Additive Manufacturing for Energy Applications III: Additive Manufacturing Processing
Sponsored by: TMS Structural Materials Division, TMS: Additive Manufacturing Committee, TMS: Nuclear Materials Committee
Program Organizers: Isabella Van Rooyen, Pacific Northwest National Laboratory; Indrajit Charit, University of Idaho; Subhashish Meher, Idaho National Laboratory; Michael Kirka, Oak Ridge National Laboratory; Kumar Sridharan, University of Wisconsin-Madison; Xiaoyuan Lou, Purdue University

Monday 2:00 PM
March 15, 2021
Room: RM 1
Location: TMS2021 Virtual

Session Chair: Indrajit Charit, University of Idaho


2:00 PM  Invited
Metal Additive Manufacturing for Energy Industries: Edward Herderick1; 1Ohio State University
    Additive manufacturing has captured the imagination of the industrial energy community with its potential for radical improvements in design and performance. This presentation will provide a perspective on qualification and certification of metal AM components and including state of the art updates. Activities at OSU including multiple laser powder bed fusion, in process monitoring, and product development will be included. Concluding remarks will introduce a roadmap for accelerating the introduction of metal AM parts for critical applications.

2:20 PM  Invited
Laser Powder Bed Fusion of Grade 300 Maraging Steel for Tooling Applications: Peeyush Nandwana1; Rangasayee Kannan1; Donovan Leonard1; Derek Siddel1; Chase Joslin1; Ryan Dehoff1; 1Oak Ridge National Laboratory
    In 2018, the industrial sector accounted for about 22% greenhouse gas emissions in the U.S. of which significant emissions are a direct result of various manufacturing activities. This presents a unique opportunity for additive manufacturing (AM) to indirectly play a key role in minimizing emissions and improving energy efficiency. For example, the fabrication of tools with conformal cooling channels can shorten the tooling cycle times up to 25% and at the same time enhance the tool life, compared to conventionally welded tools that undergo premature failure. We present that segregation in the laser powder bed fusion of a Ti-free Grade 300 maraging steel can be leveraged to develop single-step heat treatments for achieving superior strength and ductility compared to multi-step conventional heat treatments. Further, we discuss the optimization strategy for optimizing the heat treatments. Finally, a case study on the fabrication of an injection mold tool will be presented.

2:40 PM  
Additive Manufacturing of Zr-modified Aluminum Alloy 6061 by Laser-powder Bed Fusion: Abhishek Mehta1; Le Zhou1; Holden Hyer1; Thinh Huynh1; Sharon Park1; Devin Imholte2; Nicolas Woolstenhulme2; Daniel Wachs2; Yongho Sohn1; 1University of Central Florida; 2Idaho National Laboratory
    Minor addition of Zr grain refiner has been documented to suppress the hot cracking tendency of the commercial aluminum alloys in laser powder bed fusion (LPBF) additive manufacturing. In this work, printability/buildability of commercial AA6061 and modified AA6061 with 1 wt.% Zr was examined as functions of laser power (200 – 350 W) and scan speed (100 – 1800 mm/s) using gas atomized alloy powders. Cracking observed in LPBF AA6061 disappeared with the addition of Zr, and AA6061+Zr samples with density greater than 99.9% was obtained at optimum LPBF parameters identified. Mechanical properties of the dense, Zr-modified AA6061 specimens were measured for as-built specimens, and after traditional two-step T6 and modified three-step T6 heat treatment. Underlying mechanisms in buildability, enhanced hardness, strength and ductility will be presented and discussed with respect to those of conventionally manufactured and heat treated AA6061.

3:00 PM  
Harnessing a High Energy, Superconducting Electron Beam for Additive and Far-from-Equilibrium Manufacturing: Adam Duzik1; Justin Hill1; 1Mainstream Engineering Corporation
    Superconducting electron linear accelerators open up new opportunities for advanced materials processing. High energy electrons penetrate deeper within materials, increase the processing depth and rate and enables production of far-from-equilibrium materials and selective processing within a material surface and subsurface. With support from the Office of Naval Research, NASA, and DoE, Mainstream Engineering commissioned a superconducting linear electron accelerator to investigate advanced materials processing and additive manufacturing. The goal of Mainstream's Electron Beam Enabled Advanced Manufacturing (EBEAM) center is to develop unique, far-from-equilibrium materials and alleviate significant technological deficiencies. We will present results of irradiating various metals and their unique material properties. Monte Carlo simulations electron beam and sample interaction were used to optimize the processing parameters and study far-from-equilibrium processing conditions. Applications include stainless steel additive manufacturing for small modular nuclear reactors and dissimilar metal bonding of corrosion-resistant cladding for next-generation molten salt reactors.

3:20 PM  Invited
Novel Aspects of multi-Wire Arc Additive Manufacturing for Large Component Fabrication for Extreme Environments and New Alloy Discovery: Thomas Lillo1; Nathan Huft1; Denis Clark2; Michael Glazoff1; Joel Simpson1; 1Idaho National Lab; 2DEClark Welding Engineering, PLLC
    Additive manufacturing using fusion arc welding, specifically, gas metal arc welding (GMAW) or gas tungsten arc welding (GTAW), is commonly referred to as wire arc additive manufacturing (WAAM). In this process, a single welding filler wire is used to build near-net shaped structures and components. Distinct advantages can be obtained if additional filler wires of different composition are added to the WAAM process, producing multi-wire arc additive manufacturing (m-WAAM). Controlled, relative feed rates of the different wires allow compositionally-graded deposits. Use of this capability in component fabrication for harsh environments as well as alloy discovery – including discovery of high entropy alloys – will be discussed. Preliminary results also will be presented relating to thermodynamic modeling of equilibrium phases, calculation of the composition-dependent coefficient of thermal expansion, microstructural characterization, mechanical property characterization (including the influence of build strategy on residual stress/distortion and creep behavior) and limitations of the m-WAAM process.

3:40 PM  
Efficient Production of a High-performance Dispersion Strengthened, Multi-principal Element Alloy: Timothy Smith1; Aaron Thompson1; Timothy Gabb1; Christopher Kantzos1; 1NASA Glenn Research Center
    Additive manufacturing currently facilitates new avenues for materials discovery that have not been fully explored. Here we reveal how additive manufacturing can be leveraged to produce oxide dispersion strengthened (ODS), multi-principal element alloys (MPEA) without the use of traditional mechanical alloying or chemical reactions. This new processing technique employed resonant acoustic mixing to coat an equiatomic NiCoCr powder with nano-scale yttrium oxides. Then, through laser powder bed fusion (L-PBF), the coated powder was successfully consolidated into 99.9% dense parts. Microstructural analysis confirmed the successful incorporation and dispersion of nano-scale oxides throughout the build volume. Furthermore, high temperature mechanical testing of the ODS alloys showed significant improvements in strength and ductility over the baseline NiCoCr. As a result, this recently discovered processing route opens a new alloy design and production path that is synergistic between additive manufacturing and dispersion strengthening, possibly enabling a new generation of high-performance alloys for energy applications.

4:00 PM  
Investigation of the Effect of Laser Energy Density on Properties of Additively Manufactured Tungsten Lattices: Carly Romnes1; Omar Mireles2; James Stubbins1; 1University of Illinois at Urbana-Champaign; 2NASA Marshall Space Flight Center
    Additive manufacturing (AM) offers the unique capability to fabricate complex geometries and control fundamental material properties during production. AM is particularly promising for manufacturing complex geometries from tungsten and other refractory metals, which are difficult to form using traditional processes. In this study, tungsten lattices of approximately 5x5x5 mm3 were additively manufactured using various laser energy densities. Applications for these tungsten lattices include catalyst beds for monopropellant and green propulsion, insulation, wicking structures, and heat pipes. Lattice strut thickness and pore size were characterized using optical microscopy. Compression tests were performed to determine the effect of laser energy density on lattice strength. Our presentation will discuss the results of these experiments and their implications. This work will help inform the development of tungsten lattices for propulsion systems as well as nuclear systems, where tungsten is already of major interest for fusion systems for plasma facing and high thermal load structures.

4:20 PM  
Toward Part Qualification: Thermal Signature Analysis Using Wavelet Transform in Metal Additive Manufacturing: Sujana Chandrasekar1; Jamie Coble1; Amy Godfrey1; Serena Beauchamp1; Fred List2; Vincent Paquit2; Sudarsanam Babu1; 1University of Tennessee; 2Oak Ridge National Laboratory
    A key challenge in increased adoption of Additive Manufacturing for critical energy applications is part qualification for different load conditions. Additively manufactured parts exhibit variation in material properties due to inherent variation in thermal process cycles, associated primarily with scan strategy and part geometry. To qualify parts, it is essential to identify regions having similar thermal cycles and those that are anomalous. We develop an in-situ monitoring method for the laser powder bed fusion process using infrared (IR) data collected during the build process. Our monitoring algorithm is built on the wavelet transform and used to identify similar thermal cycles based on IR data. Wavelet transform enables multiresolution analysis and can be used both for pattern recognition and anomaly detection. In-situ monitoring give us the ability to identify thermally similar regions based on scan strategy and also identify overheated regions. This approach is a promising step toward data-driven part qualification.

4:40 PM  
Effective Thermal Conductivity of Additively Manufactured Metal Matrix Composite: Saereh Mirzababaei1; Venkata Vinay Krishna Doddapaneni1; Kijoon Lee1; Sriram Manoharan1; Chih-hung Chang1; Brian K. Paul1; Somayeh Pasebani1; 1Oregon State University
    Metal additive manufacturing is increasingly evolving from production of single-material into manufacturing of composite materials for various high-value sectors. While strength of the additive manufactured parts is a common concern, thermal properties are highly relevant to many heat transfer-related and energy applications. However, the effects of porosity and microstructure on the effective thermal conductivity of additive manufactured composites has not been extensively investigated. This work investigates the effective thermal conductivity of laser-melted copper-reinforced stainless steel 316L matrix. Ball milling of 316L with copper powder coupled with selective laser melting technology was utilized to additively manufacture the metal matrix composite. Several structural analytical models for predicting the effective thermal conductivity were compared with thermal conductivity measurements of additively-manufactured coupons using a laser flash method. The effect of porosity, volume fraction, shape, and size of the second phase (copper) on the thermal conductivity of the composite material were evaluated.