Additive Manufacturing for Energy Applications III: Characterization of Additive Manufactured Products
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 8:30 AM
March 15, 2021
Room: RM 1
Location: TMS2021 Virtual
Session Chair: Subhashish Meher, Idaho National Laboratory
8:30 AM Cancelled
Microstructural, Mechanical, and Corrosion Behavior of a High Entropy Alloy (HEA) Designed for Harsh Aqueous Environments: Nikole Kucza1; Martin Morra1; Kosuke Kuwabara2; 1GE Global Research; 2Global Research & Innovative Technology Center GRIT
A CoCrFeNiTiMo-based high entropy alloy (HEA) was designed for corrosion resistance and successfully printed, using selective laser melting (SLM), into near-net-shape hardware and test-blocks. Materials properties were benchmarked (microstructure, mechanical, and corrosion) against conventional cast and wrought alloys used in subsea O&G applications. All specimens received a post-processing heat treatment to relieve stress and precipitate the strengthening phases. Mechanical properties at room temperature yield the following: impact energy of 39.7-40.9 J, yield strength of 890-892 MPa, and the UTS of 1420 – 1459 MPa. Fracture toughness was good with very slow fatigue crack growth rates. Aqueous corrosion resistance is excellent (< 1 mpy) in a near neutral pH (3.5 wt.% NaCl) and acidic oxidizing (10 wt.% HNO3) environments and comparable to conventional superalloys in acidic reducing (10 wt.% HCl) environments. Results so far suggest the build orientation and location on the build plate have little effect on properties and microstructure.
8:50 AM
Microstructural Stability and Creep Behavior of an Additively Manufactured Al-Ce-Ni-Mn Alloy: Richard Michi1; Kevin Sisco2; Sumit Bahl1; Jonathan Poplawsky1; Lawrence Allard1; Ryan Dehoff1; Alex Plotkowski1; Amit Shyam2; 1Oak Ridge National Laboratory; 2University of Tennessee, Knoxville
Additive manufacturing provides opportunities for development of aluminum alloys that may be used in the 250–400 °C temperature range. These alloys have long been sought as potential replacements for steels, Ti alloys, and Ni-based superalloys, providing weight and/or cost reductions. In this presentation, unique microstructural features in an additively manufactured Al-11.3Ce-3.2Ni-1.15Mn (wt.%) alloy will be related to its promising elevated-temperature mechanical properties. In addition to a discussion of creep deformation mechanisms, alloy microstructural stability is evaluated at 300–400 °C by electron microscopy in conjunction with microhardness measurements. Insights into atomic-scale phase composition and interfacial structures from atom-probe tomographic (APT) analyses are also discussed. APT was conducted at the Center for Nanophase Materials Sciences (CNMS), which is a U.S. DOE Office of Science user facility.
9:10 AM
Microstructure-property of a Novel 9Cr Ferritic Martensitic Steel via Additive Manufacturing Directed Energy Deposition: Weicheng Zhong1; Lizhen Tan1; Kevin Field2; Niyanth Sridharan3; Ying Yang1; Kurt Terrani1; 1Oak Ridge National Laboratory; 2University of Michigan, Ann Arbor; 3Lincoln Electric Company
A novel high Mn ferritic martensitic (FM) steel was designed and fabricated via additive manufacturing (AM) using the directed energy deposition technology for nuclear applications. The goal of this work is to evaluate the microstructure and mechanical performance of the as-built AM steel, in comparison with the normalized and tempered (N&T) FM steels. Tensile tests were performed from room temperature (RT) to 700℃, demonstrating the superior tensile strength of AM FM steels (over ~500MPa higher RT yield strength) than the N&T steels at all investigated temperatures, compromised with some ductility reductions. Multiscale microstructural characterization using EBSD and TEM indicated the refined prior austenite grain structure in the AM steel as a result of cyclic heating and cooling history. The high-density (1E22 m-3) refined precipitates and high-density (1E15 m-2) dislocations were correlated with the mechanical response of the AM steel.
9:30 AM
The Effect of Grain Orientation on Nanoindentation Behavior of Selective Laser Melted Austenitic Stainless Steel: Sravya Tekumalla1; Sudharshan Raman1; Matteo Seita1; 1Nanyang Technological University
Due to the directional cooling rates and thermal gradients involved, selective laser melting (SLM) yields metal parts with complex solidification microstructures that exhibit anisotropic mechanical properties, even in normally isotropic materials such as stainless steel 316L (SS316L). In this work, we present a detailed study of the anisotropic deformation behavior of SLM SS316L as a function of grain orientation using instrumented nanoindentation. We produce near-single crystal samples oriented along the <111>, <101>, and <100> crystallographic directions and study their hardness and room temperature creep. We find that the {111} orientation exhibits the highest hardness, while the {100} orientation exhibits the greatest resistance to creep deformation. We correlate the mechanical anisotropy to the propensity of different grain orientations for deformation slip and twinning and elucidate the suppression of deformation twinning in {100}. Our work enables translation of the mechanical deformation behavior to effective design of structural components made from SLM SS316L.
9:50 AM
Quality Evaluation of As-printed Wire Arc Additively Manufactured 316L Stainless Steel Blocks: Yukinori Yamamoto1; Lizhen Tan1; Ying Yang1; Andrzej Nycz1; Mark Noakes1; Yousub Lee1; Luke Meyer1; William Carter1; Thak Sang Byun1; Ryan Dehoff1; Kurt Terrani1; 1Oak Ridge National Laboratory
Thick-wall blocks have been produced through wire arc additive manufacturing with heat-resistant steel wires, targeting development of a fabrication route for thick-wall reactor pressure vessels for future nuclear reactors to be operated at 600°C or above in the “as-printed” condition. A commercial 316L stainless steel (UNS31603) wire was selected for the first attempt, as one of the nuclear-grade austenitic stainless steels. Controlling the microstructure evolution during printing process would be highly important to achieve balanced mechanical properties such as hardness, toughness, tensile, and creep properties. The quality of the printed blocks, in terms of microstructure and mechanical properties, was correlated with the printing conditions including weld parameters, toolpath patterns, heating-and-cooling cycles, etc. Modification of the alloy composition was also initiated for controlling the solidification path to optimize the microstructure in as-printed components. Research sponsored by the U.S. Department of Energy, Office of Nuclear Energy, the Transformational Challenge Reactor (TCR) program.
10:10 AM
Elevated Temperature Dip in Tensile Elongation of an Additively Manufactured Al-Cu-Ce Alloy: Sumit Bahl1; Kevin Sisco2; Jonathan Poplawsky1; Richard Michi1; Lawrence Allard1; Ryan Dehoff1; Alex Plotkowski1; Amit Shyam1; 1Oak Ridge National Laboratory; 2University of Tennessee-Knoxville
Higher temperature aluminum alloys are attractive materials that afford lightweighting solutions to replace heavier alloys. Additive manufacturing is increasingly investigated as a means to develop new aluminum alloys with superior mechanical properties, benefitting from the unique microstructures produced in bulk form that have been largely unattainable by conventional material processing techniques. In this work, we describe a dip in tensile elongation noted at elevated test temperatures in an Al-Cu-Ce alloy fabricated with selective laser melting. The dip in elongation is related to the concomitant dip in strain rate sensitivity of the alloy. The results of multiscale microstructural characterization are discussed to explain plausible reasons for the dip in strain rate sensitivity and tensile elongation.
10:30 AM
Microstructure and Properties Comparison for 316L Wire-fed Laser Metal Deposition AM Under Vacuum Conditions: Nicholas Brubaker1; Nicolene van Rooyen2; Hussam Ali1; Mark Jaster3; Indrajit Charit1; Michael Maughan1; 1University of Idaho; 2 University of Idaho; 3Premier Technology
Wire feedstock laser metal deposition (WFLMD) is proposed to have several advantages over other metal additive processes in energy materials applications. These advantages include lower feedstock cost, low waste, improved mechanical properties, improved microstructure, and high deposition rate. For adoption of WFLMD in energy and other high value applications, mechanical properties and accompanying microstructure must be assessed and optimized. The goal of this work is to compare properties of 316L stainless steel produced by LMD under both shielding gas deposition and vacuum conditions. The WFLMD process is discussed. Hardness mapping, tensile strength, and microstructure are compared to conventionally processed 316L and 316L deposited via other AM techniques.
10:50 AM
Advances in Digital Light Printing for Energy Applications: Donna Guillen1; Patrick Moo1; Michael Shaltry1; Robert O'Brien1; 1Idaho National Laboratory
The transformation from an economy heavily reliant on fossil fuels to carbon-free energy generation has sparked a demand for low-cost, highly optimized functional materials. The physical and chemical properties of several ceramics and metals make these materials useful for many applications at the nexus of energy, including agronomy, ecology, transportation, manufacturing, and industrial processes. Our team has been researching and developing new ways of structuring ceramics and metals. 3D printing technology provides unprecedented flexibility in the design of materials and components. Composition and particle size are key variables the influence the printing process. Optimum sintering schedules are identified and the mechanical properties and performance of the printed materials are characterized.