17 20 25 P. 12 MARCH 2023 | VOL 181 | NO 2 Predicting Mechanical Properties of High Entropy Alloys New Applications for Horizontal Contact Drying SMST NewsWire and HTPro Newsletter Included in This Issue NEXT GENERATION PROPULSIONMETHODS AEROSPACE MATERIALS AND TESTING
17 20 25 P. 12 MARCH 2023 | VOL 181 | NO 2 Predicting Mechanical Properties of High Entropy Alloys New Applications for Horizontal Contact Drying SMST NewsWire and HTPro Newsletter Included in This Issue NEXT GENERATION PROPULSIONMETHODS AEROSPACE MATERIALS AND TESTING
2023 INTERNATIONAL MATERIALS, APPLICATIONS & TECHNOLOGIES OCTOBER 16–19, 2023 | HUNTINGTON PLACE | DETROIT, MICHIGAN REGISTRATION OPENS SPRING 2023! imatevent.org ADVANCED MATERIALS AND MANUFACTURING TECHNOLOGIES ASM International is the only society that unites di erent market segments that span the entire materials world and connects industry, academia, and government to solve global materials challenges. Core programming from all six of ASM’s A iliate Societies will serve as the backbone of IMAT technical sessions. Here what’s you can expect with the Heat Treat and MPT co-location: 5000+ attendees Over 700 technical presentations, keynotes, and panel discussions More than 500 exhibits 4 days of technical programming 2.5 days of exposition Education courses and workshops Networking events Sessions organized by the IDEA Committee Programming and activities for emerging professionals We’re bringing together all the global expertise you need to tackle modern materials challenges! Technical program details will be made available in summer 2023. SAVE THE DATE ORGANIZED BY: PARTNERED WITH: CO-LOCATED WITH:
41 HTPro The official newsletter of the ASM Heat Treating Society (HTS). This supplement focuses on heat treating technology, processes, materials, and equipment, along with HTS news and initiatives. NEXT GENERATION AIRCRAFT PROPULSION: A PRATT & WHITNEY APPROACH Sean Bradshaw Aircraft engines that minimize fuel consumption and operate on sustainable aviation fuels are key to meeting the air transportation sector’s commitment to net zero CO2 emissions by 2050. 12 A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 2 A plane landing in front of the Fort Worth, Texas, skyline. Courtesy of Dreamstime. On the Cover: 54 ASM NEWS The latest news about ASM members, chapters, events, awards, conferences, affiliates, and other Society activities. 23 AEROMAT SHOW PREVIEW The 34th AeroMat Conference and Exposition joins up with AeroTech in Fort Worth, Texas.
4 Editorial 5 Research Tracks 5 Feedback 10 Machine Learning 11 Energy Trends 6 Metals/Polymers/Ceramics 8 Testing/Characterization 67 Editorial Preview 67 Special Advertising Section 67 Advertisers Index 68 3D PrintShop TRENDS INDUSTRY NEWS DEPARTMENTS Check out the Digital Edition online at asminternational.org/news/magazines/am-p ASM International serves materials professionals, nontechnical personnel, and managers wordwide by providing high-quality materials information, education and training, networking opportunities, and professional development resources in cost-effective and user-friendly formats. ASM is where materials users, producers, and manufacturers converge to do business. Advanced Materials & Processes (ISSN 0882-7958, USPS 762080) publishes eight issues per year: January/February, March, April, May/June, July/August, September, October, and November/December, by ASM International, 9639 Kinsman Road, Materials Park, OH 44073-0002; tel: 440.338.5151; fax: 440.338.4634. Periodicals postage paid at Novelty, Ohio, and additional mailing offices. Vol. 181, No. 2, MARCH 2023. Copyright © 2023 by ASM International®. All rights reserved. Distributed at no charge to ASMmembers in the United States, Canada, and Mexico. International members can pay a $30 per year surcharge to receive printed issues. Subscriptions: $499. Single copies: $54. POSTMASTER: Send 3579 forms to ASM International, Materials Park, OH 44073-0002. Change of address: Request for change should include old address of the subscriber. Missing numbers due to “change of address” cannot be replaced. Claims for nondelivery must be made within 60 days of issue. Canada Post Publications Mail Agreement No. 40732105. Return undeliverable Canadian addresses to: 700 Dowd Ave., Elizabeth, NJ 07201. Printed by LSC Communications, Lebanon Junction, Ky. 17 DESIGN TOOL PREDICTS MECHANICAL PROPERTIES AND HIGH-TEMPERATURE PERFORMANCE OF HIGH-ENTROPY ALLOYS Yu Zhong New software helps predict properties of high-entropy alloys and takes the guesswork out of choosing a composition. 20 TECHNICAL SPOTLIGHT FEATURES AND BENEFITS OF HORIZONTAL CONTACT DRYING The dynamic, high-temperature process of horizontal contact drying makes it possible to treat bulk materials more efficiently and evenly than traditional drying ovens and rotary kilns. 25 SMST NewsWire The official newsletter of the International Organization on Shape Memory and Superelastic Technologies (SMST). This biannual supplement covers shape memory and superelastic technologies for biomedical, actuator applications, and emerging markets, along with SMST news and initiatives. FEATURES MARCH 2023 | VOL 181 | NO 2 A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 3 17 25 29 20 29 SMST ENTREPRENEURIAL WORKSHOP PREVIEW The SMST Entrepreneurial Workshop includes the SMArt Tank session in Fort Worth, Texas.
4 A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 ASM International 9639 Kinsman Road, Materials Park, OH 44073 Tel: 440.338.5151 • Fax: 440.338.4634 Joanne Miller, Editor joanne.miller@asminternational.org Victoria Burt, Managing Editor vicki.burt@asminternational.org Frances Richards and Corinne Richards Contributing Editors Anne Vidmar, Layout and Design Allison Freeman, Production Manager allie.freeman@asminternational.org Press Release Editor magazines@asminternational.org EDITORIAL COMMITTEE Adam Farrow, Chair, Los Alamos National Lab John Shingledecker, Vice Chair, EPRI Somuri Prasad, Past Chair, Sandia National Lab Beth Armstrong, Oak Ridge National Lab Margaret Flury, Medtronic Surojit Gupta, University of North Dakota Nia Harrison, Ford Motor Company Michael Hoerner, KnightHawk Engineering Hideyuki Kanematsu, Suzuka National College of Technology Ibrahim Karaman, Texas A&M University Ricardo Komai, Tesla Bhargavi Mummareddy, Dimensional Energy Scott Olig, U.S. Naval Research Lab Christian Paglia, SUPSI Institute of Materials and Construction Amit Pandey, Lockheed Martin Space Satyam Sahay, John Deere Technology Center India Kumar Sridharan, University of Wisconsin Jean-Paul Vega, Siemens Energy Vasisht Venkatesh, Pratt & Whitney ASMBOARDOF TRUSTEES David B. Williams, President and Chair Pradeep Goyal, Senior Vice President Navin Manjooran, Vice President Judith A. Todd, Immediate Past President John C. Kuli, Treasurer Burak Akyuz Amber Black Ann Bolcavage Pierpaolo Carlone Elizabeth Homan Toni Marechaux André McDonald U. Kamachi Mudali James E. Saal Sandra W. Robert, Executive Director STUDENT BOARDMEMBERS Jaime Berez, Ashlie Hamilton, Nicole Hudak Individual readers of Advanced Materials & Processes may, without charge, make single copies of pages therefrom for personal or archival use, or may freely make such copies in such numbers as are deemed useful for educational or research purposes and are not for sale or resale. Permission is granted to cite or quote fromarticles herein, provided customary acknowledgment of the authors and source is made. The acceptance and publication of manuscripts in Advanced Materials & Processes does not imply that the reviewers, editors, or publisher accept, approve, or endorse the data, opinions, and conclusions of the authors. UPLIFTING WOMEN IN AIR & SPACE Cleveland is home to an aviation treasure—the International Women’s Air and Space Museum (IWASM)— tucked away at Burke Lakefront Airport near the Rock & Roll Hall of Fame. While preparing this aerospace issue of AM&P and anticipating Women’s History Month, I toured the exhibits and was inspired by a sky full of heroic stories. Some familiar favorites came to life with rich, new factoids: Amelia Earhart (the first president of the NinetyNines committee, whose future members helped establish IWASM), Katharine Wright (called “the third member of the team” in reference to her Dayton brothers), and Sally Ride (STEM education leader). The earliest exhibit features Harriet Quimby, America’s first licensed woman pilot. She also was the first woman to fly the English Channel solo in 1912. With World War II came the formation of the Women Airforce Service Pilots (WASP), a civilian group of flyers who assisted with transport missions. But it wasn’t until 1977 that legislation was signed acknowledging their veteran status. And finally, in 2010, surviving WASP members were awarded the Congressional Gold Medal. The trio of brilliant, Black mathematicians featured in the 2016 movie “Hidden Figures,” were given prominent space in the museum for their pioneering roles at NASA in the 1950s and ‘60s. And then there were the “Mercury 13,” women who trained and passed all the tests required to be astronauts in the early 1960s but were never given the chance to join NASA’s official space program. After absorbing the stories of these pioneering women, I was struck by several commonalities among them. They all seemed to have endless passion, curiosity, and determination. A Quimby quote sums up her driving force: “I was annoyed from the start by the attitude of doubt by the spectators that I would never really make the flight. The attitude made me more determined than ever to succeed.” Launched on the wings of these aviation trailblazers, women of space with similar grit are taking giant leaps of their own. Nicole Mann became the first Native American woman in space when she launched to the International Space Station (ISS) last year. Also in 2022, Jessica Watkins became the first Black woman in a long-duration ISS mission. Her space accomplishments are just beginning. As part of the Artemis team, she is in the running to the be first woman and the first person of color to set foot on the lunar surface. No matter what happens, Watkins is happy to contribute to the team and will be pleased with whoever is selected. She says, “We are an amazing, diverse [astronaut] corps right now.” It’s taken many flight hours to get there, but what an uplifting sight. joanne.miller@asminternational.org Harriet Quimby in Blériot airplane. Courtesy of IWASM. Jessica Watkins signs crew ship. Courtesy of NASA.
A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 5 PLASTIC RECYCLING MAKES PROGRESS Using a unique catalytic approach, scientists at the DOE’s ArgonneNational Laboratory, Lemont, Ill., and Cornell University, Ithaca, N.Y., report converting post-consumer high-density polyethylene (HDPE) plastic into a fully recyclable, potentially biodegradable material with the same mechanical and thermal properties as the initial single-use plastic. Many HDPE products are produced from fossil fuels, and most post-consumer HDPE is either incinerated, placed in landfills, or lost in the environment. When it is recycled with today’s methods, the quality of the material degrades. The new approach could reduce the carbon emissions and pollution RESEARCH TRACKS / FEEDBACK We welcome all comments and suggestions. Send letters to joanne.miller@asminternational.org. SPLENDID CARTRIDGE BRASS The article on metallography of cartridge brass in the November/ December 2022 AM&P is splendid. I plan to share it with my students when we do our metallography lab on the same material. Peggy Jones, FASM Saginaw Valley State University METAL POWDER PROGRESS I am amazed by the scope of new developments covered in AM&P year after year. I was involved in the metal powder industry for many years and even wrote a number of pieces for the magazine prior to the crash of 2008. I never thought I would live to see MIM (metal injection molding) featured on your front cover (AM&P, October 2022, pictured below). Joseph Capus Consulting Editor Metal Powder Report Proposed chemical recycling of waste polyolefins and current work on transformation of waste polyethylene into chemically recyclable materials. Courtesy of J. Am. Chem. Soc., 2022. associated with HDPE by using waste plastic as an untapped feedstock and transforming it into a new material that can be recycled repeatedly with- out loss of quality. Current HDPE recycling approaches yield materials with inferior properties. The team’s alternative approach uses a series of catalysts to cleave the polymer chains into shorter pieces that contain reactive groups at the ends. The smaller pieces can then be put back together to form new products of equal value. The end groups have the additional benefit of making the new plastic easier to decompose, both in the lab and in nature. Research was funded by the DOE’s Institute for Cooperative Upcycling of Plastics (iCOUP) led by Ames National Laboratory. anl.gov. FEEDBACK
A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 6 METALS | POLYMERS | CERAMICS Fittle, the financing arm of Xerox Holdings Corp., is partnering with Velo3D Inc. to help customers finance purchases of the company’s metal additive manufacturing Sapphire printers. fittle.com. ARCH Cutting Tools Corp., Bloomfield Hills, Mich., acquired Custom Carbide Cutter Inc., Cincinnati, another cutting tools provider. ARCH serves the medical, aerospace, defense, automotive, energy, agriculture, and general industrial markets with standard and custom tooling. archcuttingtools.com. BRIEFS BONDING WITH STEEL Researchers at The University of Tokyo are pre-treating steel with an acid wash and dipping it in hot water in order to bond polymers to galvanized steel. The scientists discovered that when a polymer was applied to the treatedmetal—in a process called injection-molded direct joining—it filled in the tiny gaps and ridges between and within the needle structures, creating very strong mechanical linkages. The acid wash strips the outer passive layer on the zinc coating of the steel, which allows the hot water to form rough nanoscale needle structures on the true surface. “We found that immersion in hot water was a simple and effective method for producing nanoscale structures on the zinc coating for the polymer to adhere to, but that prior acid-washing to remove the passive layer was a WELD FILLER MATERIALS A new series of weld filler materials was created in a joint effort by the U.S. Departments of Energy and Defense, enabling onsite welding without costly, laborious heat treatments typically used to reduce residual stresses and material distortion. The novel materials could dramatically improve high-strength steel repair in vehicles, bridges, and pipelines. The invention from the U.S. Army and DOE’s Oak Ridge National Laboratory (ORNL), Tenn., solves a major problem of welded steels that occurs when hydrogen atoms enter the metal during weldingand reduce themetal’sductility, toughness, and strength. Subsequently, high tensile residual stress leads to troublesome cracking. To overcome this challenge, scientists at ORNL and DOD’s Ground Vehicle System Center partnered to invent an alloy with a unique chemical composition that can join strong steels while reducing residual stresses. The alloy’s ability to resist hydrogeninduced cracking comes from a novel phase transformation in the weld. As a weld cools, the filler material combats tensile stress, which pulls at steel’s crystalline microstructure to lengthen and break it. The phase transformation then introduces compressive stress as the weld cools. A weld filler needs to be at least as strong as the steel panels it joins. To develop the chemical composition of their pioneering, stress-compensating filler, ORNL researchers ran a theorybased model on high-performance computers. With more efficient algorithms, the computing code ran a thousand times faster than a comparable commercial code, identifying problems in one day versus nearly three years. The inventors used this process to arrive at a filler that works with structural steels of varying strengths and alloy compositions. Characterization of welded materials with neutron diffraction at the High Flux Isotope Reactor, a DOE Office of Science user facility at ORNL, showed remarkable reductions in residual stresses. ornl.gov, army.mil. Researchers developed a simple method of bonding polymers with galvanized steel to create a lightweight and durable product. Courtesy of Institute of Industrial Science, The University of Tokyo. Scientist Yiyu Wang tests and characterizes materials to determine howwelding a ects the microstructure. Courtesy of Carlos Jones/ORNL, U.S. Department of Energy.
A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 7 necessary step for this to occur,” explains scientist Weiyan Chen. By optimizing the hot water temperature and treatment time to achieve peak complexity in the nanoscale structuring, the team was able to significantly increase the tensile-shear strength compared with untreated metal. “Our process can be adapted for a wide range of hybrid joining applications, in whichmetal and plastic parts need to be permanently bonded,” says lead researcher Yusuke Kajihara. “Furthermore, our method does not use harsh chemicals or complicated procedures and thus is suited to the scale-up required for industrial application.” www.u-tokyo.ac.jp/en. MAKING MORE SUSTAINABLE ALUMINUM ALLOYS Constellium SE, Paris, will lead a new consortium of European automakers and suppliers to develop lower carbon, lower cost aluminum extrusion alloys. Sponsored by a grant from the U.K.’s Advanced Propulsion Center, the $12 million CirConAl (Circular and Constant Aluminium) project aims to maximize the use of post-consumer scrap in a new generation of highstrength alloys that emit less than two tons of CO2 per ton of aluminum produced. CirConAl is part of joint government and industry support for projects to build an end-to-end supply chain for zero-emissions vehicles in the U.K. By designing, developing, proto- typing, and testing aluminum automotive components at scale, the project is expected to demonstrate that high-strength alloys with high recycled content can meet or exceed OEM requirements, such as strength, crushability, durability, and other performance criteria. constellium.com. The consortiumwill develop scrap sorting technologies to ensure that valuable metal is recycled into new automotive solutions rather than downcycled. Courtesy of Constellium. TECHNICAL SUPPORT EPOXIES, SILICONES & UV/LED CURING CUSTOM FORMULATIONS Select the right adhesive www.masterbond.com 154 Hobart Street, Hackensack, NJ 07601 USA• +1.201.343.898 • mainmasterbond.com
8 A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 human-machine interface devices. Their new sensor consists of a silver nanowire network embedded in an elastic polymer. The polymer features a pattern of parallel cuts of a uniform depth, alternating from either side of the material—one cut from the left, followed by one from the right, followed by one from the left, and so on. The sensor gauges strain by measuring changes in electrical resistance. As the material stretches, resistance increases. The cuts in the surface of the sensor are perpendicular to the direction that it is stretched. This serves two purposes. First, the cuts allow the sensor to deform significantly. Because the cuts in the surface pull open, creating a TESTING | CHARACTERIZATION 3D IMAGING REVEALS CRACKING MECHANISM Solvingahalf-century-oldmystery, a research team from Japan’s National Institute for Materials Science identified the mechanism by which microscopic fatigue cracks grow in metals. The team found that these cracks grow along the slip planes of metallic crystals through 3D imaging of large-volume samples. Most cracks were found to be caused by a shearing force rather than the tensile forces previously thought to be responsible for the effect. The team re- cently developed an electron microscope-based analytical technique capable of high- resolution, three-dimensional crystallographic imaging of a large-volume metallic sample—100 times larger than the volume observable using conventional methods. This was the first time that fa- tigue cracks of approximately 200 µm in length were imaged three-dimensionally at high resolutions. This was achieved by applying the technique to a heat- resistant superalloy developed for use in aircraft engines. The team analyzed this image across the large sample and quantitatively determined the relationship between crack growth paths and crystalline orientations, leading to the discovery of a crack growth mechanism that differs from the mechanism conventionally assumed. www.nims. go.jp/eng. SENSITIVE STRAIN SENSORS A new, stretchable strain sensor was created by researchers at North Carolina State University, Raleigh, and features a unique combination of sensitivity and range, allowing it to detect even minor changes in strain with greater range of motion than previous technologies. The researchers demonstrated the sensor’s utility by creating new health monitoring and Triangular holes make this material more likely to crack from left to right. Courtesy of N.R. Brodnik et al./Phys. Rev. Lett. The new Vanta GX precious metal analyzer from Evident Corp., Waltham, Mass., offers a simple way to obtain the purity and composition of gold, jewelry, coins, and other pieces. Accurate and nondestructive, the countertop instrument uses x-ray fluorescence to determine precious metal content, karatage, and fineness in seconds so jewelers and others can see the purity of the gold, silver, platinum, palladium, and other precious metals in valuables. evidentscientific.com. With a new high purity testing center, cleaning specialist Ecoclean GmbH, Germany, is expanding its capacity for cleaning tests to suit high-tech components with extremely high purity requirements. The center features five cleaning systems for the technologies, media, and processes used in wet chemical component cleaning, such as ultrasound, injection flood washing, plasma cleaning, pulsed pressure cleaning, and ultrasound plus. ecoclean-group.net. BRIEFS A fatigue crack shown by a reconstructed morphology that adds an electron backscatter diffraction image from a cross section. Courtesy of National Institute for Materials Science. The patterned cuts in this elastic polymer, which houses the new sensor, enable a greater range of deformation without sacrificing sensitivity. Courtesy of NC State University/Shuang Wu.
A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 9 zigzag pattern, the material can withstand substantial deformation without reaching a breaking point. Second, when the cuts pull open, this forces the electrical signal to travel further, moving up and down the zigzag. “The sensor can be easily incorporated into existing wearable materials such as fabrics and athletic tapes, convenient for practical applications,” says researcher Yong Zhu. www.ncsu.edu. MEASURING THIN SKIN OF CALCIUM NUCLEI Studying the rare calcium-48 isotope, physicists determined how its 20 protons and 28 neutrons are distributed inside the nucleus. Measurements took place at the DOE’s Jefferson Lab, Newport News, Va. The researchers found that calcium’s protons and neutrons aren’t simply sprinkled throughout the nucleus—instead, they form a neutron-rich thin skin around a core of more-evenly distributed protons and neutrons. The researchers found that the calcium-48 neutron-rich skin is just 0.121 femtometers thick, a femtometer being just one billionth of a meter. This is thinner than many models predicted and is somewhat surprising in comparison with the thick neutron skin seen in lead. This is because existing theoretical models predicted that calcium-48 should have a thicker skin than it does, while these same models predicted a thinner neutron skin for lead than was measured. This new measurement is an exciting development for nuclear physics. It warrants further exploration of the thin skins of other heavy nuclei to determine why there’s a large discrepancy between nuclei of calcium, which has a medium mass, and more massive lead nuclei. Combining the data from these experiments will provide scientists with important constraints on future models of nuclear structure. The results also have implications for the neutron matter equation of state, which describes the structures of neutron stars and the dynamics of neutron-star mergers. energy.gov. In Jefferson Lab’s Experimental Hall A, scientists measured the distribution of protons and neutrons inside calcium-48 nuclei.
A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 1 0 MACHINE LEARNING | AI Engineers at the University of California, San Diego developed an AI algorithm to predict the structure and dynamic properties of any material almost instantly. Called M3GNet, the algorithm was used to develop matterverse.ai, a database of more than 31 million notyet-synthesized materials with properties predicted by machine learning algorithms. ucsd.edu. BRIEFS MATERIALS INFORMATICS TACKLES POLYMERS Scientists at the Research Organ- ization of Information and Systems (ROIS), Tokyo, recently created a comprehensive database of polymer properties. “Materials informatics (MI), a new branch of materials research that combines materials data with data science, is gaining traction,” says assistant professor Yoshihiro Hayashi. “MI applies machine learning to predict new materials with innovative properties and their fabrication methods from a vast design space. As such, data is the most important resource in MI.” Despite the need, Hayashi says efforts to create a comprehensive database of polymer properties to enable data-driven research have fallen short. “To construct a database of polymer properties by molecular simulations, we developed RadonPy,” Hayashi explains. “It’s the first open-source software that successfully automates polymer physical property calculations using simulations of classical molecular dynamics based on atomistic models, which account for the behaviors and characteristics of individual constituents.” The program takes an assigned polymer and runs calculations to equilibrate it in prescribed system parameters. Once it does, it can then calculate the polymer’s density, radius of gyration, refractive index, thermal conductivity, specific heat capacities at constant pressure and at constant volume, among other information. RadonPy produces and stores the data, which can then be accessed later. The researchers also implemented a machine learning technique called transfer learning to correct biases and variations between the simulated property values and experimental data. Scanning electron microscopy images depict novel nanostructures discovered by AI. Researchers describe the patterns as skew (left), alternating lines (center), and ladder (right). Scale bars are 200 nm. Plots visualizing the distribution of 21 classes of polymer backbones according to specific definitions. Courtesy of npj Computational Materials. The team also identified eight amorphous polymers with high conductivity. Now, the group is using RadonPy to create the world’s largest open database of polymer physics, with more than 100,000 different polymer species. In addition to ROIS, three universities and 19 companies are partnering to jointly develop other databases with RadonPy for a variety of applications in academia and industry. www.rois.ac.jp/en. NEW NANOSTRUCTURES COURTESY OF AI Scientists at the DOE’s Brookhaven National Laboratory, Upton, N.Y., successfully demonstrated an AI-driven technique that led to the discovery of three new nanostructures, including a first-ever nanoscale “ladder.” The structures were formed by self-assembly. Staff scientists now aim to build a library of self-assembled nanopattern types to broaden their applications. “The fact that we can now create a ladder structure, which no one has ever dreamed of before, is amazing,” says group leader Kevin Yager. The team is now applying their autonomous research method to other classes of materials. bnl.gov.
1 1 A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 EMERGING TECHNOLOGY 4D SCANNING FOR BETTER BATTERIES A team of multidisciplinary researchers from the University of Illinois Urbana-Champaign are combining a powerful new microscopy technique and data mining to design better rechargeable ion batteries. The combination strategy helps scientists visually pinpoint areas of chemical and physical alterations within batteries, enabling them tomap out altered domains at the nanoscale for the first time. According to the researchers, their 4D scanning transmission electron microscopy (STEM) method maps otherwise inaccessible variations of crystallinity and domain orientations inside materials. Previously, these types of microstructural heterogeneity transformations have only been studied in ceramics and metallurgy—until the initiation of this new work with batteries. The team compared its 4D-STEM observations to computational modeling to identify variations and study patterns in the nucleation, growth, and coalescence processes. “The impact of this research can go beyond the multivalent ion battery system studied here,” explains researcher Paul Braun. “The concept, principles, and the enabling characterization framework apply to electrodes in a variety of Li-ion and post-Li-ion batteries as well as other electrochemical systems including fuel cells, synaptic transistors, and electrochromics.” illinois.edu. EFFICIENT PHOTOVOLTAIC WINDOWS FOR SKYSCRAPERS Skyscrapers can be made more energy efficient through the addition of thermally efficient photovoltaic (PV) windows, according to an analysis by researchers at the National Renewable Energy Laboratory (NREL). Their findings outline building design rules that can yield a structure with net-zero or even net-positive energy consumption. Buildings account for more than a third of the world’s energy consumption and almost as much of global carbon dioxide emissions. But by combining PV with high thermal performance window technologies, new buildings can become a critical tool ENER Y TRE DS Marc-Antoni Racing, Stony Brook, N.Y., licensed several energy storage technologies developed at the DOE’s Oak Ridge National Laboratory, Tenn. The components enable fast-charging, energy-dense batteries for electric/hybrid vehicles and grid storage—plus achieve a key DOE goal of reducing vehicle battery charging time to under 15 minutes. ornl.gov. BRIEF Wenxiang Chen is the first author of a new study that applies imaging techniques common in ceramics. Graphical abstract depicting the energy transmission of thermally e icient PV windows. Courtesy of One Earth (2022). DOI: 10.1016/j.oneear.2022.10.014. in combatting climate change, the researchers noted. Modern office buildings stand out for their looming glass facades, a counterpoint to the days when they were constructed of concrete and single-pane windows. The Equitable Building in New York, for example, has a window-to-wall ratio of 25%. By comparison, the city’s Bank of America Tower opened in 2016, 101 years later, with a ratio of 71%. The researchers considered buildings with a window-to-wall ratio of 95%—dubbed “highly glazed”—for most of their analysis to clearly illustrate the impact glazing has on building energy performance. Improvements in glazing technologies such as triplepane windows helped improve the energy efficiency of buildings but so far have not been widely adopted. nrel.gov.
1 2 A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 NEXT GENERATION AIRCRAFT PROPULSION: A PRATT & WHITNEY APPROACH Sean Bradshaw Sustainable Propulsion, Pratt & Whitney East Hartford, Connecticut Aircraft engines that minimize fuel consumption and operate on sustainable aviation fuels are key to meeting the air transportation sector’s commitment to net zero CO2 emissions by 2050. S U S T A I N A B L E A V I A T I O N 1
1 3 A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 Fig. 2 — Pathways to sustainable propulsion. Fig. 1 — Environmental impacts of climate change. The aviation industry, which accounts for approximately 2.5% of global CO2 emissions, could potentially contribute a greater fraction of global CO2 emissions due to the estimated increase in customer demand for air travel by 2050. Current and nearterm aircraft that will remain in the skies for decades are designed around the combustion of kerosene. Conventional jet fuels contain fossil-based carbon that is released during the aircraft engine combustion process as well as through the extraction, refining, and delivery of these fuels. However, sustainable aviation fuels (SAF) offer great potential as near carbon-neutral sources of energy over their carbon life cycle, contributing to goals to achieve net zero carbon emissions by 2050. Widespread deployment and use of sustainable aviation fuels would enable the preservation of the capital asset values of legacy engine products as customers drive toward a net zero carbon future. In addition to SAF, improvements to aircraft and engine technology, operations, and infrastructure are required for the aviation industry to meet its sustainability goals because the supply of sustainable aviation fuel is less than 0.1% of global aviation fuel demand. As the aviation industry continues to develop technologies that reduce fuel consumption per unit of thrust by 1-1.5% per year, a broad, sustained effort to ensure aircraft engine compatibility with sustainable aviation fuels, as well as increased production and adoption of these renewable liquid hydrocarbons will be required to achieve net zero carbon emissions in aviation by 2050. SUSTAINABLE AVIATION CHALLENGE Climate change impacts people and economies. The greater frequency and severity of inclement weather conditions caused by human activity since the pre-industrial age has increased the risk to human health, property, and global economic growth. As a result, mitigating the impacts of anthropogenic climate change to meet the goals of the United Nations Paris Agreement signed in 2016 is one of the most urgent challenges of our time. The shared goal of the Paris Agreement was to limit global warming to 1.5°C above pre-industrial levels. The aviation industry is one of six hard-to-abate sectors, along with cement, steel, plastics, trucking, and shipping. Together, these hard-to-abate sectors emit 30% of global annual CO2 emissions. As easier-to-abate sectors, such as automotive and power generation, decarbonize, and as global demand for air travel increases, the aviation industry’s contribution to global CO2 may rise substantially by 2050. The Air Transportation Action Group (ATAG) has produced a report called Waypoint 2050 that outlines the key technologies and strategies that would enable a net zero CO2 air transportation sector by 2050. The unmitigated growth of the aviation sector would more than double CO2 emissions by 2050 relative to 2022[1]. Advanced airframe and propulsion system technologies would enable a 30-35% reduction in CO2 emissions relative to the baseline unmitigated growth scenario. Strategies that improve aircraft operational efficiency, such as trajectory optimization, may yield an additional 5-10% reduction in CO2 emissions relative to the unmitigated growth scenario. Aggressive aircraft technology development and airline operational efficiency measures may only yield up to 45% reduction in CO2 emissions relative to the unmitigated growth scenario. Low carbon intensity fuels, such as sustainable aviation fuels and hydrogen, would be required at commercial scale to reduce aviation CO2 emissions by another 50-55%. The remaining gaps to achieve the net zero CO2 emissions goal by 2050 would be addressed through market-based measures such as CORSIA (Carbon Offsetting and Reduction Scheme for International Aviation). PRATT & WHITNEY’S APPROACH TO SUSTAINABLE PROPULSION Pratt & Whitney (P&W) joined an industry-wide commitment to achieve net zero transport carbon emissions by 2050 in support of the Paris Agreement, and developed a technology strategy to support our customers’ commitments toward this goal. Pratt & Whitney’s approach to sustainable propulsion consists of: 1) continuing to develop the advanced gas turbine propulsion technologies that improve efficiency,
1 4 A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 2) ensuring that P&W engines are fully compatible with approved sustainable aviation fuels, 3) developing advanced technologies for hybrid-electric propulsion, and 4) developing advanced technologies for hydrogen propulsion (Fig. 2). Geared Turbofans. Gas turbine propulsion systems are reliable, efficient, and fuel-flexible generators of thrust power. Currently, aircraft that operate Pratt & Whitney’s GTF (Geared Turbofan) engines yield up to 16% lower thrust specific fuel consumption and CO2 emissions relative to legacy turbofan engines such as the V2500. Furthermore, GTF engine operations generate 50% fewer nitrous oxide (NOx) emissions and 75% lower noise footprint around airport communities than legacy engines. As a result, GTF engines provide reliable thrust power while reducing the impact to the climate, local air quality, and airport communities. The Pratt & Whitney GTF Advantage engine, which is scheduled for certification in 2023, will deliver increased thrust, matured reliability, 1% lower specific fuel consumption relative to the GTF base engine, and 100% SAF compatible combustion technology (see Fig. 3). Pratt & Whitney will continue to invest in advanced gas turbine technologies, such as high temperature materials, advanced cooling and sealing technologies, advanced turbomachinery, and advanced combustion systems that increase fuel efficiency and lower greenhouse gas emissions on future aircraft. Sustainable Aviation Fuels. A sustainable aviation fuel (SAF) is a liquid hydrocarbon that is made from renewable energy sources and meets the technical and certification requirements for use in commercial aircraft[2,3]. Essentially, the carbon emitted during the flight is offset by carbon sequestered during the SAF feedstock biological and manufacturing processes. However, these processes take energy and are not completely carbon-neutral today. Burning SAF could yield up to an 80% reduction in life cycle carbon emissions relative to fossil-derived jet fuels[5]. The feedstocks for sustainable aviation fuels include animal matter (cooking oil, fats, greases), municipal solidwaste, and plant matter (algae, jatropha, camelina, forestry waste). In the future, electricity generated from renewable energy sources combined with CO2 that is captured from industrial processes or from the ambient air could be used to make SAF as well. Today, there are seven ASTM-approved bio-derived sustainable aviation fuel blends that have been certified for commercial engine use. Five of these SAF blends have been approved up to a 50% blending limit with conventional jet fuel[6]. Additional technology pathways for sustainable aviation fuel blends are under evaluation by ASTM International. The currently approved blended SAFs contain properties that meet the conventional jet fuel specifications. As a result, these approved SAF blends are interchangeable with conventional jet fuel, do not harm engine performance or operability, would require no change to aircraft technology or design, nor any change to airport infrastructure. Moreover, aircraft that operate on SAF blends up to 50% may yield up to 40% lower net CO2 emissions relative to aircraft that operate on fossil-derived jet fuels. In the future, sustainable aviation fuel blends up to 100% may be approved for use by ASTM International. P&W has been testing engines on 100% SAF for over 16 years to ensure maximum readiness. P&W successfully conducted operability testing on the PW1100G-JM with 100% hydro- processed esters and fatty acids synthetic paraffinic kerosene (HEFA-SPK) inMarch 2022. This testing was followed with successful on-wing ground and flight demonstrations of the PW1900G operating on 100% HEFA-SPK in June 2022. These tests showed that there was no difference in GTF engine operation with 100% HEFA-SPK and with 100% conventional jet fuel. Moreover, Pratt &Whitney Canada, a business unit of Pratt & Whitney, successfully completed a two-hour flight test of the two PW127 turboprop engines with 100% HEFA-SPK on a Braathen Regional Airlines ATR 72-600 aircraft in July 2022. Hybrid-Electric Propulsion. Electrification will play a key role in enabling smarter and cleaner aircraft engines. P&W and Collins Aerospace are strongly positioned to lead the development of integrated hybrid-electric propulsion technologies. The Scalable Turboelectric Powertrain Technology (STEP-Tech) Demonstrator, a P&W and Collins Aerospace technology demonstrator program, was established to mature scalable and adaptable technologies for advanced air mobility, regional aircraft, and single-aisle air- craft applications. These activities are initially aimed at 100 – 500 KW-class propulsion systems to address the emerging field of advanced air mobility. The scalable and modular technology solutions in the STEP-Tech program will also support the accelerated development of hybrid-electric propulsion systems for regional and single-aisle aircraft applications. Moreover, P&W Canada is collaborating with De Havilland Canada, Collins Aerospace, H55 S.A., Ricardo PLC, National Research Council of Fig. 3 — GTF Advantage engine. Fig. 4 — 100% SAF readiness with engine testing: (a) Supporting up to 50% SAF operational use today; (b) ground and flight testing up to 100% SAF; and (c) ensure future engines ready for 100% SAF standard. (a) (b) (c)
1 5 A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 Canada, Innovative Vehicle Institute, and the Governments of Canada and Quebec on a Regional Hybrid Electric Flight Demonstrator based on the De Havilland Canada Dash 8-100 to mature hybrid-electric technologies. This engine demonstration will feature advanced electric and thermal engine technologies may yield up to 30% improvement in fuel efficiency relative to thebaseline thermal engine. Aground demonstration of these advanced technologies was successfully executed in 2022. A flight demonstration for these hybrid-electric technologies is scheduled for 2024. The learning from these demon- strations will be applied to hybrid- electric engines for future single-aisle applications. These advanced propulsion systems, which would include foundational GTF engine technologies, hybrid-electric engine technologies, a 100% SAF-compatible, advanced low emissions combustion system, and exhaust waste heat recovery technologies, would yield a step change in mission energy reduction and environmental performance. Pratt &Whitney, MTU Aero Engines AG, GKN Aerospace, and Collins Aerospace announced the formation of a consortium supported by the EU Clean Aviation Undertaking. The project under this consortium, called Sustainable Water-Injecting Turbofan Comprising Hybrid Electrics (SWITCH), is developing advanced technologies for hybrid- electric engines that enable up to a 25% improvement in fuel efficiency relative to today’s state-of-the-art aircraft engines for short- and medium-range aircraft while substantially reducing greenhouse gas emissions. These advanced technologies include hybrid-electric, advanced SAF-compatible combustors, and exhaust waste heat recovery technologies. These advanced propulsion technologies will also be evaluated for future use with the hydrogen energy carrier. Hydrogen Propulsion. Hydrogen- powered aircraft may enable the aviation industry to achieve net zero CO2 emissions by 2050. Pratt & Whitney is developing an advanced hydrogen propulsion concept called the Hydrogen Steam Injected and Intercooled Turbine Engine (HySIITE). Pratt & Whitney is evaluating the requirements of the overall propulsion system as well as that of the advanced, low NOx combustor and advanced heat exchanger component technologies under a twoyear United States Department of Energy (DOE) Office of Advanced Research Projects Agency for Energy (ARPA-E) contract. HySIITE leverages cryogenic liquid hydrogen as a heat sink to augment thermodynamic efficiency by up to 35% relative to current best-in-class commercial engines while generating thrust with zero CO2 emissions. This engine features a steam-injected combustion system to deliver low NOx emissions. Furthermore, an evaporator transferswasteheat to the cryogenically cooled liquid hydrogen to increase its enthalpy prior to injection into the combustor. In addition, a condenser capture captures and converts water vapor to support steam-injection into the combustor, intercooling of the compression system, and turbine cooling. Fig. 5 — Hybrid electric propulsion. Fig. 6 — Advanced hydrogen propulsion system. Hydrogen that is manufactured from renewable energy sources would be needed to decarbonize global aviation. However, only 0.1% of hydrogen is produced from renewable energy sources today[1]. Significant investment in the global infrastructure for commercial scale green hydrogen production is needed to achieve net zero carbon emissions in aviation by 2050. Pratt & Whitney will continue to mature the suite of advanced technologies required for hydrogen propulsion as these investments are made. CONTRAILS Condensation trails, also known as contrails, are ice clouds that form due to the mixing between an aircraft engine exhaust plumes and ambient air[10]. Contrails can create persistent cirrus clouds that may scatter shortwave solar radiation, resulting in a cooling effect, and reflect terrestrial long wave radiation, which yields a warming effect. Approximately, 5-10% of flights make 80-90% of contrails. However, the net radiative forcing from persistent contrails yields a warming effect that may exceed that of CO2 emissions[10]. The impact of non-CO 2 emissions, including contrail effects, increase the aviation industry’s environmental footprint to approximately 3.5% of global anthropogenic climate impact[1]. The probability of occurrence of a contrail is a function of the ambient air properties, aviation fuel properties, and engine efficiency. The contrail formation process is enabled by the presence of particulates around which super-saturated water vapor freezes and forms ice crystals. Most of these particulates are produced by the aircraft engine combustion process and emitted in the exhaust plume. The remaining particulates are airborne aerosols that are always present in the atmosphere. Sustainable aviation fuels that contain lower levels of sulfur and aromatic hydrocarbons may generate fewer particulate emissions in the combustion process, yielding fewer ice crystals,
1 6 A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 optically thinner contrails, and less global warming due to aviation. Hydrogen combustion yields zero sulfate and non-volatile particulate emissions, but 2.6 times more water vapor. Increased humidity in the exhaust combinedwith the presence of airborne aerosols may increase the probability of occurrence of contrails. However, the absence of sulfates and non-volatile particulates may decrease the radiative forcing of persistent contrails and aviation induced contrail cirrus clouds. Additional research is needed to quantify the impact of alternative fuel sulfur content, aromatic hydrocarbon concentration, carbon-to-hydrogen ratio, and airborne aerosol concentration on the contrail formation process and associated radiative forcing effects. This re- search learning would be used to assess the overall environmental impact of suite of sustainable propulsion technologies and alternative fuels as well as influence the technological and operational strategies for detecting, avoiding, and mitigating contrails and their environmental effects. SUMMARY Climate change impacts people and economies. As a result, mitigating the impacts of anthropogenic climate change to meet the goals of the United Nations Paris Agreement signed in 2016 is one of the most urgent challenges of our time. The shared goal of the Paris Agreement was to limit global warming to 1.5°C above pre-industrial levels. The aviation industry, which accounts for approximately 2.5% of global CO2 emissions, could potentially contribute a greater share of global CO2 emissions by 2050 due to the estimated increase in customer demand for air travel. Pratt & Whitney has affirmed the ATAG agreement to help achieve net zero air transport carbon emissions by 2050. The International Air Transport Association(IATA) approvedaresolution for the global aviation industry to achieve net zero CO2 emissions by 2050. Pratt & Whitney’s approach consists of developing technologies, such as high efficiency, low-emissions aircraft engines compatible with cleaner fuels, such as ASTM-approved, drop-in compatible sustainable aviation fuels and green hydrogen. Non-CO2 emissions effects, including contrail effects, further increase the aviation industry’s overall environmental impact. Specifically, contrail effects may rival that of CO2 as contributors to global warming due to commercial aviation traffic, yet there is significant uncertainty in these assessments. Further study is required to fully understand the impact of alternate fuels on the contrail formation process and effective radiative forcing of contrail cirrus clouds. The learning from these contrail studies would provide the aviation industry with valuable data to fully evaluate the impact of proposed sustainable propulsion technologies and alternative fuels on the environment. ~AM&P Note Pratt & Whitney GTF and Pratt & Whitney GTF Advantage are trademarks of Pratt & Whitney. Formore information: Sean Bradshaw, senior fellow, sustainable propulsion, Pratt & Whitney, 400 Main St., East Hartford, CT 06118, 860.294.6392, sean.bradshaw@prattwhitney.com. References 1. Waypoint 2050. ATAG. https:// aviationbenefits.org/media/167417/ w2050_v2021_27sept_full.pdf. 2. Net Zero Carbon Emissions by 2050, IATA, October 4, 2021. 3. Aviationbenefits.Org, https://aviationbenefits.org/media/166152/beginners-guide-to-saf_web.pdf. 4. Total fuel consumption of commercial airlines worldwide between 2005 and 2019, IATA / ICAO, https://www. statista.com/statistics/655057/fue l-consumption-of-airlines-worldwide/. 5. M.D. Staples, et al., Aviation CO2 Emissions Reductions from the Use of Alternative Jet Fuels, Energy Policy, Vol. 114, p 342-354, 2018. 6. Commercial Alternative Aviation Fuels Initiative (CAAFI), https://www. caafi.org/focus_areas/fuel_qualification.html. 7. FAA Response to Research, Engineering, and Development Advis- ory Committee Recommendations for the Fiscal Year 2023 Research and Development Portfolio, https:// www.faa.gov/about/office_org/head- quarters_offices/ang/redac/media/responses/RecommendationsResponse- FY2023.pdf. 8. Sustainable Aviation Fuel: Review of Technical Pathways, Office of Energy Efficiency & Renewable Energy, U.S. Department of Energy, p 9-10, September 9, 2020, https://www.energy.gov/eere/bioenergy/downloads/ sustainable-aviation-fuel-review-technical-pathways-report. 9. D.S. Lee, et al., The Contribution of Global Aviation to Anthropogenic Climate Forcing for 2000 to 2018, Atmospheric Environment, Vol. 244, 117834, January 2021. 10. Cleaner Burning Aviation Fuels Can Reduce Contrail Cloudiness, Article number: 114 (2021), Communications Earth & Environment, https://www.nature.com/articles/s43247-021-00174-y. 11. STEP-Tech Demonstrator, Pratt & Whitney Press Release, December 20, 2022, https://newsroom.prattwhitney. com/2022-12-20-Raytheon-TechnologiesCompletes-First-Engine-Run-of-RegionalHybrid-Electric-Flight-Demonstrator. 12. SWITCH, Pratt & Whitney Press Release, November 29, 2022, https:// newsroom.prattwhitney.com/2022-1129-Clean-Aviation-SWITCH-Project-toAdvance-Hybrid-Electric-and-WaterEnhanced-Turbofan-Technologies.
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