Laser-induced surface acoustic wave spectroscopy (LiSAWS) allows quick and non-destructive access to elastic properties of coatings, surfaces and surface-near bulk materials. Furthermore, the mechanical weakening due to cracks, pores and delamination can be evaluated, as they influence the propagation of surface waves as well. Therefore, the method is established as a quick and powerful tool for surface characterization and established today in research and development, quality control and as a precise and scientific reference method. After successful application of the method to semiconductor materials and thin coatings from PVD, ALD, and other deposition techniques in the thickness range of few micrometers, recent works showed that using different sensors the depth of information can be extended to at least 500 µm. That allows measurement of thicker coatings and surface properties of freestanding build up structures made by laser cladding, powder bed processes, thermal spraying, and others.

In this work, precise measurement of the effective Young's modulus was used to determine the influence of process parameters such as temperature distribution and build-up direction, as well as material properties such as residual porosity on various examples (laser cladding WC-Co/316L, electron beam melted TiAl alloy, thermally sprayed Al2O3 insulation coating). Furthermore, it is shown whether the effective modulus is related to the tensile strength and the number of cycles in fatigue tests of a 𝛽-Ti-42Nb alloy prepared by laser powder bed fusion at different build-up directions and residual porosities. With regard to the practical implementation of the measurement, the advantages compared to other methods for measuring the Young’s modulus of additively manufactured components, like indentation or tensile test, are emphasized. Furthermore, technical possibilities and limitations with regard to the in-situ use for layer-by-layer characterization in powder bed processes are discussed.