Surface topography investigations on nickel alloy 625 fabricated via laser powder bed fusion
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Laser powder bed fusion as an additive manufacturing process produces complex surface topography at multiple scales through rapid heating, melting, directional cooling, and solidification that are often governed by laser path and layer-to-layer scanning strategies and influenced by process parameters such as power, scan velocity, hatch distance, and resultant energy density. Investigations on manufactured surfaces, as-built and after applying electropolishing, are performed using stylus profilometry, digital optical microscopy, and scanning electron microscopy techniques to reveal the complex surface texture of the nickel alloy 625 test cubes that are produced by following an experimental design. Surface texture is further explored using image processing together with machine learning-based algorithms. Measurement uncertainty is also discussed briefly. The results reveal a complex nature of laser powder bed fusion created surface topography and textures as exposed with electropolishing that may further lead to a quantitative understanding of such textures and their formations influenced by different scanning strategies and process parameters.
KeywordsPowder bed fusion Surface topography Surface texture Nickel alloy
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Certain commercial equipment, instruments, or materials are identified in this paper in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose.
The support by the NIST under the financial assistance number 70NANB14H227 and assistances are gratefully acknowledged.
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