Methods of testing the material of a metal object made by additive manufacturing. An electromagnetic acoustic transducer (EMAT) is used to transmit long duration acoustic signals into the object, and to receive response signals representing resonance of acoustic waves within the material. At least one resonance peak is identified and used to determine attenuation and/or wave velocity. These values can then be used to determine material properties, such as porosity, Shear Modulus, Young's Modulus, or Poisson's Ratio.
Adam C. Cobb; Albert J. Parvin, Jr.; Barron J. Bichon