Ultrasonic Nondestructive Testing and Evaluation Method of Special Processing Mechanical Properties

Based on the acoustic microscopy nondestructive testing system, the surface acoustic wave velocities of two types of special samples that were processed by additive manufacturing (3D printing) and powder metallurgy were measured by using line-focusing PVDF transducers, which can be used for the inversion of mechanical properties of materials. The surface wave velocities at different positions and angles were obtained by defocus measurement and time-resolved method. Mechanical properties at the corresponding position and angle were calculated by these surface wave velocities. To improve the resolution of the transducer, the line-focusing PVDF transducer with 1 mm wide film was developed specially to reduce the detection area. Measurement results show that the surface wave velocities in the arbitrary directions are constant for powder metallurgical material, namely isotropy. Surface wave velocities of 3D printing material at different directions are slightly different, showing anisotropy. The acoustic performance of arbitrary angle or small area of materials can be measured by the acoustic microscopic nondestructive measurement system, which is used to inverse the material mechanical properties with high precision and reliability. It provides a nondestructive testing and evaluation method for performance test of new materials and the assessment of new processing.