Additive Manufacturing: Advanced Characterization for Industrial Applications: On-Demand Oral Presentations
Sponsored by: TMS Advanced Characterization, Testing, and Simulation Committee, TMS Additive Manufacturing Bridge Committee
Program Organizers: Nadia Kouraytem, Utah State University; Fan Zhang, National Institute of Standards and Technology; Lianyi Chen, University of Wisconsin-Madison
Friday 8:00 AM
October 22, 2021
Room: On-Demand Room 1
Location: MS&T On Demand
Invited
Operando Synchrotron X-ray Studies of Metal Additive Manufacturing: From Fundamentals to Industrial Applications: Tao Sun1; 1University of Virginia
In recent decade, additive manufacturing (AM) technologies have transitioned from rapid prototyping tools to effective manufacturing approaches for producing end-use commercial components in the medical, aerospace, automobile, energy industries, among many others. Despite the early success of metal AM in industry, there are still substantial R&D efforts in academia and government labs on tackling the most fundamental issues. In particularly, synchrotron facilities provide multi-dimensional characterizations that examine the dynamic evolution of materials structures with dimensional and the temporal resolutions key to metal AM processes. Integrating the unique capabilities of synchrotron x-ray techniques and sophisticated operando systems are enabling the industry to improve numerical models, interrogate critical materials problems, particularly those associated with processing under far-from-equilibrium conditions, as well as prediction and management of defects and rare events. Here, I will present a brief overview of the industrial applications of operando synchrotron x-ray techniques at the Advanced Photon Source.
Thermo-mechanical Behavior of AM and Wrought IN718 Under High-strain-rate Tensile Deformation: Owen Kingstedt1; John Varga2; S-Danial Salehi1; 1University of Utah; 2Sandia National Laboratory
In this study, the conversion of plastic work to heat, also known as the Taylor-Quinney coefficient (β), of Inconel 718 (IN718) is investigated. Three material conditions are examined, specifically wrought IN718, additively manufactured (AM) IN718 in the as-built condition, and AM IN718 that has been recrystallized through a solutionizing heat treatment. Adiabatic deformation is achieved using a tension split-Hopkinson pressure bar. During deformation IR thermography measurements are captured to assess β as a function of strain. Electron backscatter diffraction was utilized to measure grain size, morphology, and texture. It was observed that wrought IN718 had the lowest conversion of plastic work to heat (β = 0.2). The as-built as-built IN718 had an intermediate conversion (β = 0.3), and the recrystallized condition had the greatest conversion efficiency (β = 0.45). The observed magnitudes of β are discussed in light of the microstructural similarities and differences of each material condition.
Predicting Failure Location in Additively Manufactured Metals Using an Improved Void Descriptor Function: Dillon Watring1; Jake Benzing2; Orion Kafka2; Newell Moser2; Li-Anne Liew2; John Erickson3; Nikolas Hrabe2; Ashley Spear1; 1University of Utah; 2National Institute of Standards and Technology; 3Sandia National Laboratories
Metal additive manufacturing (AM) has become a vital tool in many industries. However, large variations in pore distributions (size, shape, and location) are a major concern in structural applications given certain porosity populations can cause premature failure in metal components. Parametric studies show that the variations in porosity depend on AM processing parameters. A previously derived pore metric called the void descriptor function was shown to improve the predictive capabilities of fracture location by accounting for pore location, size (assuming spherical shape), and distance to free surface. This work expands upon the original void descriptor function to generalize and enhance the representation of pore networks by fitting ellipsoids around 3D pores and by weighting pore location based on neighbors of interest, which more accurately represents pore clustering. This improved and computationally efficient function is shown to enable accurate prediction of fracture location in mesoscale additively manufactured Inconel 718 tensile specimens.
In-situ Characterization of Pore Formation Dynamics in Pulsed Wave Laser Powder Bed Fusion: Seyed Mohammad Hojjatzadeh1; Qilin Guo1; Niranjan Parab2; Minglei Qu1; Luis Escano1; Kamel Fezzaa2; Wes Everhart3; Lianyi Chen1; 1University of Wisconsin-Madison; 2Argonne National Laboratory; 3Department of Energy’s Kansas City National Security Campus Managed by Honeywell FM&T
Laser powder bed fusion (LPBF) is an additive manufacturing technology with the capability of printing complex metal parts directly from digital models. Between two available emission modes employed in LPBF printing systems, pulsed wave (PW) emission provides more control over the heat input compared to continuous wave (CW) emission. However, parts printed with pulsed wave LPBF (PW-LPBF) commonly contain pores, which degrades their mechanical properties. Here, we reveal pore formation mechanisms during PW-LPBF in real time by using in situ high-speed synchrotron x-ray imaging technique. We found the vapor depression collapse proceeds when the laser irradiation stops within one pulse, resulting in occasional pore formation during PW-LPBF. We also revealed that the rapid melt pool solidification during pulsed-wave laser melting resulted in cavity formation and subsequent formation of pore pattern in the melted track. The pore formation dynamics revealed in this study can provide guidance on developing pore elimination approaches.