18 24 29 P. 14 NOVEMBER/DECEMBER 2023 | VOL 181 | NO 8 Beamline Characterization at ORNL’s Spallation Neutron Source 3D Microscopy of Phosphate Minerals Neodymium Magnet Inventors Earn Honda Prize REVEALING GRAIN BOUNDARIES IN ALUMINUM ALLOYS TESTING/CHARACTERIZATION
18 24 29 P. 14 NOVEMBER/DECEMBER 2023 | VOL 181 | NO 8 Beamline Characterization at ORNL’s Spallation Neutron Source 3D Microscopy of Phosphate Minerals Neodymium Magnet Inventors Earn Honda Prize REVEALING GRAIN BOUNDARIES IN ALUMINUM ALLOYS TESTING/CHARACTERIZATION
2024 INTERNATIONAL MATERIALS, APPLICATIONS & TECHNOLOGIES HUNTINGTON CONVENTION CENTER | SEPTEMBER 30–OCTOBER 3, 2024 | CLEVELAND, OHIO MATERIALS FOR ENERGY STORAGE IMAT, ASM International’s annual meeting, will focus on membership and materials community needs, offering an industry-oriented conference and exposition. IMAT will target a broad range of materials, processes, and their applications, with an emphasis on advanced materials and manufacturing technologies. Traditional topics of interest will be explored, including metals, ceramics, composites, coatings, alloy development, microstructure/process/properties relationships, phase equilibria, mechanical behavior, joining, corrosion, and failure analysis. Emerging topics, instrumental in advancing materials development and cutting-edge technologies, will be covered. Technologies such as advanced manufacturing, including additive, Industry 4.0 and digitization of the materials industry, biomedical/multifunctional materials, power and transportation industries, materials for energy, renewable and sustainable materials and processes, as well as materials to enable automation and robotics will be covered. Students will have the opportunity to showcase their research and connect with future materials scientists through various events and competitions. CALL FOR ABSTRACTS ORGANIZED BY: Shape Memory & Superelastic Technologies Abstracts are solicited in the following areas: • Additive Manufacturing • Archaeometallurgy and Ancient Metalworking • Characterization of Materials and Microstructure through Metallography, Image Analysis, and Mechanical Testing: Fundamental and Applied Studies • Corrosion and Environmental Degradation • Emerging Technologies • Failure Analysis • Functional Materials and Structures: Solving Barriers to Adoption • Joining of Advanced and Specialty Materials (JASM XXII) • Light Metal Technology • Materials 4.0: Materials Information in the Product Life Cycle • Materials Behavior & Characterization • Materials for Energy & Utilities • Medical / Biomaterials: Delivering Patient Value • Materials & Processes for Automation • Metals, Ceramics, and Composite Materials: Raw Materials, Processing, Manufacturing Methods, Applications, and Environmental Effects • Perspectives for Emerging Professionals • Processing and Applications • PSDK XV: Phase Stability and Diffusion Kinetics • Sustainable Materials & Processes ABSTRACT SUBMISSION DEADLINE: FEBRUARY 14, 2024 imatevent.org ORGANIZING PARTNER: CO-LOCATED WITH: IFHTSE World Congress
38 ASM NEWS The latest news about ASM members, chapters, events, awards, conferences, affiliates, and other Society activities. A TWO-STEP ETCHANT TO REVEAL GRAIN BOUNDARIES IN MULTIPLE ALUMINUM ALLOYS Wayne Papageorge, Elvin Beach, and Greg Janas This entry won the prestigious DuBose-Crouse Award for unique, unusual, and new techniques in microscopy at the 2022 International Metallographic Contest. 14 ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 2 Bright-field optical micrographs of a nominally 3 mm thick sheet of AA2024-T3. Courtesy of Papageorge et al. On the Cover: 44 HIGHLIGHTS FROM IMAT 2023 This photo gallery features some of the awards, meetings, and fun had at IMAT 2023 in Detroit. 29 INVENTOR SPOTLIGHT 2023 HONDA PRIZE HONORS NEODYMIUM MAGNET INVENTORS With this year’s prestigious Honda Prize, the Honda Foundation is recognizing John J. Croat, FASM, and Masato Sagawa for simultaneously inventing the neodymium magnet.
4 Editorial 5 Research Tracks 10 Machine Learning 6 Metals/Polymers/Ceramics 8 Testing/Characterization 11 Process Technology 12 Emerging Technology 13 Sustainability 51 Editorial Preview 51 Special Advertising Section 51 Advertisers Index 52 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. 8, NOVEMBER/DECEMBER 2023. Copyright © 2023 by ASM International®. All rights reserved. Distributed at no charge to ASM members 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 Kodi Collective, Lebanon Junction, Ky. 18 THE VENUS IMAGING BEAMLINE AT THE ORNL SPALLATION NEUTRON SOURCE Hassina Z. Bilheux, R. Aaron Hanks, Jean-Christophe Bilheux, Harley Skorpenske, Mary-Ellen Donnelly, Jamie Molaison, and Amy Byrd With the VENUS beamline, hyperspectral neutron radiography measures crystalline properties and elemental/isotopic content in materials. 24 ON THE DIVERSITY OF PHOSPHATE MINERALS FOR POTENTIAL APPLICATIONS Jin Zhang, Shri Patel, and Surojit Gupta An exploration of five non-apatite phosphate minerals using 3D optical profilometry reveals their suitability for new uses in energy storage and conversion as well as medical applications. 32 ADVANCED MANUFACTURING PANEL AT IMAT 2023 Representatives from each of ASM’s affiliate societies join a panel discussion on the impact of new materials and manufacturing technologies in their industries. FEATURES NOVEMBER/DECEMBER 2023 | VOL 181 | NO 8 ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 3 18 32 34 24 34 UTILIZING FTIR SPECTROSCOPY FOR PLASTICS FAILURE ANALYSIS Jeffrey A. Jansen This article explores one of the most commonly used analytical techniques in plastic component failure analysis—Fourier transform infrared (FTIR) spectroscopy— along with a case study to demonstrate its use.
4 ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 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 John Shingledecker, Chair, EPRI Beth Armstrong, Vice Chair, Oak Ridge National Lab Adam Farrow, Past Chair, Los Alamos National Lab Rajan Bhambroo, Tenneco Inc. Daniel Grice, Materials Evaluation & Engineering Surojit Gupta, University of North Dakota 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 ASM BOARD OF TRUSTEES Pradeep Goyal, President and Chair Navin Manjooran, Senior Vice President Elizabeth Ho man, Vice President David B. Williams, Immediate Past President Lawrence Somrack, Treasurer Amber Black Ann Bolcavage Pierpaolo Carlone Hanchen Huang André McDonald Christopher J. Misorski U. Kamachi Mudali James E. Saal Dehua Yang Sandra W. Robert, Executive Director STUDENT BOARD MEMBERS Kingsley Amatanweze, Karthikeyan Hariharan, Denise Torres 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 from articles 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. FLUSH WITH OPPORTUNITY Technological advancements don’t come easy. But breakthroughs do tend to build upon each other. In the early 1980s, two men on different continents independently yet simultaneously developed a rare earth magnet from neodymium. Their unique story is chronicled in this issue and recently earned them the Honda Prize, 40 years after their invention. Building off that early research, next-gen magnets for use in electric vehicles, wind turbines, and computers are now being developed by Niron Magnetics, with less mining, extraction, and manufacturing costs than what is required for rare earth magnets. In her keynote at the recent IMAT 2023 event in Detroit, Evelyn Wang of the Advanced Research Projects Agency-Energy (ARPA-E) cited Niron’s clean earth magnet as one example of a technology the agency currently supports. Her talk on “How Materials Innovations Can Enable Transformative Energy Solutions” discussed the goal of getting to net zero emissions by 2050. According to Wang, with challenges come opportunities. There are mountains of opportunities for transforming the energy landscape. Her strategy is to look for technological white spaces—areas with little development that provide the greatest opportunities for expansion. Seeing challenges as opportunities was also the mantra of Dave Furrer, FASM, as he moderated IMAT’s Advanced Manufacturing panel session, which is summarized in this issue. The multidisciplinary Affiliate Society panel offered a wide range of perspectives as speakers represented Blue Origin, IBM, NASA, and several universities. Each panelist shared insights on the impact of new materials and manufacturing technologies in their respective fields. NASA also provided a keynote speaker this year. Bryan McEnerney discussed “The Challenges of Insertion of Advanced Materials & Processes for Spaceflight.” For space missions, just because a material has been tested does not mean the process is ready. There needs to be a complementary material and manufacturing readiness level. A material does not exist in a vacuum; it must integrate into subsystems. As if developing parts for space isn’t difficult enough. In his Edward DeMille Campbell lecture, Rusty Gray, FASM, talked about the challenges of developing alloys for new processes like additive manufacturing (AM) and said we must be “process aware.” Process and structure are closely linked to properties and performance. The AM process creates different properties and machine uniformity can be challenging. America Makes, Lockheed Martin, and Boeing among others are all working on qualification and certification of AM parts. It’s one step toward building a roadmap for AM. How do we get to the next technological breakthroughs? The combined wisdom of the keynote and special lecturers at this year’s IMAT indicates that we need partnerships, collaborations, multidisciplinary discussions, readiness guidelines, qualification standards, and roadmap committees. We need to be inquisitive and work in the “white spaces.” But mostly we need to see challenges in a new way. In their view, the world—and space—appear to be flush with opportunities. joanne.miller@asminternational.org ARPA-E’s Evelyn Wang gives keynote at IMAT.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 5 MEET MOLYBDENENE: GRAPHENE’S METALLIC COUSIN Scientists at Forschungszentrum Jülich, Germany, along with colleagues from the Indian Institute of Technology in Patna and the Australian University of Newcastle, created a new 2D material that exhibits a metallic character. Named molybdenene, it consists of just one atomic layer of molybdenum atoms. In addition to graphene, other 2D relatives such as phosphorene and germanene have been introduced in recent years. All have impressive properties, but molybdenene features some unusual benefits. “Many 2D materials are sensitive to heat, but molybdenene is not. Moreover, this is the first metallic 2D material where freestanding layers could be prepared,” says Prof. Ilia Valov of Forschungszentrum Jülich. The researchers created the new 2D material using a microwave, in which they heated a mixture of molybdenum sulfide and graphene to incandescence at a temperature of around 3000°C. In a reaction driven by the microwave electric field, finely branched hair structures called whiskers were formed, in which the tapered molybdenum layers RESEARCH TRACKS can be found. The scientists have already observed a range of useful properties and expect that the material has further exotic electronic properties, similar to graphene, due to its 2D structure. Because of its metallic character, it also has freely moving electrons. These accumulate on the two sides of the molybdenene, which makes the material an interesting candidate as a catalyst as well. The international team has already developed a practical application for molybdenene. Due to its stability and excellent electrical and thermal conductivity, it is well suited for use as a measuring tip for atomic force microscopy and surface-enhanced Raman spectroscopy. www.fz-juelich.de. BETTER BATTERIES VIA COMPUTER VISION Researchers from the DOE’s SLAC National Accelerator Laboratory, Stanford University, the Massachusetts Institute of Technology, and Toyota Lithium ions flowing in and out of battery electrode nanoparticles during battery cycling. The false colors show the charge status of each particle and reveal how uneven the process within a single particle can be. Courtesy of Cube3D. Research Institute are using machine learning to re-analyze x-ray movies of lithium ions flowing in and out of battery electrode nanoparticles during battery cycling. More specifically, the team is using a type of machine learning called computer vision to study each pixel of those movies in order to discover physical and chemical details of battery cycling that could not be seen before. The new method suggests a way to make the billions of lithium iron phosphate (LFP) nanoparticles in one type of lithium-ion battery electrode store and release charge more efficiently, say scientists. In this latest study, professors William Chueh of Stanford and Martin Bazant of MIT used computer vision to mine more detailed information from 62 of the nanoscale x-ray movies they made in 2016 of LFP particles charging or discharging. Each still image from those movies contains roughly 490 pixels, giving them roughly 180,000 pixels of information to work with. The most significant finding of the research—that variations in the thickness of an LFP particle’s carbon coating directly control the rate at which lithium ions flow in and out— could lead to more efficient battery charging and discharging. www6.slac. stanford.edu. High-resolution electron microscope image of molybdenene. Courtesy of Nature Nanotechnology.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 6 METALS | POLYMERS | CERAMICS has eliminated the need for harmful chemicals. The microbe selectively adsorbs—or clings—to these rare earth elements, making it an ideal candidate to carry out an environmentally friendly purification procedure. Generally, S. oneidensis feeds on f-block elements residing in the sixth row of the periodic table, known as the lanthanides. Characterizing the S. oneidensis’s genome allows scientists to tweak its preference for processing the other rare earth elements. The researchers screened 3373 parts of the S. oneidensis genome and found 242 genes that influence it. The mutant genes found in the bacteria by the scientists can reduce the length of that rare earth element purification process by almost one-third— compared with the wild variety of S. oneidensis—and offers a roadmap for honing this green method. “Our work points to key genes that control membrane composition that are traditionally responsible for cell adhesion and biofilm formation in rare earth element biosorption,” says lead researcher Sean Medin. He says their work has the potential to make processing rare earths cleaner and scalable. “Currently all the purification of rare earth elements is done abroad, due to stringent environmental regulations and high infrastructure costs of building a separations plant,” he continues. IMPROVING WEARABLE ELECTRONICS A new self-healing, super flexible, and highly conductive material suitable for stretchable electronic circuitry was created by researchers at the National University of Singapore. This breakthrough could significantly improve the performance of wearable technologies, soft robotics, smart devices, and more. The newly engineered material, called the Bilayer Liquid-Solid Conductor (BiLiSC), can stretch up to a remarkable 22 times its original length without sustaining a significant drop in its electrical conductivity. Achieving this mechano-electrical property enhances the comfort and effectiveness of the human-device interface and opens up a wide array of opportunities for its use in healthcare wearables and other applications. According to the researchers, the liquid metal circuitry using BiLiSC allows these devices to withstand significant deformation and even self-heal to ensure electronic and functional integrity. nus.edu.sg. MICROBES REFINE RARE EARTH ELEMENTS To date, rare earth element purification processes have relied heavily on organic solvents and harsh chemicals. Now, scientists from Cornell University, Ithaca, N.Y., recently characterized the genome of Shewanella oneidensis—a metal-loving bacteria with an affinity for rare earth elements— to replace harsh chemical processing with a benign practice called biosorption. Using microbes to selectively adsorb and purify rare earth elements, the research team Prof Lim Chwee Teck (le ) and Dr. Chen Shuwen have developed a novel liquid-metal material suitable for stretchable electronics. Scientists at Columbia University, the University of Connecticut, and the DOE’s Brookhaven National Laboratory fabricated a pure form of glass and coated specialized pieces of DNA with it. The result is a material that is four times stronger than steel with a density roughly five times lower, making it both incredibly strong and lightweight. bnl.gov. BRIEF These Petri dishes containing microbes will eventually be used to dissolve the mineral monazite for extracting rare earth elements.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 7 “Our process potentially would be significantly less land- and capital- intensive to build, as our separations could be done with repeated enrichment through columns full of immobilized bacteria instead of mixer-settler plants that are miles long.” While the technology is still in development, the researchers are optimistic about potential impact. The method could help develop a stable U.S. supply of rare earth elements for technology and defense applications, according to the scientists. cornell.edu. DISCOVERY OF PHOTONIC CRYSTALS ON ANCIENT ROMAN GLASS Tiny pieces of glass are being uncovered from construction sites and archaeological digs that once were glass vessels in ancient Rome. On their surface is a mosaic of iridescent colors of blue, green and orange, with some displaying shimmering gold- colored mirrors. The beautiful structures formed over time, likely as a process of corrosion and reconstruction. For Fiorenzo Omenetto and Giulia Guidetti, professors of engineering at the Tufts University Silklab, what’s fascinating is how the molecules in the glass rearranged and recombined with minerals over thousands of years to form photonic crystals—ordered arrangements of atoms that filter and reflect light in very specific ways. Photonic crystals have many applications in modern technology. They can be used to create waveguides, optical switches, and other devices for very fast optical communications in computers. They are also used in filters, lasers, mirrors, and anti-reflection devices. Through elemental analysis, Omenetto and Guidetti could see that the patina possessed a hierarchical structure made up of highly regular, micrometer-thick silica layers of alternating high and low density which resembled Bragg stacks. The vertical stacking of tens of Bragg stacks resulted in the golden mirror appearance of the patina. “The crystals grown on the surface of the glass are also a reflection of the changes in conditions that occurred in the ground as the city evolved—a record of its environmental history,” says Guidetti. tufts.edu. Microscopic view of photonic crystals on the surface of ancient Roman glass. Courtesy of Giulia Guidetti. Are you maximizing your ASM membership? Expand your knowledge and apply your ASM International member-only discounts to a variety of professional development resources: • Reference Materials • ASM Handbooks Online • Technical Journals • Continuing Education Courses Learn more about your membership benefits by visiting: asminternational.org/membership 154 Hobart Street, Hackensack, NJ 07601 USA +1.201.343.8983 • mainmasterbond.com www.masterbond.com key benefits of nanosilica filled epoxy EP30NS use a nanoreinforced EPOXY Optically clear | Refractive index: 1.56 NASA low outgassing | ASTM E595 Dimensionally stable | Hardness: 80-90 Shore D Abrasion resistant | ASTM D466-14
8 ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 designing and analyzing polymers. Capable of mixing materials, analyzing their properties, and maintaining a digital database, the system will accelerate ongoing and future efforts to develop energy-efficient manufacturing methods and produce sustainable plastics. The three-year installation pro- cess is set to begin in November 2023. The system consists of four large modules, and the process begins when researchers load a selection of starter materials into the first module. These ingredients can be solid, liquid, or a viscous consistency that exists between the two, and they are stored individually inside the module. From these materials, investigators can order project-specific solutions, which the machine dispenses into test tubes and transfers to the mixers via robotic arm. With the test tubes filled and mixed, the samples advance to the subsequent modules for characterization to identify their properties. One module will gauge thermal properties, another rheo- logical properties—and yet another is fully customizable for project-specific characterizations like optical imaging. Additional modules may be added in the future as research interests ebb and flow. More than just a physical task- master, the system will also include sophisticated software to match the details of each solution to an accurate description of its properties, making results more reliable and experiments more repeatable. Researchers aided by TESTING | CHARACTERIZATION BALL MILLING BENEFITS BATTERY MATERIALS Advances in next generation ma- terials for lithium-ion batteries have been getting an extra boost from the use of ball milling. Now, scientists at the University of Birmingham discovered that routine ball milling can cause high pressure effects on battery materials in just a matter of minutes, providing a vital additional variable in the process of synthesizing battery materials. The process is fairly simple and consists of milling powder compounds with small balls that mix and make the particles smaller, creating high-capacity electrode materials and leading to better performing batteries. The researchers found that dy- namic impacts from colliding milling balls with battery materials create a pressure effect which plays an important role in causing the changes. They also discovered that applying heat would cause some compounds to return to their pre-milled state, signifying that an additional variable was at play in the original synthesis—pressure being key. According to the researchers, their discovery provides the opportunity to develop cheaper, more energy efficient processes for battery manufacturers, and also to explore avenues for new materials. www.birmingham.ac.uk. AUTOMATED POLYMER RESEARCH INSTRUMENT With a $3.6 million major research instrumentation grant from the National Science Foundation, the University of Illinois at Urbana-Champaign will acquire a fully automated system for Triangular holes make this material more likely to crack from left to right. Courtesy of N.R. Brodnik et al./Phys. Rev. Lett. Camtek, Israel, will acquire FormFactor Inc.’s FRT metrology business for $100 million in cash. FRT, Germany, is a supplier of high-precision metrology equipment for the advanced packaging and silicon carbide markets, while Camtek provides inspection and 3D metrology instruments to the semiconductor industry. camtek.com. Different manufacturing techniques could help to create better batteries. Software developer Molydyn will use chemical simulation to test new composite materials in collaboration with the University of Sheffield Advanced Manufacturing Research Centre (AMRC) and Bitrez to make the testing process more sustainable. The U.K.-based project aims to use molecular modeling to develop a viscosity modeling capability for Molydyn’s Atlas simulation platform to help design composite materials with reduced environmental impact. molydyn.com. BRIEFS Development engineer for composites at AMRC tests for material viscosity.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 9 automation can create at least 50 times the number of samples than would be feasible with human hands alone. The instrument can also run 24 hours a day for long periods of time with minimal human intervention. Once the data is recorded, researchers can use artificial intelligence or machine learning methods to pan the data for parcels of insight. The scientists say the new system will allow them to quickly and efficiently navigate large, variable spaces within additive manufacturing to develop optimal materials. illinois.edu. COMBINATION TESTING OF PEROVSKITE SOLAR CELLS According to researchers at the U.S. Department of Energy’s (DOE’s) National Renewable Energy Laboratory (NREL), Golden, Colo., perovskite solar cells should be subjected to a combination of stress tests simultaneously to best predict how they will function outdoors. Solar cells must endure a set of harsh conditions—often with variable combinations of changing stress factors—to judge their stability, but most researchers conduct these tests indoors with a few fixed stressing conditions. The NREL-led research team put perovskite solar cells through a battery of tests. During the test for operational stability, the cells retained more than 93% of their maximum efficiency after about 5030 hours of continuous operation. The cells were subjected to thermal cycling, with temperatures repeatedly fluctuating between -40°C and 85°C. After 1000 cycles, the cells showed an average of about 5% degradation. The tests addressed different stressors, such as light and heat, separately. However, in real-world conditions, these individual factors act simultaneously to affect solar cell performance. When combined, for example, light and heat significantly accelerate performance degradation or cause new problems that were otherwise absent or occurring at slower rates when testing separately. The researchers concluded that high temperature and illumination is the most critical combination of stressors for understanding how well a perovskite solar cell will perform outdoors. nrel.gov. Perovskite solar cells should be subjected to a combination of stress tests simultaneously to best predict how they will function outdoors, according to researchers at the DOE’s National Renewable Energy Laboratory. (800)293-5585 info@gtmc3.com GasTurbineMaterialsAnd CoatingsSolutionsLLC.com Gas Turbine Materials and Coating Solutions LLC Materials consulting for aero and industrial gas turbine materials technology CONSULTING SERVICES Do you need to consult with an expert engineer? Learn more about what we can do for you.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 10 MACHINE LEARNING | AI The School of Engineering and Sciences at Tecnológico de Monterrey’s Guadalajara campus and Wizeline, a tech services company, are launching the first generative artificial intelligence (AI) laboratory in Mexico and Latin America, named G.AI.L. The lab will serve as a central AI hub for the region. wizeline.com. BRIEF EXASCALE SUPERCOMPUTERS AND AI The DOE’s Argonne National Laboratory, Lemont, Ill., is building one of the first exascale systems in the U.S., named Aurora. To prepare codes for the scale of the new supercomputer, 15 teams are taking part in the Aurora Early Science Program through the Argonne Leadership Computing Facility. “The power of exascale supercomputers combined with advances in AI will provide a huge boost to the process of materials design and discovery,” says computational scientist Anouar Benali. He is leading a project to prepare a materials science and chemistry code called QMCPACK for Aurora. Developed in collaboration with Intel and Hewlett Packard Enterprise, Aurora is expected to be one of the world’s fastest supercomputers. QMCPACK is an open source code that uses the Quantum Monte Carlo (QMC) method to predict how electrons interact with one another for a wide range of materials. “With each new generation of supercomputer, we are able to improve QMCPACK’s speed and accuracy in predicting the properties of larger and more complex materials,” says Benali. “Exascale systems will allow us to model the behavior of materials at a level of accuracy that could even go beyond what experimentalists can measure.” Ultimately, the computations will help guide and speed up experiments aimed at discovering new materials. The QMCPACK team works closely with experimental groups to help pinpoint strong candidates for testing in a laboratory. “We want our experimental colleagues to be able to focus on a shortlist of the most promising materials,” adds Benali. “So having reliable simulations is becoming an increasingly important part of the materials design and discovery process.” anl.gov. AI TO DEVELOP HYDROGEN FUEL CELL CATALYSTS Proton exchange membrane hydrogen fuel cells used in hydrogen Aurora supercomputer at Argonne National Laboratory. vehicles require platinum catalysts to facilitate the oxygen reduction reaction at the anode. However, numerous elemental combinations and compositions could be explored in order to find alternatives to expensive platinum catalysts. Now, scientists at the Korea Institute of Science and Technology (KIST) have presented a new AI-based catalyst screening method and succeeded in developing a new catalytic material stemming from a ternary element- based alloy. It is less costly and performs more than twice as well as pure platinum catalysts, according to the researchers. The team developed the Slab Graph Convolutional Neural Network AI model to accurately predict the binding energy of adsorbates on the catalyst surface. Researchers were able to explore the potential of nearly 3200 ternary candidate materials in just one day, a task that would have taken years using the density functional theory adsorption energy simulation calculations traditionally employed to predict catalyst properties. The scientists developed the novel ternary alloy (Cu-Au-Pt) catalyst through experimental validation of 10 catalysts that showed potential to outperform the usual platinum versions. The new catalyst uses just 37% of the platinum required for pure platinum catalysts, and the kinetic current density is more than twice as high. https://eng. kist.re.kr. Graphical abstract of machine learning-driven hydrogen fuel cell catalyst design. Courtesy of KIST.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 1 1 PROCESS TECHNOLOGY DRY MANUFACTURING FOR BETTER BATTERIES Scientists at the DOE’s Oak Ridge National Lab (ORNL), Tenn., are exploring the benefits of a dry manufacturing process to make the electrodes in lithium-ion batteries. These electrodes are usually made using a wet slurry with toxic solvents, an expensive manufacturing approach that poses health and environmental risks. ORNL’s new method could offer a path to cleaner, more affordable high-energy electric vehicle (EV) batteries. Their process eliminates the solvent while showing promise for delivering a battery that is durable, less weighed down by inactive elements, and able to maintain high energy storage capacity after use. Such improvements could boost wider EV adoption, helping to reduce carbon emissions and achieve environmental regulation goals. According to the researchers, their enhanced material is more flexible and much more comfortable to wear than traditional nanofoam, and the material dynamically responds to external jolts due to the way the ion clusters and networks are fabricated in the material. The team expanded on previous work where they explored the use of liquids in nanofoam to create a material that meets the complex safety demands of high-contact sports. Their new liquid nanofoam process allows the interior material of the helmet to compress and disperse the impact force, minimizing the force transmitted to the head and reducing the risk of injury. It also regains its original shape after impact, allowing for multiple hits and ensuring the helmet’s continued effectiveness in protecting the athlete’s head during the game. The same liquid properties that make this new nanofoam safer for athletic gear also offer a potential use in other places where collisions happen, like cars, whose safety and material protective systems are being reconsidered to embrace the emerging era of electric propulsion and auto- mated vehicles. virginia.edu. Dry processing is a relatively new alternative that saves factory floor space as well as time, energy, waste disposal, and startup expenses. Until now, researchers have had limited understanding of how and why it works. The ORNL team discovered that batteries made using the dry process showed an extraordinary ability to maintain their capacity after extended use. Also, they are highly chemically desirable because their structure allows lithium ions to take a more direct path between the anode and cathode. These advantages reflect a high energy density and good long-term cyclability. The electrode can bend and flex well, demonstrating excellent mechanical strength and the winding capability needed for mass production of batteries. The dry process could offer a variety of benefits to manufacturers—it’s highly compatible with current state-of-theart electrode manufacturing equipment and its reduced environmental impact makes battery plants suitable in more places. ornl.gov. NANOFOAM DESIGN BREAKTHROUGH Nanofoam just received a big upgrade from a team of researchers working with the material at the University of Virginia. Integrating nanofoam with ionized water instead of regular water, the team designed a new versatile and responsive material for use in protective sports equipment, car safety features, and wearable medical devices. ORNL researchers found that a battery anode film, made using a dry process, was strong and flexible. These characteristics make a lithium-ion battery safer and more durable. Courtesy of Navitas Systems. This diagram illustrates how a liquid nanofoam cushion responds to an impact. BRIEF TriTech Titanium Parts, Detroit, was awarded the grand prize for design excellence at PowderMet 2023 in the military/firearms category. TriTech uses metal injection molding to produce its Ti-6Al-4V titanium alloy ring clamp, for use within a mounting device for a rifle scope. tritechtitanium.com.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 12 MICROSCOPIC WAVEGUIDES Researchers at the University of Chicago discovered that a sheet of glass crystal just a few atoms thick could trap and carry light. The substrate was surprisingly efficient, and light could travel relatively long distances—up to a centimeter, which is quite far in the world of light-based computing. The research demonstrates what are essentially 2D photonic circuits and could open paths to new technology. The newly created system is a way to guide light—known as a waveguide—that uses extremely tiny prisms, lenses, and switches to guide the path of the light along a chip. In existing waveguides, photons always travel enclosed inside the waveguide. With this system, the scientists explain, the glass crystal is thinner than the photon itself—so part of the photon actually sticks out of the crystal as it travels. This approach makes it much easier to build intricate devices with the glass crystals, as light can be easily moved with lenses or prisms. The photons can also experience information about the conditions along the way. The researchers think these waveguides could have uses in microscopic sensors. They’re also interested in building very thin photonic circuits which could be stacked to integrate many more tiny devices into the same chip area. The glass crystal they used in these experiments was molybdenum disulfide, but the principles should work for other materials. uchicago.edu. NATURE INSPIRES SOFT ROBOTICS MUSCLES Based on a hydrogel, a new material system that functions similarly to a muscle has been developed by a research team from the Institute for Materials Science at Kiel University, Germany. The soft material can be reduced and enlarged again in a controlled manner in a short time, making it suitable for movement tasks in soft robotics. The team’s new hydrogels are thermoresponsive and, above a temperature of 32°C, they release water and reduce their volume. When the temperature EMERGING TECHNOLOGY The Association For Manufacturing Technology (AMT) and SME entered a strategic partnership to focus on workforce development, educational products and services, and student events. AMT’s education products and services will now be owned by SME and operated by its workforce development arm, Tooling U-SME. sme.org. BRIEF The hydrogel is built into a network of interconnected tubes that absorb and release water, while a graphene coating allows the material to be heated with electricity. Courtesy of Lena Saure. Co-author Hanyu Hong displays a glass crystal—visible as the thin line in the center of the plastic. Courtesy of Jean Lachat. drops, the hydrogel absorbs the water again and returns to its original volume. The process can be repeated any number of times, resulting in a kind of movement, similar to human muscles. This makes them interesting as actuator components for the development of new types of soft robots. To build the new materials system, the researchers from Kiel built a network of tiny tubes into their hydrogel. The numerous interconnected hollow tubes of a few micrometers in size allow the water to flow freely out of and into the hydrogel, thus enabling a rapid change in its volume, while an extremely thin graphene coating also makes the tubes electrically conductive. This way, researchers can heat the hydrogel with an electric current and control the water transport at the touch of a button. Due to the tissue-like properties of the hydrogel, it has potential applications in the medical sector, such as in robot-assisted surgery, artificial tissue construction, or also as an implant for controlled drug release in the human body. www.uni-kiel.de/en.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 13 SUSTAINABILITY BRIEF CATALYTIC RECYCLING PROCESS FOR MIXED PLASTICS Nearly 90% of the mixed consumer plastics thrown away or placed in recycle bins end up buried in landfills or incinerated at commercial facilities that generate greenhouse gases and airborne toxins. To address the issue, scientists at the DOE’s Oak Ridge National Laboratory in Tennessee used carefully planned chemical design, neutron scattering, and high-performance computing to help develop a new catalytic recycling process. The new method offers a promising strategy for combating plastic waste, such as bottles, packaging, foams, and carpets. When scientists compared it to using individual catalysts for each type of plastic, the new multipurpose catalyst would generate up to 95% fewer greenhouse gases, require up to 94% less energy input, and result in up to a 96% reduction in fossil fuel consumption. The new organocatalyst has proven to deconstruct multiple polymers—such as polycarbonates, polyurethanes, polyethylene terephthalates, and polyamides—in around two hours. Until now, no single catalyst has been shown to be effective on all four of these polymers. The process provides many environmental advantages by replacing harsh chemicals for deconstructing polymers, as well as offering good selectivity, thermal stability, nonvolatility, and low flammability. Its effectiveness against multiple polymers also makes it useful for deconstructing the increasing amounts of multicomponent plastics, such as composites and multilayer packaging. Small-angle neutron scattering at ORNL’s Spallation Neutron Source was used to help confirm the formation of deconstructed monomers from the waste plastics. Also, the organocatalyst deconstructs the plastics at different temperatures, which facilitates sequentially recovering the individual monomers separately and in reusable form. ornl.gov. UPCYCLING POLYESTERS A team of researchers from Tokyo Metropolitan University developed a virtually waste-free method of converting polyesters into versatile building blocks that can be converted into a wide range of valuable chemical compounds. The team used a cheap solvent called morpholine and a small amount of a titanium-based catalyst to turn polyesters into morpholine amides. Not only can they be converted into intermediate compounds for making more polyester, but they can also be easily reacted to make ketones, aldehydes, and amines—all vital families of chemicals that are used to make a vast array of other, more valuable compounds. The new process does not require expensive reagents or harsh conditions and is essentially free of chemical waste. The yield is very high, and any unreacted solvent can be easily collected. They also found that only a small amount of catalyst was required to drive the reaction at a sensible speed, while all that is needed to separate the product is simple filtration. The main reaction proceeds at normal pressure, meaning that no special reaction vessels or devices are required. This makes the reaction easily scalable, even in the lab. The team demonstrated this by taking 50 g of PET material taken from an actual PET beverage bottle and reacting it with morpholine, getting more than 70 g of morpholine amide—a yield of 90%. www.tmu.ac.jp/english. Iron and steel production contributes roughly 7% to total global carbon emissions, with 74.5% of all steel made in coal-powered plants. Retrofitting these plants five years earlier than scheduled could reduce emissions by up to 70 gigatons by 2050, equivalent to two years of net global carbon emissions. The study was compiled by an international team led by University College London. www.ucl.ac.uk. ORNL’s organocatalyst deconstructs mixed plastics e iciently and quickly. Courtesy of Jill Hemman/ORNL, U.S. Dept. of Energy. A newly developed chemical process can upcycle polyesters to morpholine amides. Courtesy of Tokyo Metropolitan University.
14 ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 Wayne Papageorge and Elvin Beach* The Ohio State University, Columbus Greg Janas* SIFCO Forge, Cleveland This entry won the prestigious DuBose-Crouse Award for unique, unusual, and new techniques in microscopy at the 2022 International Metallographic Contest. *Member of ASM International DUBOSE-CROUSE AWARD A TWO-STEP ETCHANT TO REVEAL GRAIN BOUNDARIES IN MULTIPLE ALUMINUM ALLOYS
15 ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 In the mid-6th century BCE, Plato famously stated that “our need will be the real creator,” which has been loosely translated over time to the more well-known English proverb: necessity is the mother of invention[1]. The development of this etching procedure is an example of this axiom. During classes where the authors train large groups of students (up to twenty per laboratory session) in the art of metallographic sample preparation of aluminum alloys, etching the alloys to reveal grain structures has consistently been a point of failure. Multiple aluminum alloys including 2000, 5000, 6000, and 7000 series are used during processing, characterization, and corrosion laboratory sessions. The diversity of alloys required multiple etchants and techniques that were difficult for inexperienced students to master in the limited time available in the laboratory class period. The goal of this work was to develop a single etch that reveals grain boundaries in multiple aluminum alloy series. Three important criteria were identified for a new etchant. First, the technique must be easy to learn for inexperienced metallographers. Second, the technique must be effective at distinguishing grain boundaries in several alloys of aluminum. Specifically, the 2000, 5000, 6000, and 7000 series alloys were targeted in this work since those are the alloys used primarily in the teaching laboratories. Third, the etch should produce a sample suitable for examination using only bright-field optical microscopy. An etchant that satisfies these criteria should be of interest and utility to industrial and quality control laboratories where limited equipment may be available. It would also be beneficial to laboratories that have a high employee turnover rate or work with student interns regularly. While there are several established etchants for revealing the grain structure in select alloys; Kroll’s reagent, Keller’s reagent, Barker’s reagent, and Weck’s reagent[2], none are versatile enough to reveal grain contrast across all of the aluminum alloy series. There are examples in the technical literature of researchers exploring new and alternate etching chemicals and processes for revealing grain boundaries in aluminum alloys. Mohammadtaheri et al. explored a two- step etching process similar to the method proposed here but with a different first etchant[3]. This work demonstrated effective grain etching for 2000 and 5000 series aluminum alloys; however, no other alloys were explored. Other efforts have focused on finding an improved etchant for creating grain boundary contrast in aluminum alloys joined by welding, and specifically solid state welding processes. Tamadon et al. explored numerous combinations of two-step etching to reveal the grain structure in AA6082 joined by friction stir welding (FSW)[4]. While several processes produced excellent results, these processes were not something that could be easily transferred to a novice metallographer. Many involved three steps with an attack etch, followed by an etch to remove any Al2O3 on the surface, followed by a final etch to either stain or enhance grain contrast. Several procedures involved heat and ultrasonic baths which adds additional variables and creates a difficult process to reproduce each time. Beach et al. previously published work on a modified Barker’s reagent etch for revealing grain contrast and the oxide stir line in FSW joints[5]. This etch showed limited effectiveness on the 6000 series alloys and did not produce uniform grain contrast for dissimilar welds. The research conducted here presents a versatile new etching technique that fills the need for grain etching in multiple aluminum alloy series. The procedure is a two-step etch that combines an attack etchant with a stain etchant to reveal grain structure of 2000, 5000, 6000, and 7000 series aluminum alloys. Details of the etchant chemistry, procedures, and results are presented in a full paper published in Metallography, Microstructure, and Analysis[6]. EXPERIMENTAL PROCEDURES Samples of flat rolled aluminum alloy (AA2024-T3, AA5754-O, AA6061-T6, and AA7075-T6) sheets (approximately 3 mm in thickness) were sectioned and oriented in the mount so the rolling direction was polished and etched. Metallographic sample preparation followed methodology specified in ASTM E3-11(17)[7]. Details of the metallographic process are provided in the full paper published in Metallography, Microstructure, and Analysis[6]. The etching process developed is a two-step etch that requires applying an attack etch first followed by a stain etch. Both formulations are modified versions of established etchants. The first etching solution uses a modified version of Keller’s reagent. The formula for this reagent is: 3 mL HNO3, 2 mL HCl, 2 mL HF, and 93 mL distilled or deionized water. The second etching solution is a modified version of Weck’s reagent. The second etchant mixture was: 2 g sodium hydroxide (NaOH), 3.80 g potassium permanganate (KMnO4), and 100 mL distilled or deionized water. TABLE 1 — ETCHING TIMES FOR STEPS 1 AND 2 Alloy Designation Step 1 Modified Keller’s Reagent Step 2 Modified Weck’s Reagent AA2024-T3 10-15 sec 10-15 sec AA5754-O 15 sec 30 sec AA6061-T6 10-15 sec 15-20 sec AA7075-T6 5-10 sec 5-10 sec AA7475-T61 5-10 sec 5-10 sec
16 ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 has been the most problematic of all alloys during laboratory-based classes. The new etching procedure provides not only an improvement over other etches, but one that is easy to use and train new users for immediate success. Aluminum alloys in the 7000 series are typically etched effectively using Keller’s reagent to reveal grain structure. The Papageorge two-step etch also produced effective grain contrast in AA7475-T61 as shown in Fig. 1d. While there is no advantage of this etchant as compared to Keller’s reagent etching, this information was included in the study as having the ability to use one etching procedure across all alloys is desirable for some laboratories (including a teaching laboratory for undergraduate students). Another application where the Papageorge two-step etching procedure provides advantages for metallographers is for examining joining of dissimilar alloys. Figure 2 presents The etching process begins by lightly swabbing the polished surface of the sample in a circular fashion using the modified Keller’s reagent. The application time for the first etchant varies by alloy series, and the best practices based on results obtained here are listed in Table 1. After the first etchant is rinsed away with water, followed by ethanol, then the sample is submerged in the modified Weck’s reagent, while slowly rotating in a circular motion, for the times indicated in Table 1. The samples were rinsed in flowing water, rinsed with ethanol, dried using warm air, and examined using bright-field optical microscopy. Optical micrographs were collected at magnifications in the range of 100 – 500x. All micrographs were collected in bright-field (BF) mode. Resistance spot weld (RSW) samples between a 6000 and 7000 series alloy were also prepared and etched in this work. Those images were collected using an Olympus DSX510 optical micro- scope with a linear motion x-y stage. RESULTS AND DISCUSSION The etching procedure, which the authors refer to as the Papageorge two-step etch, was found to be effective on multiple aluminum alloys. Table 1 shows the times that were found to be optimal for creating grain contrast without creating pitting on the surface. Figure 1 shows the results from AA2024-T3, AA5754-0, AA6061-T6, and AA7475-T61 in the rolling direction at magnifications of 500x. The images in Fig. 1 were collected in BF mode with no polarizer, quarter wave plate, or lambda plate required. The AA2024 alloy was the only alloy that exhibited a color variation after etching. The AA2024 alloy has at least 4 wt% copper in the alloy that is distributed in the matrix and present in precipitates. The copper content is an order of magnitude (or more) higher than any other alloy investigated in this work. The Weck’s stain etch appears to interact with the copper and form films on the surface of the grains that create the apparent color in this alloy. While the goal of this process is not to create a color etchant, the color helps to delineate the grain boundaries in this alloy and produces visually interesting micrographs of the grains. Additional work is required to understand this effect in more detail and that work is underway. Grain structure was also revealed in AA5754-O as shown in Fig. 1b. The anneal on this sample appears to be incomplete. Aluminum alloy 6061 is regarded as a difficult alloy to etch for grain contrast. While there are suggested etchants in ASM Handbook, Volume 9[2], none are particularly consistent or easy for novice metallographers to use to reveal the grain structure. The Papageorge two-step produced an excellent grain etch on AA6061-T6 shown in Fig. 1c. The etching process creates a high level of contrast at the grains and did not create significant pitting on the polished cross-section. The ability to consistently create high contrast etching at the grain boundaries of AA6061 Fig. 1 — Bright-field optical micrographs of a nominally 3 mm thick sheet of (a) AA2024-T3, (b) AA5754-O, (c) AA6061-T6, and (d) AA5754-T61 in the rolling direction. Micrographs were collected at 500x original magnification. (d) (a) (b) (c)
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