Refractory Metals 2023: Processes and Coatings - Ultimate Plus
Sponsored by: TMS Structural Materials Division, TMS: Refractory Metals & Materials Committee
Program Organizers: Brady Butler, US Army Research Laboratory; Todd Leonhardt, Rhenium Alloys Inc.; Matthew Osborne, Global Advanced Metals; Zachary Levin, Los Alamos National Laboratory
Thursday 2:00 PM
March 23, 2023
Room: Aqua E
Location: Hilton
Session Chair: Matt Osborne, Global Advanced Metals
2:00 PM Invited
ULTIMATE: Additive Manufacturing of Ultrahigh Temperature Mo-Si-B Alloys: Zahabul Islam1; Longfei Liu2; John Perepezko2; Phalgun Nelaturu2; Ankur Agrawal2; Dan Thoma2; 1Bowling Green State University; 2University of Wisconsin-Madison
To address the challenges of processing ultrahigh temperature refractory metal alloys, a novel reactive synthesis-based additive manufacturing technique has been developed to fabricate chemically uniform and dense alloys. For alloys in the Mo-Si-B system a premixed blend of molybdenum, silicon nitride, and boron nitride powder was used to manufacture alloys with designed compositions. A key challenge of this reactive synthesis technique was to design suitable process parameters that can manufacture samples with full density. To design the process parameters and build efficiency, a dimensionless number was developed. High-throughput synthesis and characterization methods using build height measurements of individual samples validated the process parameters. A correlation between the build height and dimensionless number can be used to optimize print time and control dimensional accuracy. Microstructures and properties indicate refined structures with structural integrity. The results demonstrate an effective strategy to use reactive synthesis for additively manufactured Mo-Si-B alloys.
2:30 PM
Ultimate: Affordable, Durable Precipitation Strengthened Refractory High Entropy Alloys for Use at 1300 Celsius and Above: Michael Gao1; Michael Kirka2; Michael Widom3; Chantal Sudbrack1; Vishnu Raghuraman3; Saro San1; Saket Thapliyal2; Chris Ledford2; Julio Rojas2; Brian Jordon2; Paul Jablonksi1; David Alman1; 1National Energy Technology Laboratory; 2Oak Ridge National Laboratory; 3Carnegie Mellon University
In this U.S. Department of Energy ARPA-e Ultimate Program funded project, high throughput CALPHAD, targeted atomic level simulations, and rapid validation experiments were used to design an additive manufacturable, precipitation strengthened refractory high entropy alloy (RHEA) for use at temperatures exceeding 1300 Celsius. High throughput CALPHAD was used to identify alloy systems where carbides form during solid state necessary for the precipitation of fine carbides needed for elevated strength. Intrinsic ductility calculations and ab-initio tensile tests simulations were utilized to identify alloys that also possessed the requisite ductility and toughness. Arc melted buttons (250 gram) were produced from promising compositions for validation of the computational simulations, microstructure and mechanical property evaluation, and single pass beam experiments to simulate direct energy deposition (DED) additive manufacturing (AM) and to assess manufacturability. Reported are the results of DED-AM trials, microstructure assessment, and mechanical performance of down-selected compositions.
2:50 PM
ULTIMATE: Arc Melting and Additive Manufacturing of Refractory Complex Concentrated Alloys and Composites: Fei Wang1; Xin Chen1; Bai Cui1; Michael Gao2; Shanshan Hu3; Xingbo Liu3; Dongsheng Li4; 1University of Nebraska Lincoln; 2National Energy Technology Laboratory; 3West Virginia University; 4Advanced Manufacturing LLC
To develop new refractory alloys and composites that can be used as blade materials for turbine engines operated at 1300C, refractory complex concentrated alloys (RCCAs) were designed and experimentally fabricated and tested. A large number of new compositions of the single-phase RCCAs were designed based on the high throughput computational design. Experimental verification of these RCCAs was conducted by both arc melting and laser powder bed fusion. Mechanical properties, including yield strength, ductility, hardness, and creep properties, were measured at both room temperature and high temperatures. Optimized RCCA compositions with a combination of excellent mechanical properties were selected based on the experimental and simulation results. The mechanical properties of RCCAs were enhanced by the second phase of carbides.
3:10 PM
Development of Ruthenium-Based Alloy Wire for Highly Efficient OLED Vacuum Deposition: Rikito Murakami1; Kei Kamada1; Kenichi Umetsu2; Shiika Itoi3; Hiroaki Yamaguchi3; Takashi Yoshioka4; Katsunari Oikawa1; Junji Kido2; Akira Yoshikawa1; 1Tohoku University; 2Yamagata University; 3C&A Corporation; 4Sunric Co., Ltd.
In deposition cells used for organic light-emitting diode (OLED) thin film deposition, Ta wires are commonly used, however, the low electrical resistivity and its high-temperature dependence have led to poor temperature controllability. In this study, Ru-Mo-W alloy wires were fabricated by the alloy-micro-pulling method (Alloy-μ-PD) and demonstrated to have higher heating efficiency, heating controllability, and high-temperature durability at 1600°C than conventional Ta wires. In addition, we demonstrated that the wire diameter was stably controlled to ±10 μm or less over 10 m in the crystal growth, and that the wire produced by the μ-PD method can function as a resistance heating wire.
3:30 PM Break
3:45 PM
New Environmental-thermal Barrier Coatings for Ultrahigh Temperature Alloys: Hua Xie1; Victor Champagne2; Wei Zhong1; Bryson Clifford1; Yunhui Gong3; David Clarke2; Liangbing Hu1; Ji-Cheng Zhao1; 1University of Maryland; 2Harvard University; 3HighT-Tech LLC
An ultrafast high-temperature sintering (UHS) method (Science, 368 (2020) 521) was employed to perform fast exploration of new environmental-thermal barrier coatings (ETBCs) for ultrahigh temperature refractory alloys to be used in the harsh turbine environments. UHS enables ultrafast synthesis of high-melting oxide coatings, including multilayers, often in minutes instead of hours, and thus breaks through the bottleneck preventing the rapid evaluation of such coatings. UHS together with fast-fail tests as well as modeling enabled our team to cast a wide net of compositions and coating architectures in order to design and optimize 1700°C-capable coatings that have good expansion match with the substrates and are resistant to high velocity oxidizing, moisture-containing gas flows present in turbines. Dozens of ETBCs have been fabricated on both polycrystalline SiC and coated C103 Nb-based alloy substrates, and tested for stability and resistance to thermal cycling. Our project is part of the ARPA-E ULTIMATE Program.
4:05 PM
Novel Refractory Bond Coat Alloy Capable of Alumina Formation Up to 1400°C (ULTIMATE Project): Collin Holgate1; Carolina Frey1; Melina Endsley1; Akane Suzuki2; Carlos Levi1; Tresa Pollock1; 1University of California Santa Barbara; 2GE Research
Refractory alloys offer exciting opportunities to enhance the efficiency of gas turbine engines by replacing current Ni-based superalloys. However, bond coat alloys that provide oxidation protection to the current superalloys have inadequate temperature capability and are thermochemically incompatible with refractory alloys. The successful implementation of refractory alloys in the hot section of gas turbine engines will therefore require new protective bond coatings, the design of which is the focus of the presented work. Thermodynamic modeling (CALPHAD) was used to screen a large composition space, wherein a promising composition in the Nb-Si-Ti-Al-Hf space was selected and subsequently synthesized by arc melting. The alloy oxidized favorably to form alumina scales at 800°C, 1200°C, and 1400°C. Interdiffusion behavior with candidate structural Nb-Si alloys is also discussed.
4:25 PM
High Entropy Rare-earth Oxide (HERO) Coatings for Refractory Alloys: Kristyn Ardrey1; Mackenzie Ridley2; Prasanna Balachandran1; Bi-Cheng Zhou1; Patrick Hopkins1; Elizabeth Opila1; 1University of Virginia; 2Oak Ridge National Lab
A new coating concept for refractory alloys, described here, utilizes high entropy rare earth oxide (HERO) mixtures to achieve requisite coating properties. The C-type RE2O3 have cubic crystal structures and are desired for a good thermal expansion match to refractory alloys. RE2O3 are high-temperature steam-stable and readily form apatite and other silicate barrier layers during reaction with molten siliceous debris. Oxygen diffusivity in Y2O3 is orders of magnitude lower than that in yttria stabilized zirconia. Combinations of RE cations in RE2O3 with large mass and size variation reduce thermal conductivity due to increased phonon scattering. Refractory metals and RE2O3 have a stable interface due to the significantly higher stability of RE2O3 relative to refractory metal oxides. In this presentation, proof of concept results for each of these required properties will be presented. Multicomponent RE2O3 mixtures that simultaneously optimize coating properties for refractory alloys will be described.
4:45 PM
Microstructural and Compositional Evolution in the Tantalum Vanadium System: Towards Refractory Alloys for Extreme Environments: Connor Rietema1; Jibril Shittu1; Alex Baker1; Aurélien Perron1; Brandon Bocklund1; Hunter Henderson1; Scott McCall1; Joseph McKeown1; 1Lawrence Livermore National Laboratory
With the growing interest in multicomponent refractory alloys for extreme aerodynamic and aerothermal applications there is a need for further understanding of binary alloy systems. Modeling techniques that enable rapid alloy candidate down-selection like CALPHAD and machine learning necessitate high confidence phase fraction and compositional data of the simpler binary systems. Our work uses a combination of energy and wavelength dispersive spectroscopy alongside traditional and in-situ high temperature x-ray diffractometry to examine the phases present and phase compositions over an array of alloy compositions and temperatures within the Ta-V alloy system and others. We also outline the microstructural evolution and hardness of the Ta-V system and others as a function of heat treatment temperature and elemental composition providing insight into these systems for future alloy development. This work was performed under the auspices of the United States Department of Energy by Lawrence Livermore National Laboratory (LLNL) under Contract DE-AC52-07NA27344.