2023 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2023): Wire-fed DED: Materials and Experiments
Program Organizers: Joseph Beaman, University of Texas at Austin
Wednesday 8:00 AM
August 16, 2023
Room: Salon A
Location: Hilton Austin
Session Chair: Carolyn Seepersad, Georgia Tech
8:00 AM
Challenges in Wire-Arc Additive Manufacture of Nickel Aluminum Bronze: Bradley Jared1; Tiffany Quigley1; Joshua Penney1; Devon Goodspeed1; Steven Williams1; Matthew Roach1; William Hamel1; Jakub Preis2; Somayeh Pasebani2; 1University Of Tennessee, Knoxville; 2Oregon State University
Nickel aluminum bronze (NAB) is a complex alloy commonly selected for marine applications due to it cavitation strength and bio-fouling resistance. Historically a cast alloy, recent work has explored wire-arc additive manufacturing (WAAM) of NAB for large scale metal structures using cold metal transfer (CMT) welding. Process development started by exploring parameters informed by literature descriptions of welding and standard metal inert gas (MIG) deposition. Such MIG parameters proved inadequate as process development was performed to establish stable deposition parameters using CMT. Critical process parameters will be discussed such as interpass temperature, heat input, contact to workpiece distance and shielding gas coverage. Progress in printing complex part geometries, resulting material microstructures and tensile properties will also be presented. Finally, future research needs for WAAM of NAB will be highlighted.
8:20 AM
Failure Mechanisms in Grading Inconel 625-GRCop 42 via Hybrid Wire-powder Directed Energy Deposition: Somayeh Pasebani1; Kuba Preis1; Sriram Manoharan1; Brian Paul1; Donghua Xu1; 1Oregon State University
Multi-metal additive manufacturing requires the joining of dissimilar metals yielding joints that are prone to increased residual stress and the precipitation of brittle intermetallic phases. Compositionally graded alloys (CGAs) are materials in which two alloys are joined via transition layers with compositions selected to help avoid brittle phases and minimize residual stress. Although CGAs have been demonstrated across multiple material systems, a holistic design strategy for CGAs has yet to proposed. In this work, two CGAs are designed from Inconel 625 to GRCop42 and from Inconel 625 to a nickel-aluminum-bronze alloy by use of CALculation of PHAse Diagrams (CALPHAD) and a derived dissimilar metal residual stress coefficient. The CGAs are printed via a hybrid wire-powder directed energy deposition process. Failure mechanisms are discussed, and the ability to minimize brittle phases and residual stress is demonstrated.
8:40 AM
Framework Development for Optimization of DED Parameters using Nickel-Aluminum Bronze Feedstock and Arc Wire Directed Energy Deposition: Jack Canaday1; Jennifer Semple1; Matthew Dantin1; Charles Fisher1; 1Nswc Carderock Division
Selection of appropriate process parameters for directed energy deposition (DED) is critical to build success but presently requires a prohibitive quantity of time, capital, and experience. To reduce decision-making risk, a framework is proposed to support statistical optimization using an experimentally derived process model. The developed framework was demonstrated using nickel-aluminum-bronze (NAB) feedstock with the arc wire DED process pursuing application requirements of as-built surface condition and global productivity for thin-wall geometry. Quantitative analytical metrics were devised apply structured light metrology and thermal simulation for each trial condition to establish the process model. The obtained process model was used to select an optimized set of process parameters which enabled fabrication of a thin-wall component geometry in an optimized condition. The described framework is intended to be tailorable based on process, material, and application requirements through selection of process inputs, defined analytical criteria, and experimental geometry investigated.
9:00 AM
Process-integrated Alloy Adjustment in Laser Deposition Welding with Two Wires: Laura Budde1; Nick Schwarz1; Jörg Hermsdorf1; Stefan Kaierle1; Ludger Overmeyer1; 1Laser Zentrum Hannover e.V.
For DED with wire as filler material, the material selection is mostly limited to commercially available welding wires. This limits the achievable material properties for cladding and Additive Manufacturing purposes. Using a coaxial deposition welding head, in which two different wires can be fed and controlled individually, the alloy composition can be adjusted in the common process zone in-situ.In this study, the two wire materials X2CrNiMo19-12 and G4Si1 are used in different mixing ratios to fabricate single weld seams. The different mixing ratios are achieved by varying the wire feed rates. The material content in the weld is varied between 0% and 100% in 20% steps. The weld seams are examined with regard to the distribution of alloying elements, hardness and microstructure. Homogeneous mixing of the two materials was achieved at all mixing ratios. The hardness depends on the mixing ratio and varies between 170HV0.1 and 428 HV0.1.
9:20 AM Cancelled
Process Development for the Wire Arc Additive Manufacturing of AlSi10Mg: Moritz Baldauf1; Tobias Hauser1; Kamalesh Bharadwaj1; Philipp Lohrer1; Lucas Jauer2; Johannes Henrich Schleifenbaum2; 1BMW Group; 2RWTH Aachen
Wire Arc Additive Manufacturing (WAAM) is an additive manufacturing process based on robotic arc welding that enables the flexible, tool-less production of large-scale metal components. WAAM of aluminum alloys is particularly challenging due to their low melting temperature and high thermal conductivity, which result in a small process window. In this work, the processing of the cast alloy AlSi10Mg (EN AW-4046) by WAAM was investigated. For this purpose, a basic parameter development for WAAM of Al 4046 was carried out. Consecutively, first simple thin-walled geometries were built and analyzed regarding their mechanical properties, porosity, and surface properties. By adjusting the parameters, correlations between weld settings, path planning and the resulting properties have been identified. Furthermore, it was observed that the process tends to be sensitive to wire quality, which can be compensated by increasing the energy input.
9:40 AM Break
10:10 AM
On Process Stability In WAAM-CMT of Aluminum Alloys: Austen Thien1; Kathryn Kelly1; Caroline Massey1; Christopher Saldana1; 1Georgia Institute of Technology
Wire-arc additive manufacturing (WAAM) has become a cost-efficient metal additive manufacturing process. However, depositing aluminum with WAAM is challenging due to its sensitivity to heat input (linear energy density), which can cause undesirable surface topology waviness if not controlled. Thus, a process window is needed that can produce stable geometry and deposition conditions while minimizing production times. In this study, 5183 aluminum alloy wire is used to deposit 10-layer walls with varying wire feed speeds (WFS) and traverse speeds (TS) (at a constant WFS/TS ratio) and varying interlayer temperature (IPT). In-situ process data consisting of optical contact-tip-workpiece-distance (CTWD) and current/voltage measurements are collected to determine process condition stability throughout the build. Part geometry is measured using a 3D scanner and build porosity is characterized via digital X-ray. A process window is identified that produces stable surface topology and process conditions at a minimal production time.
10:30 AM
Simulation of Anisotropic Mechanical Behavior of Additively Manufactured Ti-6Al-4V Wall Structures using VPSC: Rajib Halder1; Anthony Rollett1; Jake Benzing2; 1Carnegie Mellon University; 2National Institute of Standards and Technology
This work explores the effect of processing parameters on texture development in Ti-6Al-4V wall components fabricated by wire-feed Directed Energy Deposition process, one of the additive manufacturing techniques. Microstructure and texture were characterized using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). An open-source software package, MTEX, was used to perform grain reconstruction, orientation analysis, variants selection analysis, and generate IPF maps. A strong variation in texture was observed along the build direction in laser hot wire deposited single walls. A viscoplastic self-consistent (VPSC) model was used to simulate the deformation response under uniaxial tension applied along vertical, horizontal, and diagonal directions with respect to the build direction of the single wall component. An excellent fitting was achieved between the simulated and experimental stress-strain curves. VPSC simulation successfully captured the tension-compression asymmetry and the anisotropic response of Ti-6Al-4V single walls.
10:50 AM
Solidification Behavior, Texture Evolution, and Mechanical Behavior of Large Scale Fusion Additively Manufactured Steels: Interplay Between Chemistry and Unique Processing Conditions: Saket Thapliyal1; Patxi Fernandez-Zelaia1; Yousub Lee1; Andrzej Nycz1; Sarah Graham1; Andres Rossy1; Michael Kirka1; 1Oak Ridge National Laboratory
The multiphysics in DED wire-arc additive manufacturing (WAAM) process can differ significantly from other powder-based fusion additive manufacturing processes. This engenders the need for investigating the chemistry-processing-structure-properties relationships for DED WAAM processed alloys. In this work, we investigate the effect of interplay between multiple physical phenomena on process thermokinetics, solidification behavior, solute segregation behavior, microstructural evolution and ensuing mechanical behavior of the DED WAAM processed stainless steels. Insights on factors determining a single crystal-like texture in DED WAAM processed austenitic steels are provided. The implications of spatially-varying thermokinetics for undercooling, solute segregation and phase transformation behavior in steels are also discussed. Furthermore, we discuss the effects of hierarchical deformation mechanisms in moderate stacking fault energy steels on room and high temperature mechanical behavior. This work is expected to improve the understanding of chemistry-processing-structure-properties relationships in DED WAAM processed stainless steels, and thus facilitate microstructure design of steels with DED WAAM.
11:10 AM
Wire Arc Additive Manufacturing in Steel Foundries: Eric Weflen1; Matthew Frank1; Frank Peters1; 1Iowa State University
This work presents the system design of a robotic hybrid additive and subtractive manufacturing system for steel foundries to reduce supply chain disruptions caused by a skilled labor shortage and harsh working conditions. Automation promises to ease the labor shortage but falls short in environments with high variation and ambiguous decision-making. These challenges were overcome by leveraging human adaptability and uncertainty in decision-making, paired with automation conducting repetitive tasks in harsh environments. Documenting the existing process revealed the current welding approach for removing and refilling metalcasting production anomalies. Tasks were divided into those suited for automation and those best suited for a human operator. The operator continues to identify and remove anomalies while sensing and robotics automate weld preparation by machining, refilling using Wire Arc Additive Manufacturing (WAAM), and surface blending by grinding. This research serves as a case study for integrating hybrid manufacturing into production environments.
11:30 AM
Additive Manufacturing of ODS Steels using Powder Feedstock Atomized with Elemental Yttrium: Seongun Yang1; Donghua Xu1; Dongqing Yan1; Marc Albert2; Somayeh Pasebani1; 1Oregon State University; 2Electric Power Research Institute
This study investigates the microstructure and mechanical properties of an austenitic ODS steel produced by the Laser Directed Energy Deposition (LDED) process using powder feedstock atomized with elemental yttrium. The Microstructure of the samples was characterized by electron microscopy, and mechanical properties were measured using a tensile test and nanoindentation. Further, the thermal stability of the LDED-produced ODS steels were evaluated. As-printed samples showed a cellular structure with Si-Mn-Y-O-enriched nanoparticles that were found to be amorphous. After 100 hrs at 1000°C in an argon atmosphere, a partially recrystallized microstructure with a decrease in the number density of Y-O-enriched nanoparticles with crystalline structure was revealed. The as-printed (600 W, 600 mm/min) samples exhibited an ultimate tensile strength of 774 MPa and an elongation at a break of 22%. A lower ultimate tensile strength of 592 MPa and higher elongation of 42% was measured after 100 hrs at 1000°C.