HEA 2023: Performance in Extreme Environments I
Program Organizers: Andrew Detor, DARPA/DSO; Amy Clarke, Los Alamos National Laboratory
Wednesday 9:00 AM
November 15, 2023
Room: William Penn Ballroom
Location: Omni William Penn
Session Chair: Sal Rodriguez, Sandia National Laboratories
9:00 AM Introductory Comments
9:05 AM Invited
Complex Alloys for Extreme Aerospace Environments: Austin Mann1; Ali Yousefiani1; Timothy Smith2; Harikirshnan Rajendran1; Atsushi Sato3; Pimin Zhang3; Yining He3; David Crudden3; 1Boeing Research & Technology; 2Nasa Glenn Research Center; 3Alloyed Ltd
Desire for ultra-high capability aerospace vehicles and systems operating in extreme environments, and the increasing maturity level of cutting-edge manufacturing technologies is quickly advancing the sophistication of component design. However, high performance designs for harsh service conditions place additional demand on the materials of construction, and can potentially outpace current state-of-the-art material capabilities. Our team has been addressing this challenge by developing complex concentrated alloys/composites and their associated powder-based methods of manufacturing for extreme environment aerospace components, specifically topologically optimized heat exchangers and turbine blades. These new classes of disruptive and ultra-high-performance material solutions are being developed in pursuit of continuous operation under moderate to high sustained stresses at temperatures ranging from 1500°F to 3300°F (with active/passive cooling), for minutes to tens of thousands of hours. Applications of these complex alloys and simulated service testing will also be described.
9:35 AM
Discovery and Development of Novel, Ultrahigh-temperature Alloys and Coatings for Jet Engine and Industrial Gas Turbine Applications: Philseok Kim1; Pankaj Trivedi1; Ashok Gidwani1; Toni Marechaux1; Christian Vandervort1; Peter de Bock1; 1ARPA-E, Department of Energy
An introduction to Advanced Research Projects Agency – Energy (ARPA-E)’s Ultrahigh Temperature Impervious Materials Advancing Turbine Efficiency (ULTIMATE) program as well as the program findings to date will be presented and discussed. The ULTIMATE program aims to develop ultrahigh temperature materials for gas turbines used in power generation and aviation industries, enabling them to operate continuously at 1300°C (2372°F) in a stand-alone material test environment, or with coatings, enabling gas turbine inlet temperatures of 1800°C (3272°F) or higher. The successful materials must be able to withstand not only the highest temperature in a turbine but also the extreme stresses imposed on turbine blades. Manufacturing processes for turbine components using these novel alloys are concurrently developed, enabling complex geometries that can be seamlessly integrated in the system design. Progress in environmental barrier coatings and thermal barrier coatings will also be presented.
9:55 AM
Mechanical and Tribological Properties of (AlCoCrNiSi)100-xNx Thin Films: Tongyue Liang1; Sima Alidokht2; Richard Chromik1; 1McGill University; 2Memorial University of Newfoundland
Thin films of (AlCoCrNiSi)100-xNx were deposited on silicon wafers using pulsed DC magnetron sputtering technique, with nitrogen gas flow ratios (RN) of 0, 0.33, and 0.50. The structure and properties of the films were analyzed for elemental composition, surface and cross-sectional morphology, microstructures, roughness, and mechanical properties. Using nanoindentation, the coating deposited at RN = 0.50 had the highest hardness (10.7±0.5 GPa) and reduced modulus (176±5 GPa). Microtribology testing was conducted using a 20 μm radius spherical diamond tip under ambient air, applying six loads ranging from 0.5 mN to 9 mN. The worn surfaces were characterized using atomic force microscopy. The coefficient of friction was evaluated to investigate the elastic and plastic behaviors of the coating using Schiffman's model. The coating without nitrogen displayed a predominant plastic behavior during the initial cycles, while the coating deposited at RN = 0.33 demonstrated a more elastic behavior, particularly at lower loads.
10:15 AM
Novel High-entropy Metal-ceramic Composites with Superior Mechanical Properties: Bai Cui1; Xin Chen1; Fei Wang1; Xiang Zhang1; Shanshan Hu2; Xingbo Liu2; Samuel Humphry-Baker3; Michael Gao4; Lingfeng He5; Yongfeng Lu1; 1University of Nebraska-Lincoln; 2West Virginia University; 3Imperial College London; 4National Energy Technology Laboratory; 5North Carolina State University
A new concept of high-entropy metal-ceramic composites (HEMCC) has been proposed that combines the outstanding physical properties of both high-entropy alloy (HEA) and high-entropy ceramic (HEC). As the first HEMCC system, to the best of our knowledge, TiTaNbZr-(TiTaNbZr)C, has been developed by a powder metallurgy process. Both the HEA and HEC phases with non-equimolar compositions exhibit body-centered cubic (BCC) and rock-salt B1 crystal structures, respectively, and both have non-equimolar compositions. With the increase of the HEC phase in HEMCC, the hardness is enhanced while the density and fracture toughness are decreased. HEA50C shows a favorable combination of flexural strength and fracture toughness at room temperature and a high compressive strength at 1300 ºC. The optimized mechanical performance of HEMCC might be attributed to the combination of the ductile HEA and strong HEC phases, smaller grain size, and crack trapping at HEC/HEA interfaces.
10:35 AM Break
10:55 AM
Effects of Si and B Contents on the Microstructure and Mechanical Properties of Boron Enhanced Complex Concentrated Silicides: Willian Pasini1; Adelajda Polkowska1; Rafał Nowak1; Wojciech Polkowski1; 1Krakow Institute of Technololgy
Designing and developing new high-temperature structural materials surpassing Ni superalloys limitations is a significant challenge in materials science. Boron Enhanced Complex Concentrated Silicides (BECCSs) – a novel concept of high entropy-derived ultra-high temperature materials combines the concepts of RM-Si-B silicides, RCCAs, and ultra-high-temperature borides building a bridge between lightweight, oxidation-resistant but brittle silicides and high-strength, refractory metallic alloys. A Central Composite Design (CCD) were employed to explore the effect of Si and B additions on BECCSs microstructure, mechanical response and performance. Nine different compositions (NbMo0.9W0.3Ta0.4Ti1.8)1-x-ySixBy, have been manufactured by arc-melting, while their SEM/EDS/EBSD, micro-indentation methods, were used to evaluate the microstructure and mechanical properties at room temperature. The results allow for the identification of specific phase constituents, and it has also been demonstrated that switching from BCC solid solutions to intermetallic-based alloys results in a significant increase in hardness.
11:15 AM
Sulfidation Behavior of NbTiCr Multicomponent Alloy: Isabela Dainezi1; Brian Gleeson2; Carlos Rovere1; 1Federal University of Sao Carlos; 2University of Pittsburgh
The new properties of multicomponent alloys show promising results that are relevant to various applications, such as strategic industries. Currently, one challenging aspect in area of materials for harsh service environments is to design alloys that are resistant to sulfidation at high temperatures. Sulfur is one of the most common corrosive contaminants in high-temperature industrial environments, including fuel and feedstocks. The principal aim of this study was to investigate the sulfidation behavior of a NbTiCr alloy in the as-cast and hot-isostatically pressed (HIP) conditions in a reducing H2S/H2 gas mixture at different temperatures. The sulfidation behavior of NbTiCr was compared to as-received HAYNES 188 at temperatures between 600 and 1100°C and exposures for 20 to 100 hours. The preliminary results show that the multicomponent alloy has significantly superior sulfidation resistance compared to the conventional 188 alloy. The modes of degradation will be compared and assessed in this presentation.
11:35 AM
Influence of the Fabrication Process on the Corrosion Behavior of Two High Entropy Alloys in Molten Solar Salt: Paula Olmos1; Rita Carbajales1; Celia Sobrino1; 1Universidad Carlos III de Madrid
One field where the development of materials resistant to extreme environments is crucial is advanced power generation systems, such as Solar Concentrated Power (CSP) plants, which employ molten salt (solar salt: 40% KNO3/60% NaNO3) as a thermal storage medium. This study examines the feasibility of using HEAs as a material for components exposed to these solar salts, assessing their corrosion resistance in this medium. The study includes an original Co-free composition, FeCrMoAlTiNi,, and another eutectic composition, AlFeCrCoNi, previously reported to exhibit good corrosion results in marine environments. HEAs were produced using Arc Melting and Powder Metallurgy techniques. The latter processing route was chosen to achieve greater microstructural control, using rapid and ultra-rapid field-assisted sintering methods, such as thermomechanical sintering, Spark Plasma Sintering (SPS), and Electrical Resistance Sintering (ERS). The results provide insight into the effect of processing route on corrosion resistance, demonstrating an improvement over the reference material (stainless steel).
11:55 AM
Development of High Entropy Alloy Based Coatings via Directed Energy Deposition (DED) Additive Manufacturing for Nuclear Applications: Subhashish Meher1; Mohan Nartu1; Chinthaka Silva1; Isabella van Rooyen1; Calvin Downey2; Luis Nunez2; Michael Maughan3; Yogesh Sighla3; 1Pacific Northwest National Laboratory; 2Idaho National Laboratory; 3University of Idaho
Advanced coatings systems have been utilized to protect bulk components from extreme environments such as thermal and mechanical stresses, corrosion and irradiation in nuclear reactors. The current work focuses on development of new coating materials via advanced manufacturing (AM) techniques and their advanced characterization. Here, a powder-based directed-energy deposition (DED) technique is used to synthesize functionally graded high entropy alloys (HEAs) between three commonly industrial alloys: IN718, SS316L, and 70Co30Cr. The HEAs are of interest due to their possible high strength and hardness, wide operational temperature ranges, creep and diffusion resistance, and radiation resistance. Samples are fabricated with a 1:1:1 ratio of IN718, SS316L, and 70Co30Cr where IN718 is a source of nickel and chrome, SS316 is a source of iron and chrome, and 70Co30Cr is a source of cobalt and supplemental chrome. For each sample, overall build quality, microstructure, compositional distribution, phases analyses were studied by transmission electron microscopy.