Data for: Ultrasonic characterization of material heterogeneities in stainless steel parts fabricated by powder bed fusion
Description
These are the raw ultrasonic waveform files and nanoindentation measurements for three additively manufactured 316L stainless steel components with different fabrication parameters. Each part's length is divided into four segmented regions where their fabrication energy densities change. Part V+ begins at 33 J/mm^3 and increases in energy density by 3 J/mm^3 with each segment. Part C remains at a constant 33 J/mm^3 throughout the part. Part V- begins at 33 J/mm^3 and decreases in energy density by 3 J/mm^3 with each segment. We have found that the ultrasonic waves in regions with higher energy densities will traverse more quickly, as shown by the shorter time of flight, and vice versa. Similarly, nanoindentation measurements of reduced modulus and hardness follow this trend. We have measured the direction in which the parts were fabricated (build direction) and the segmented regions that are perpendicular to the build direction (transverse directions). The build direction longitudinal wave velocity measurements are considerably lower than their transverse direction counterparts, indicating anisotropy between the two directions. In Part C, we have removed material from one of its surfaces and recorded its ultrasonic and nanoindentation measurements with each material removal iteration. Changes in the material properties are more prominent by nanoindentation, suggesting material heterogeneity between the part's surface and interior. The README.txt file has information on how to navigate the files and process the data.
Files
Steps to reproduce
Apply pulse-echo ultrasound by square wave pulser-receiver to any of the 18 faces (top and bottom surfaces and 4 segments per side). Process the raw waveform data using peak-to-peak or similar signal processing methods. For nanoindentation, mechanical polishing of the surfaces was done using 600, 800, and 1200 U.S. industrial grit emery paper and cooled with cooling water during polishing. The parts were placed on the Hystiron nanoindenter stage, and indentation locations were located in regions of level surfaces with few to no scratches by the built-in optical microscope.