Article Article
Real-Time Characterization of Laser-Generated Melt Pools using Ultrasound

In this article, ultrasound is used to monitor the real-time evolution of laser-generated melt pools created on the surface of a stainless steel plate. A plurality of spherically focused immersion transducers was used to measure various shear scattering amplitudes from the generated melt pool as it evolves with increasing laser duration. The scattering of ultrasound out of the plane of incidence is found to be particularly sensitive to melt pool depth. A finite element model that incorporates both conductive thermal transport and elastodynamic wave propagation is used to help confirm the existence of scattering from the melt pool and the temperature field around it. Lastly, the scattered response is found to exhibit a temporal evolution that follows the temperature evolution in the plate. This work represents a step forward in the development of a real-time ultrasonic technique to (1) qualify additively manufactured parts, and (2) characterize melt pools created during additive manufacturing processes.


Clark, D., S.D. Sharples, and D.C. Wright, 2011, “Development of Online Inspection for Additive Manufacturing Products,” Insight - Non-Destructive Testing and Condition Monitoring, Vol. 53, No. 11, pp. 610–613. 

DebRoy, T., H.L. Wei, J.S. Zuback, T. Mukherjee, J.W. Elmer, J.O. Milewski, A.M. Beese, A. Wilson-Heid, A. De, and W. Zhang, 2018, “Additive Manufacturing of Metallic Components - Process, Structure, and Properties,” Progress in Materials Science, Vol. 92, pp. 112–224.

Everton, Sarah K., Matthias Hirsch, Petros Stravroulakis, Richard K. Leach, and Adam T. Clare, 2016, “Review of In-situ Process Monitoring and In-situ Metrology for Metal Additive Manufacturing, Materials & Design, Vol. 95, pp. 431–445.

Gubernatis, J.E., E. Domany, and J.A. Krumhansl, 1977, “Formal Aspects of the Theory of the Scattering of Ultrasound by Flaws in Elastic Materials,” Journal of Applied Physics, Vol. 48, No. 7, pp. 2804–2811.

Karloff, A.C., A.M. Chertov, and R.Gr. Maev, 2009, “Enhancing Real-Time Ultrasound Signatures of Molten Nugget Growth for Quality Evaluation of Resistance Spot Welds,” 2009 IEEE International Ultrasonics Symposium, Rome, Italy.

Kocimski, J., W. Arthur, P. Kustron, A.M. Chertov, R. Gr. Maev, M. Korzeniowski, and A. Ambroziak, 2009, “Modelling Ultrasonic Wave Prop-agation in a Multilayered Medium for Resistance Spot Welding,” 2009 IEEE International Ultrasonics Symposium, Rome, Italy.

Lesthaeghe, T.J., R.A. Adebisi, S. Sathish, M.R. Cherry, and P.A. Shade,2017, “Toward Characterization of Single Crystal Elastic Properties in Polycrystalline Materials using Resonant Ultrasound Spectroscopy,” Materials Evaluation, Vol. 75, No. 7, pp. 930–940.

Lew, A., J.E. Marsden, M. Ortiz, and M. West, 2003, “Asynchronous Varia-tional Integrators,”Archive for Rational Mechanics and Analysis, Vol. 167, No. 2, pp. 85–146.

Reider, H., A. Dillhöfer, M. Spies, J. Bamberg, and T. Hess, 2014, “Online Monitoring of Additive Manufacturing Processes using Ultrasound,” 11th European Conference on Non-Desructive Testing, Prague, Czech Republic.

Reider, H., M. Spies, J. Bamberg, and B. Henkel, 2015, “On- and Offline Ultrasonic Characterization of Components Built by SLM Additive Manu-facturing,” AIP Conference Proceedings, 42nd Annual Review of Progress in Quantitative Nondestructive Evaluation, Minneapolis, Minnesota, doi: 10.1063/1.4940605.

Schmerr, L.W. Jr., 2016, Fundamentals of Ultrasonic Nondestructive Evalua-tion: A Modeling Approach, 2nd edition, Springer, Berlin, Germany.

Wohlers, 2017, Wohlers Report 2017, Wohlers Associates, Fort Collins, CO.

Usage Shares
Total Views
248 Page Views
Total Shares
0 Tweets
0 PDF Downloads
0 Facebook Shares
Total Usage