Additive Manufacturing of Large-scale Metallic Components: Aluminum and Titanium Alloys/In-situ Monitoring
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Additive Manufacturing Committee
Program Organizers: Sougata Roy, Iowa State University; Sneha Prabha Narra, Carnegie Mellon University; Andrzej Nycz, Oak Ridge National Laboratory; Yousub Lee, Oak Ridge National Laboratory; Chantal Sudbrack, National Energy Technology Laboratory; Albert To, University of Pittsburgh; Yashwanth Bandari, AddiTec Technologies LLC
Wednesday 8:30 AM
March 22, 2023
Room: 25A
Location: SDCC
Session Chair: Albert To, University of Pittsburgh
8:30 AM
Augmenting Operando Neutron Diffraction Measurement of WAAM with Multispectral Thermal Imaging: James Haley1; Kyle Saleeby1; Clay Leach1; Christopher Fancher1; Thomas Feldhausen1; Guru Madireddy1; Yousub Lee1; An Ke1; Alex Plotkowski1; 1Oak Ridge National Laboratory
Live lattice strain evolution from complex thermal fields and phase transformations is now observable due to development of an operando neutron diffraction WAAM experimental platform (OpeN-AM). The penetrating power of neutrons enables measurement of weld pools and geometries relevant to large scale metal manufacturing. To complement the time-resolved point probe capability of the neutron source, a suite of multispectral infrared and visible cameras were deployed to spatially resolve temperature, emissivity, and distortion of the deposited component. IR spectral filtering methods were employed to correct for the natural variation in surface conditions encountered in WAAM. Topics of discussion include extensibility of methods to production AM, uncertainty quantification, applications in model validation, and the potential for dynamically targeted neutron sampling.
8:50 AM
Understanding Stress Evloution in Wire Arc Additive Manufacturing of LTT Alloy Using Finite Element Methods: Guru Charan Reddy Madireddy1; Yousub Lee1; Kyle Saleeby1; James Haley1; Christopher Fancher1; Ke An1; Wei Tang1; Thomas Feldhausen1; Alex Plotkowski1; 1Oak Ridge National Laboratory
The residual stresses in large-scale additive components manufactured by wire-arc additive manufacturing (WAAM) are dependent on various factors such as geometry, tool path, interlayer temperatures, process conditions, and material. In this work, a part was printed on a wire-arc based additive system (Tormach) using low temperature transformation (LTT) alloy, which induces compressive stress through martensite phase transformation. The phase transformations and temperatures during the printing process were observed using operando neutron diffraction and IR cameras. Finite element modeling was employed to integrate the thermo-mechanical additive manufacturing process with phase transformations models, Johnson-Mehl-Avrami-Kolmogorov (JMAK) for diffusional transformation and Koistien-Marburger (KM) diffusionless transformation. Transformation induced plasticity was considered to incorporate the stresses from phase transformations along with thermal stresses. The model enables a deeper understanding of stress evolution mechanisms during WAAM and was validated against the temperatures and lattice strains measured using operando neutron diffraction and IR data.
9:10 AM
High Deposition Rate Wire Arc Additive Manufacturing of “Unweldable” Precipitation Hardened Aluminum Alloys: Joe Kleindienst1; Alex Yearsley1; Nick Bagshaw2; Jeff Lints2; Jeremy Iten3; Xun Liu4; Dennis Harwig4; Zhenzhen Yu1; Jonah Klemm-Toole1; 1Colorado School of Mines; 2Fortius Metals; 3Elementum 3D; 4The Ohio State University
High deposition rate additive manufacturing such as gas metal arc-based wire arc additive manufacturing (WAAM) is ideally suited to produce large and highly complex shapes. The inherent requirement for low density materials in ground transportation and aerospace applications necessitates high strength aluminum alloys. However, high strength Al alloys in the 2XXX, 6XXX, and 7XXX alloys are considered “unweldable” with arc welding methods. In this presentation, we show that controlling the solidification conditions during WAAM by introducing nucleation sites can eliminate solidification cracking and enable large scale WAAM of precipitation hardened Al alloys for high strength and lightweight components. We discuss processing – microstructure – mechanical property relationships in these WAAM materials and possibilities for mechanical property improvement with heat treatment.
9:30 AM Invited
Ultrasonic Effects on Gas Tungsten Arc Based Wire Additive Manufacturing of Aluminum Nanocomposite: Xun Liu1; Tianzhao Wang1; 1Ohio State University
This study focuses on a newly developed ultrasonically assisted (UA) gas tungsten arc based wire additive manufacturing (GTA-WAAM) process, where the ultrasonic probe is directly dipped into the local molten pool and travels behind the arc during deposition. UA-WAAM of AA7075 metal matrix nanocomposite with TiB2 nanoparticles is performed. Interacting mechanisms of deposition parameters, ultrasonic amplitude and GTAW hot-wire system are comprehensively analyzed. Overall, UA shows the capabilities of reducing porosity, restraining the formation of the inferior interlayer structures, delaying precipitates over-aging, and enhancing dispersion of nanoparticles. These improved microstructure features directly enhance mechanical properties of the UA-WAAM samples, as shown in the hardness and tensile test results. UA benefits are more significant at a lower travel speed, which allows longer UA-melt interaction time. Lastly, UA amplitude needs to be balanced to avoid severe agitation of molten pool for the most optimized results.
10:00 AM Break
10:20 AM Invited
In-Situ Monitoring and Control for Large-Scale Metal AM: Romilene Cruz1; Jeffrey Riemann1; 1Formalloy
Metal Additive Manufacturing processes such as Directed Energy Deposition (DED) provide a scalable method to produce complex geometries with incredible benefits for applications, but there are challenges between concept design and producing a part, particularly as the size increases. In order to create high-quality, repeatable parts, in-process monitoring can be utilized to both collect data and control the build process. With Directed Energy Deposition, various monitoring and control modes are available to reduce parameter development times, improve build quality, and limit operator input during a build. These control modes include melt pool, powder flow, laser power, and geometric monitoring and control. These control modes not only significantly reduce the process parameter development cycle, but also result in a higher quality build to include density and material properties.
10:50 AM
Rapid Process Qualification for W-DED Ti-6Al-4V: Jonathan Pegues1; Brian Hoover2; Timothy Ruggles1; Luis Jauregui1; Shaun Whetten1; Andrew Kustas1; 1Sandia National Laboratories; 2Advanced Optical Technologies, Inc.
Wire based directed energy deposition (W-DED) witness sampling and characterization is fundamentally more challenging than many additive manufacturing methods. There are several process-structure challenges associated with W-DED materials that can affect the microstructure and mechanical properties of these materials. Conventional approaches to process qualification are laborious and time consuming, requiring innovative approaches and technologies to rapidly iterate through the process space and achieve a desired mechanical response. High throughput tension testing and large area quantitative polarized-light microscopy are leveraged to accelerate the mechanical and microstructural characterization of W-DED Ti-6Al-4V. Large-area quantitative polarized light microscopy provides a much-needed solution to rapidly characterize large columnar prior-beta columnar grains and identify processes that result in deleterious continuous alpha grains. Results are discussed in the context of process optimization, qualification, and verification through both witness sampling and destructive part analysis.SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525
11:10 AM Invited
Thermal Model of Hot-wire Additive Manufacturing of Ti-6Al-4V: Lonnie Smith1; Andrew Huck1; Petrus Pistorius1; 1Carnegie Mellon University
Laser hot-wire additive manufacturing is a promising method to construct relatively large components. The as-built microstructure is the result of multiple heating and cooling cycles, resulting from the thermal effect of the deposition of individual beads. In this work, a one-dimensional finite-difference model is shown to adequately capture the thermal history within Ti-6Al-4V builds consisting of stacked beads (one bead wide). In particular, the occurrence and positions of white-etching bands match the actual structure. These bands reflect positions that were reheated to a peak temperature somewhere near the beta transus reflecting nearly complete dissolution of the alpha phase. The effect of heat build-up is evident in the overall energy balance, and in the effect of delay time between passes on white-band position. Coupling the thermal history with kinetic models of phase formation upon heating and cooling provides predictions of the microstructure.