Using Laser Ultrasound to Detect Subsurface Defects in Metal Laser Powder Bed Fusion Components.

Laser powder bed fusion offers many advantages over conventional manufacturing methods, such as the integration of multiple parts that can result in significant weight-savings. The increased design freedom that layer-wise manufacture allows has also been seen to enhance component performance at little or no added cost. For such benefits to be realized, however, the material quality must first be assured.

Laser generation of Lamb waves for defect detection: experimental methods and finite element modeling.

The propagation of Lamb waves generated by a pulsed laser beam in an aluminum sheet is modeled using finite element analysis, and the interaction with defects is studied and compared to experimental results. The ultrasonic Lamb waves are detected by an electromagnetic acoustic transducer (EMAT). The frequency content of the received wave is shown to be enhanced when the generation point is situated directly over the defect in both the modeled and experimental cases.