Applications of laser ultrasonic technique on nondestructive testing and evaluation of materials

Nondestructive testing (NDT) is a wide group of analysis techniques used in science and industry to evaluate the properties of a material, component or system without causing damage. As one of unconventional NDT technology, laser ultrasonic technique (LUT) have played an important role in inspecting the materials in some extreme environments, such as high temperature, high pressure, corrosion, radioactive and etc. LUT uses lasers to generate and detect ultrasonic waves in a noncontact way. Thus, compared with the traditional ultrasonic technique, LUT has the advantages of high precision, high sensitivity without requirement for geometry of target material. So far, LUT has been well applied to composite inspections for the aerospace industry and on-line hot tube thickness measurements for the metallurgical industry. This talk describes the application of LUT on flaws detection in rail and thermal barrier coatings.