Non-Contact Acousto-Thermal Signatures in as Received and Fatigue Damaged Ti-6Al-4V (Postprint).

摘要

Interaction of high amplitude acoustic waves with materials produces a small increase in the temperature that can be detected and measured using an IR camera. The changes in temperature as a function of time, due to interaction of high amplitude 20 kHz acoustics, with as received and fatigue damaged polycrystalline Ti-6Al-4V samples are compared. The maximum temperature reached by the sample has been found to increase with increasing fatigue cycles. The role of multiple physical mechanisms, responsible for conversion acoustic energy to heat, like the sample geometry (finite dimension), the microstructure (grain size), and dislocation density are examined. The theoretically evaluated temperature changes are observed to be in reasonable agreement with experimental measurements. The significance of the details of microstructure and dislocation properties needed in theoretical evaluation of temperature changes are used to explain the observed differences between experimental measurements and theoretical calculations.