Ultrasonic characterization of material heterogeneities in stainless steel components produced by laser powder bed fusion
We introduce pulse-echo ultrasound as a method for characterizing the impact of powder bed fusion parameters on the properties of additively manufactured stainless-steel components, their material anisotropy, and location-dependent heterogeneity. Our results indicate that accurate characterization r...
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Elsevier
2025-07-01
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| Series: | Next Materials |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2949822825001327 |
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| author | Kenneth Walton Mikhail Skliar |
| author_facet | Kenneth Walton Mikhail Skliar |
| author_sort | Kenneth Walton |
| collection | DOAJ |
| description | We introduce pulse-echo ultrasound as a method for characterizing the impact of powder bed fusion parameters on the properties of additively manufactured stainless-steel components, their material anisotropy, and location-dependent heterogeneity. Our results indicate that accurate characterization requires careful selection of ultrasonic propagation paths, which must consider the direction of additive layering, variations in processing parameters, and the component's geometry. We employed two distinct methods to estimate material properties from ultrasonic data: One assumes isotropy, while the other accounts for anisotropic interactions during the propagation of elastic waves. When applied to samples fabricated with laser energy densities ranging from 24 to 42 J/mm³ , these methods revealed transverse isotropy and weak anisotropy (quantified by small Thomsen parameters, ε=0.0651 and γ=0.0092) and less than a ∼6 % change in acoustic impedance. The assumption of isotropy, in this case, leads to small errors (less than 4 % or 1 % for Young's modulus in the build or transverse directions) when estimating orthotropic material properties using ultrasonic data measured along just two orthogonal directions, one of which must align with the build direction. By comparing ultrasonic measurements — which aggregate the spatial variability in material properties along the length of elastic wave propagation into a single value — with localized measurements obtained from surface nanoindentation, we uncovered and spatially profiled significant differences between the surface and interior properties. Specifically, the surface Young's modulus decreased from approximately 210 GPa to 180 GPa within a depth of about 3 mm. We attribute this surface-localized heterogeneity in PBF-fabricated components to distinct thermal histories experienced by the surface and interior regions. Collectively, the results of this study establish a framework for the ultrasonic characterization of material heterogeneity and anisotropy in material properties and demonstrate its application in additively manufactured metal components. |
| format | Article |
| id | doaj-art-b668356715bf4248a43b8474b2b0152d |
| institution | DOAJ |
| issn | 2949-8228 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Elsevier |
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| series | Next Materials |
| spelling | doaj-art-b668356715bf4248a43b8474b2b0152d2025-08-20T03:08:06ZengElsevierNext Materials2949-82282025-07-01810061410.1016/j.nxmate.2025.100614Ultrasonic characterization of material heterogeneities in stainless steel components produced by laser powder bed fusionKenneth Walton0Mikhail Skliar1Department of Chemical Engineering, University of Utah, 50 S Central Campus Dr., Salt Lake City, UT, United StatesCorresponding author.; Department of Chemical Engineering, University of Utah, 50 S Central Campus Dr., Salt Lake City, UT, United StatesWe introduce pulse-echo ultrasound as a method for characterizing the impact of powder bed fusion parameters on the properties of additively manufactured stainless-steel components, their material anisotropy, and location-dependent heterogeneity. Our results indicate that accurate characterization requires careful selection of ultrasonic propagation paths, which must consider the direction of additive layering, variations in processing parameters, and the component's geometry. We employed two distinct methods to estimate material properties from ultrasonic data: One assumes isotropy, while the other accounts for anisotropic interactions during the propagation of elastic waves. When applied to samples fabricated with laser energy densities ranging from 24 to 42 J/mm³ , these methods revealed transverse isotropy and weak anisotropy (quantified by small Thomsen parameters, ε=0.0651 and γ=0.0092) and less than a ∼6 % change in acoustic impedance. The assumption of isotropy, in this case, leads to small errors (less than 4 % or 1 % for Young's modulus in the build or transverse directions) when estimating orthotropic material properties using ultrasonic data measured along just two orthogonal directions, one of which must align with the build direction. By comparing ultrasonic measurements — which aggregate the spatial variability in material properties along the length of elastic wave propagation into a single value — with localized measurements obtained from surface nanoindentation, we uncovered and spatially profiled significant differences between the surface and interior properties. Specifically, the surface Young's modulus decreased from approximately 210 GPa to 180 GPa within a depth of about 3 mm. We attribute this surface-localized heterogeneity in PBF-fabricated components to distinct thermal histories experienced by the surface and interior regions. Collectively, the results of this study establish a framework for the ultrasonic characterization of material heterogeneity and anisotropy in material properties and demonstrate its application in additively manufactured metal components.http://www.sciencedirect.com/science/article/pii/S2949822825001327Pulse-echo ultrasoundSurface nanoindentationLaser powder bed fusionMaterial characterizationAnisotropy and material heterogeneity |
| spellingShingle | Kenneth Walton Mikhail Skliar Ultrasonic characterization of material heterogeneities in stainless steel components produced by laser powder bed fusion Next Materials Pulse-echo ultrasound Surface nanoindentation Laser powder bed fusion Material characterization Anisotropy and material heterogeneity |
| title | Ultrasonic characterization of material heterogeneities in stainless steel components produced by laser powder bed fusion |
| title_full | Ultrasonic characterization of material heterogeneities in stainless steel components produced by laser powder bed fusion |
| title_fullStr | Ultrasonic characterization of material heterogeneities in stainless steel components produced by laser powder bed fusion |
| title_full_unstemmed | Ultrasonic characterization of material heterogeneities in stainless steel components produced by laser powder bed fusion |
| title_short | Ultrasonic characterization of material heterogeneities in stainless steel components produced by laser powder bed fusion |
| title_sort | ultrasonic characterization of material heterogeneities in stainless steel components produced by laser powder bed fusion |
| topic | Pulse-echo ultrasound Surface nanoindentation Laser powder bed fusion Material characterization Anisotropy and material heterogeneity |
| url | http://www.sciencedirect.com/science/article/pii/S2949822825001327 |
| work_keys_str_mv | AT kennethwalton ultrasoniccharacterizationofmaterialheterogeneitiesinstainlesssteelcomponentsproducedbylaserpowderbedfusion AT mikhailskliar ultrasoniccharacterizationofmaterialheterogeneitiesinstainlesssteelcomponentsproducedbylaserpowderbedfusion |