Ultrasonic testing is a type of nondestructive testing (NDT) method that uses high-frequency sound waves to detect and evaluate defects in materials. The test is performed by applying a high-frequency sound wave to the material using an ultrasonic transducer.

The transducer converts the electrical signals that generate the sound wave into mechanical vibrations, which are transmitted into the material. Any defects in the material, such as cracks, voids, or inclusions, will cause changes in the propagation of the sound wave, which can be detected and evaluated using specialized equipment. Ultrasonic testing is commonly used to inspect metals, ceramics, and composites for defects that could affect the strength and performance of the material.