The application of holographic interferometry in the nondestructive testing of materials

The application of holographic interferometry in nondestructive testing is due to a very exact measurement of surface deformations. It is shown that the visibility of faults and thus the success of this technique essentially depend on the way such an object surface is deformed. Five methods, dielectric heating, static bending load, heat treatment, local impact, and a modified impact method using a liquid layer are used for three technical parts, a clutch disk, a turbine blade, and a thick-walled steel plate. The results show the importance of a correct load.