-6Al-4V ELI Alloy by Ultrasonic Velocity Measurements

摘要

In this paper, we report the experimental data of the elastic properties of the Young's modulus and shear modulus based on the variation in the ultrasonic velocity parameter during the microstructural evolution in a Ti-6Al-4V alloy with two-bimodal and Widmanstaetten-varying microstructures. The two different initial microstructures were treated thermally by aging at 515, 545, and 575°C at different times from 1 min to 576 h to induce a precipitation process. Ultrasonic measurements of shear and longitudinal wave velocities, scanning electron microscopy image processing, optical microscopy, and microhardness measurements were performed, establishing a direct correlation with the measurements of the ultrasonic velocity and the elastic properties developed during the thermal treatment by artificial aging. The results of the ultrasonic velocity show a very clear trend as the aging time progresses, which is affected by precipitation of Ti_3Al particles inside the α phase. In this way, we can find, in a fast and efficient way, the elastic properties developed during the heat treatment by long-term aging, since the presence of these precipitates hardens the material microstructure, thus affecting the final mechanical properties.