Laser ultrasonic testing of titanium alloy parts inside the directed energy deposition additive manufacturing chamber (Conference Presentation)

Additive manufacturing (AM) requires a new paradigm for quality assurance testing. A nondestructive test setup has been integrated into an AM chamber. A pulsed laser generates Rayleigh waves that are then received by a laser interferometer. Two levels of interrogation are investigated; detection of defects using linear ultrasonic methods and tracking changes in microstructure using nonlinear ultrasonic methods. One of the challenges in AM chambers is surface roughness, which affects both light collection for reception as well as the Rayleigh wave propagation characteristics. This paper describes the laser ultrasonic system, its integration into an AM chamber, and some sample results.