New samples with artificial voids for ultrasonic investigation of material damage due to creep

This paper describes the application of acoustic birefringence measurement for evaluation of material degradation due to creep. The problem with ultrasonic investigation of the influence of creep-induced voids on ultrasonic wave velocities is the lack of samples containing well-defined voids. The only way to “produce” damaged material with numerous voids is accelerated creep laboratory test or long-term service of material in high temperature and stress. To describe voids it is necessary to perform laborious metallographic examination of damaged material. Paper presents glass samples with artificial semi-flat voids created with laser engraving technique. Results of ultrasonic wave velocities and acoustic birefringence measurements in glass samples proved that laser engraving can be helpful for the experimental investigation of voids influence on solid acoustic properties.