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Effects of PANDA LPBF-3D Printing Parameters on Metal Parts Surface Wettability

Faculty Member: Amir Ali

In laser powder bed fusion (LPBF) additive manufacturing (AM) processes, layers of powder are raked or rolled on a build plate and selectively melted using energy from a laser beam. The process can create metal parts with intricate geometries that are difficult, if not impossible, to make using conventional subtractive and formative manufacturing techniques. It is employed in the aerospace and defense industries, given its ability to reduce the buy-to-fly ratio from 1:20 to 1:5 and shrink lead times from months to days. The LPBF process has recently been proposed for making advanced nuclear reactor parts, including fabricating nuclear fuel and other major components, such as reactor cores and vessels. The critical impetus in using LPBF for nuclear applications is its ability to produce complex geometries, resulting in highly efficient heat exchangers, reduce weight, cost, and component fabrication time, and take advantage of novel materials that are difficult to machine, cast, or forge. Remarkably, several challenges that induce multi-scale flaw formation must be overcome, resulting in significant variations in part properties. Some flaws include surface inhomogeneous microstructure (variation in grain size, anomalous phase distribution, and micro-segregation), porosity, cracking and distortion, residual stress, poor surface roughness, and geometric flaws. These defects directly impact the component’s thermophysical and mechanical components, which may lead to component or system failure when exposed to extreme environmental conditions in the reactor core. Therefore, understanding the effects of LPBF printing parameters, such as laser beam power and scanning speed, on the formation of surface defects is crucial. In this primary project, the surface defects will be quantified and related to these parameters through simple measurements, including surface energy and wettability (contact angle and surface roughness), with the support of Scanning Electron Microscopy (SEM) surface imaging to enable the interpretation of the results.

Student Research Experience: Working in collaboration with staff members at the Idaho National Laboratory and Boise State University, the students will participate in three key areas of this research: (1) Additive manufacturing, learning about the process from sample design and optimization, and down-selection of appropriate printing parameters; (2) Surface Characterization; using state-of-the-art tools, including Goniometer (contact angle), surface profilometer (roughness), and use of SEM imaging; and (3) perform data analysis and drive the potential relationship between surface flaws formation and their corresponding wettability measurements and printing parameters for fine-tuning and optimize the fabrication process.