17 20 31 P. 12 MARCH 2024 | VOL 182 | NO 2 Extreme High Speed Laser Application Trends in Titanium Alloy Development HTPro Newsletter Included in This Issue GAME-CHANGING TECHNOLOGICAL ADVANCEMENTS FOR SPACE AEROSPACE MATERIALS AND TESTING
17 20 31 P. 12 MARCH 2024 | VOL 182 | NO 2 Extreme High Speed Laser Application Trends in Titanium Alloy Development HTPro Newsletter Included in This Issue GAME-CHANGING TECHNOLOGICAL ADVANCEMENTS FOR SPACE AEROSPACE MATERIALS AND TESTING
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 EXTENDED TO MARCH 8, 2024 imatevent.org ORGANIZING PARTNER: CO-LOCATED WITH: IFHTSE World Congress
44 ASM NEWS The latest news about ASM members, chapters, events, awards, conferences, affiliates, and other Society activities. GAME-CHANGING TECHNOLOGICAL ADVANCEMENTS FOR NEXT-GEN SPACE EXPLORATION Thomas N. Ackerson Several key materials processes and techniques positively impact weight reduction and reusability of parts designed for travel to the moon, Mars, and beyond. 12 ADVANCED MATERIALS & PROCESSES | MARCH 2024 2 The dome of the liquid oxygen tank for NASA’s Space Launch System rocket will form part of the core stage that will power NASA’s Artemis III mission. Engineers rotate the dome to attach it to the previously joined forward dome and aft barrel segments using friction-stir welding. The liquid oxygen tank is one of five major components that make up the SLS rocket’s core stage. Courtesy of NASA. On the Cover: 56 3D PRINTSHOP A look at creating large aluminum parts at fast speeds and investigating defects by listening to the material as it prints. AEROMAT SHOW PREVIEW The 35th AeroMat Conference and Exposition joins up with AeroTech in Charlotte, North Carolina. 29
4 Editorial 5 Research Tracks 5 Feedback 10 Machine Learning 6 Metals/Polymers/Ceramics 8 Testing/Characterization 11 Nanotechnology 55 Editorial Preview 55 Special Advertising Section 55 Advertisers Index 56 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 worldwide 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. 182, No. 2, MARCH 2024. Copyright © 2024 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. 17 TECHNICAL SPOTLIGHT EXTREME HIGH SPEED LASER APPLICATION: A REVOLUTION IN COATING AND REPAIR TECHNOLOGY A new process offers efficient deposition of highperformance materials in aerospace manufacturing, providing key advantages compared to conventional laser cladding. 20 A SUMMARY OF Ti-2023: THE WORLD CONFERENCE ON TITANIUM Vasisht Venkatesh and Adam Pilchak The 15th World Conference on Titanium included papers on titanium alloy development, efforts to reduce Ti powder costs, additive manufacturing, and computational materials modeling tools. 24 ALUMINUM CONTINUES TO SHINE IN COMMERCIAL AIRCRAFT APPLICATIONS Robert Sanders and Graeme Marshall This article explores a brief history of the special alloys, tempers, and product forms required to meet the unique challenges of flight. FEATURES MARCH 2024 | VOL 182 | NO 2 ADVANCED MATERIALS & PROCESSES | MARCH 2024 3 17 24 31 20 31 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.
4 ADVANCED MATERIALS & PROCESSES | MARCH 2024 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 Mark F. Smith, 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 Carrie Wilson, Interim 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. SOARING INNOVATIONS The evolution of aluminum use in aircraft applications over the past 100 years is chronicled in this issue by co-authors from Novelis. In fact, an aluminum alloy was initially used by the Wright brothers in their first aircraft’s engine. The rest of that early plane consisted of wood and canvas. During a recent trip to Dayton, Ohio, I visited a reconstruction of the original 1905 Wright Flyer III on display at Carillon Historical Park’s Wright Brothers National Museum in a building partially designed by Orville Wright himself. My docent provided more details about the Flyer’s original wood and canvas materials. The wings of that early aircraft were covered in cotton muslin. The fabric was sewn on a bias—not vertically or horizontally—in order to better control air flow. The frame was made of wood— spruce painted gray to look like metal. It was a clever ploy to give potential imitators the impression the frame was metal, which would have been too heavy for flight in that day. Other minor parts were created from ash wood. Steel was only used in the springs located under each wooden bar to provide some give. The propeller was made of laminated spruce, which had to be carefully hand carved, to achieve just the right balance. In addition to settling on those materials, the Wrights had to solve many design and mechanical issues. To eliminate the distortion put on the blade by the pressure of the flight, they angled the tip and thus created a “bent end” feature on the propellers. They solved control and balance issues by mimicking a bird’s motions, which led to their experiments with “wing warping.” And they famously used a wind tunnel to test out new wing designs. On October 5, 1905, Wilbur Wright circled above Huffman Prairie, near Dayton, for over 39 minutes. This achievement exceeded the total time of the brothers’ 109 combined flights in 1903 and 1904, setting a new aviation milestone. Recognized as the world’s first practical airplane, the Wright Flyer III is designated as a National Historic Landmark. The Wright brothers had to innovate everything as they explored the new world of flight. Fast forward to the early pioneers of space exploration— they too learned to innovate for a radically different environment. As discussed by our lead article’s author, Tom Ackerson of Blue Origin LLC, new challenges are faced every day by those creating rocketry and launch systems for travel to the moon, Mars, and beyond. Yet, engineering ingenuity continues to provide solutions through new materials, processes, and technologies. For those involved in solving today’s challenges in air and space, we invite you to attend AeroMat 2024 this March in Charlotte, North Carolina. Check out the Show Preview for details. Tack on an excursion to the Outer Banks and stand atop the hill where two famous sons of Ohio launched more than 1000 glider flights. Then visit the Monument to a Century of Flight at Kitty Hawk and begin to imagine the aeronautical engineering feats of the next century. joanne.miller@asminternational.org Wright Flyer III. Courtesy of Dayton History.
ADVANCED MATERIALS & PROCESSES | MARCH 2024 5 FROM SOLAR ENERGY TO HYDROGEN Researchers from the University of California, Davis and Martin Luther University in Germany developed a new method to accurately measure photovoltage—an essential step toward finding the best conditions to make fuel from sunlight and water. Scientists can already determine the electric energy output of solar cells by using wires that connect the cell and a measuring device. However, this energy output is harder to measure in solar fuel electrodes that are in contact with water because pure water is not electrically conductive. In the new study, the team found that the photovoltage of such solar fuel electrodes can be measured in a contactless way. They did this by using a gold Kelvin probe that hovers over the illuminated device and picks up the information wirelessly. The researchers conducted contactless photovoltage measurements on bismuth vanadate, a semiconductor for water oxidation, and on copper gallium selenide, a semiconductor for hydrogen generation from water. They covered the semiconductors with water solutions and a glass slide, then placed the microscopy slide under the Kelvin probe. The team discovered that the photovoltage depends not only on the semiconductor, but also on the color of RESEARCH TRACKS / FEEDBACK ERRATA In the July/August 2023 issue, the article “Identification of Sustainable Tonewoods for Acoustic Guitars Using Materials Selection Software” by James D. Cotton and John D. Wolodko stated that the ANSYS Granta Selector database contains 498 tree species. The actual number is 214 when reduced for separate longitudinal and transverse entries and engineered wood products. This has been corrected online in the digital edition available at asminternational.org. FEEDBACK We welcome all comments and suggestions. Send letters to joanne.miller@asminternational.org. A semitransparent gold Kelvin probe measures the photovoltage of an illuminated semiconductor film in contact with an electrode and a water solution. Courtesy of UC Davis. the light, the light intensity, and the chemical properties of the water solution. They say this information will enable scientists to identify the best conditions for the direct conversion of solar energy into hydrogen and other fuels. ucdavis.edu. FAST-CHARGING LITHIUM BATTERIES With funding from the U.S. DOE’s Basic Energy Sciences Program, scientists at Cornell University, Ithaca, N.Y., developed a lithium battery that can charge in less than five minutes while maintaining stable performance over numerous cycles. The new technology could help alleviate the range anxiety common among those who worry electric vehicles cannot travel long distances without a lengthy recharge. Lithium-ion batteries are among the most popular means of powering electric vehicles because they are lightweight, yet they take hours to charge. The Cornell team identified indium as a promising material for fast-charging batteries, as it features two crucial characteristics as a battery anode: an extremely low migration energy barrier and a modest exchange current density. The combination of those qualities is essential for fast charging and longduration storage. The new technology paired with wireless induction charging Charging an EV in less than five minutes could help alleviate range anxiety. Courtesy of DOE/NREL. on roadways would shrink the size and cost of batteries, making electric transportation more feasible. The indium anodes are not perfect however. “While this result is exciting, in that it teaches us how to get to fast-charge batteries, indium is heavy,” says researcher Lynden Archer. “Therein lies an opportunity for computational chemistry modeling, perhaps using generative AI tools, to learn what other lightweight materials chemistries might achieve the same intrinsically low Damköhler numbers.” cornell.edu.
ADVANCED MATERIALS & PROCESSES | MARCH 2024 6 METALS | POLYMERS | CERAMICS On January 25, thyssenkrupp Materials de México inaugurated a $37 million service center in San Luis Potosí, Mexico. Among the benefits of the new facility is a Schuler processing line that enables cutting raw pieces of aluminum and high-strength steel for lightweighting applications in the automotive industry. thyssenkrupp.com. POLYMER NETWORKS DAMPEN SOUND In a quest to better understand how network connectivity and bond exchange mechanisms govern the overall damping behavior of polymer networks, researchers at the University of Illinois Urbana-Champaign synthesized networks with two distinct architectures and crosslink points capable of dynamically exchanging polymer strands. The incorporation of dynamic bonds into the polymer network demonstrates excellent damping of sound and vibrations at well-defined frequencies. The ability to tailor polymers that absorb specific frequencies can be beneficial for use in ear plugs and helmets, as well as in scenarios with repeat exposure to a certain frequency of noise. “The key advance here is that we’re using dynamic covalent bonds,” explains lead researcher Chris Evans. Incorporating orthogonal bonds, where fast bonds can only exchange with other fast bonds and slow bonds can only exchange with other slow bonds, generates multiple and well-separated relaxation modes, giving the network excellent damping and improved mechanical properties. FILMING ATOMIC HYDROGEN FLOW A group of researchers at Tohoku University, Japan, developed a simple and inexpensive method to visualize the atomic state of hydrogen. Increased integration of hydrogen-based energy requires overcoming some significant technical issues—necessitating structural and functional materials that produce, store, transport, and preserve hydrogen. To develop advanced materials for hydrogen-related applications, a fundamental understanding of how hydrogen behaves in alloys is crucial. The group’s new visualization technique utilizes an optical microscope and a polyaniline layer, enabling researchers to successfully film the flow of hydrogen atoms in pure nickel (Ni). The color of polyaniline changed from purple to white when reacting with hydrogen atoms in a metal, and in-situ visualization revealed that hydrogen atoms in pure Ni preferentially diffused through grain boundaries in disordered Ni atoms. Furthermore, the group found that hydrogen diffusion was dependent on the geometrical structure of the grain boundaries—the hydrogen flux grew at grain boundaries with large geometric spaces. These results experimentally clarified the relationship between the atomic-scale structure of pure Ni and the hydrogen diffusion behavior. The approach has broader applications as well. It can be applied to other metals and alloys, such as steel and aluminum, and drastically facilitates elucidating the microscopic hydrogen-material interactions, which could be further investigated through simulations. According to the researchers, understanding hydrogen behaviors related to the atomic-scale structure of alloys will enable more efficient alloy design, dramatically accelerating the development of highly functional materials and a shift toward a more hydrogen energy-based society. www. tohoku.ac.jp/en. Stardust Power Inc. will break ground on a $1 billion battery-grade lithium refinery in Muskogee, Okla., by mid-2024. The facility will serve as a central location for lithium inputs to be delivered and refined into lithium products for delivery across the U.S. stardust-power.com. BRIEFS Researchers have discovered a technique for depicting the microscopic flow of hydrogen atoms in metal. Courtesy of Tohoku University. Materials science and engineering professor Chris Evans. Courtesy of the University of Illinois UrbanaChampaign.
ADVANCED MATERIALS & PROCESSES | MARCH 2024 7 The team created a series of polymers that controlled certain types of architectures and backbones and then observed the way the polymer chains connected. Evans says the way the polymer chains are linked makes a big difference in tuning the energy dissipating processes at very specific time- scales, which in turn correspond to specific sound waves or vibrations. If chains are only linked at the ends, it’s not as effective as being linked periodically along the chain backbone. Evans indicates his group is now working on ways to engineer the polymer to be more of a self-standing material. In the future, they also aim to incorporate more dynamic bonds, so the polymer isn’t only tailored for a specific frequency, but for a much wider range of frequencies. illinois.edu. FIRST 2D HEAVY FERMION Researchers at Columbia University, New York, successfully synthesized the first 2D heavy fermion material. The new material, a layered intermetallic crystal composed of cerium, silicon, and iodine (CeSiI), is a van der Waals crystal that can be peeled into layers just a few atoms thick. This makes it easier to manipulate and combine with other materials than a bulk crystal, in addition to possessing potential quantum properties that occur in 2D. With its middle sheet of silicon sandwiched between magnetic cerium atoms, the researchers suspected that CeSiI might have some interesting electronic properties. Using a scanning tunneling microscope, they observed a particular spectrum shape characteristic of heavy fermions. The team then synthesized LaSiI, a nonmagnetic equivalent to CeSiI, and weighed the electrons of both materials via their heat capacities. CeSiI’s were heavier. By comparing the two—one with magnetic spins and one without—the researchers confirmed the creation of a heavy fermion. From here, the Columbia researchers will explore the quantum behaviors of their new material. quantum.columbia.edu. Electrons that interact with magnetic spins in heavy fermion materials have a heavier-than-usual effective mass. Courtesy of Nicoletta Barolini, Columbia University. 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 ADVANCED MATERIALS & PROCESSES | MARCH 2024 VISUALIZING NANOSCALE FORCES OF LIGHT At the University of Illinois Urbana- Champaign’s Beckman Institute for Advanced Science and Technology and the Nick Holonyak Micro and Nanotechnology Laboratory, researchers developed a groundbreaking microscope that visualizes the invisible forces exerted by light at the nanoscale. Using their newly created tool—Decoupled Optical Force Nanoscopy (Dofn)— the researchers explored the mechanics of how light can generate minute forces upon nanoscale specimens. “Dofn acts as a bridge over previous technological gaps, giving us the ability to explore and quantify how light-induced forces manifest as both pressure and heat at the nanoscale,” says researcher Hanwei Wang. These observations mark a paradigm shift in scientists’ ability to understand and TESTING | CHARACTERIZATION MAPPING ATOMIC COORDINATES IN 3D For the first time, researchers mapped the 3D atomic coordinates of medium- and high-entropy alloys. Led by University of California, Los Angeles (UCLA) scientists, the research team used an advanced imaging technique to gain novel views of the alloys’ structure and characteristics. In another scientific first for any material, the researchers correlated the mixture of elements with structural defects. The researchers focused on twin boundary formation, which is understood to be a key factor in medium- and high-entropy alloys’ unique combination of toughness and flexibility. Twinning happens when strain causes one section of a crystal matrix to bend diagonally while the atoms around it remain in their original configuration, forming mirror images on either side of the boundary. The team used an array of metals to make six medium-entropy alloy nano- particles, combining nickel, palladium, and platinum. Four nanoparticles of a high-entropy alloy combined cobalt, nickel, ruthenium, rhodium, palladium, silver, iridium, and platinum. The scientists liquified the metal at over 2000°F for five-hundredths of a second, then cooled it down in less than one-tenth that time. The shock of the process induced twin boundaries in six of the 10 nanoparticles—four of those each had a pair of twins. To identify the defects, the researchers developed a new technique called atomic electron tomography, and then mapped each atom in the medium-entropy alloy nanoparticles. The researchers observed that the more atoms of different elements are mixed, the more likely the alloy’s structure will change in a way that contributes to matching toughness with flexibility. The findings could inform the design of medium- and high- entropy alloys with added durability and even unlock potential properties currently unseen in steel and other conventional alloys by engineering the mixture of certain elements. ucla.edu. Triangular holes make this material more likely to crack from left to right. Courtesy of N.R. Brodnik et al./Phys. Rev. Lett. Oxford Instruments plc, U.K., acquired First Light Imaging SAS, France, a manufacturer of high-speed, low-noise scientific cameras for infrared and visible imaging, with applications in astronomy and the life sciences. oxinst.com. Bruker, Billerica, Mass., acquired Nion, Kirkland, Wash., a manufacturer of advanced scanning transmission electron microscopes (STEM). Nion was the first to introduce aberration correction for STEM instruments with ultra-high stability for the highest resolution images. bruker.com. BRIEFS The study’s authors from Beckman Institute include, from left: Catherine Murphy, Hanwei Wang, Yang Zhao, and Yun-Sheng Chen. Atomic map of a high-entropy alloy nanoparticle shows different categories of elements in red, blue, and green, and twinning boundaries in yellow. Courtesy of Miao Lab/UCLA.
ADVANCED MATERIALS & PROCESSES | MARCH 2024 9 harness the power of light in nanotechnology and beyond. The researchers say their new technique promises a wide range of applications in nanophononics, nanomedicine, mechanochemistry, mechanobiology, and biophysics—from improving the precision of drug delivery to refining the design of nanodevices. This research underscores the potential of interdisciplinary collaboration in pushing the boundaries of biological and medical science. beckman.illinois.edu. NEW TWIST IN MATERIALS DESIGN A new discovery reveals that crystals can twist when they are sandwiched between two substrates—a critical step toward exploring new material properties for electronics and other applications. In California, researchers from the DOE’s SLAC National Accelerator Laboratory, Stanford University, and the DOE’s Lawrence Berkeley National Laboratory grew a twisted multilayer crystal structure for the first time and measured the structure’s key properties. The twisted structure could help researchers develop next-generation materials for solar cells, quantum computers, lasers, and other devices. Researchers added a layer of gold between two sheets of a traditional semiconducting material, molybdenum disulfide (MoS2). Because the top and bottom sheets were oriented differently, the gold atoms could not align with both simultaneously, which allowed the Au structure to twist. To study the gold layer in detail, the team heated a sample of the whole structure to 500°C. Then they sent a stream of electrons through the sample using transmission electron microscopy (TEM), which revealed the morphology, orientation, and strain of the gold nanodiscs after annealing at different temperatures. Measuring those properties of the gold nanodiscs was a necessary first step toward understanding how the new structure could be designed for future real-world applications. Next, researchers want to further study the optical properties of the gold nanodiscs using TEM and learn if their design alters physical properties like the band structure of Au. slac.stanford.edu. The MoS2 layers and gold nanodiscs marked by regions indicate the various layers of the sample. Gold is found on the bottom MoS2 layer (I), below the top layer (II), and between the top and bottom layers (III). The gold nanodiscs are the darker regions in III. Courtesy of Yi Cui/Stanford University. STAY AHEAD OF YOUR PROFESSIONAL JOURNEY WITH ASM EDUCATION & TRAINING. EARN CEUs, ENJOY DISCOUNTS, NETWORK, AND LEARN FROM INDUSTRY EXPERTS. SCAN TO ENROLL TODAY Education
ADVANCED MATERIALS & PROCESSES | MARCH 2024 10 MACHINE LEARNING | AI AI SHEDS LIGHT ON CRYSTAL GROWTH Researchers at Nagoya University, Japan, recently used artificial intelligence to analyze the image data of polycrystalline silicon, a material widely used in solar panels. The AI created a 3D model in virtual space, helping the team identify areas where dislocation clusters were affecting the material’s performance. The scientists then used electron microscopy and theoretical calculations to understand how these areas formed. These techniques revealed stress distribution in the crystal lattice and found staircase-like structures at crystal grain boundaries that appear to cause dislocations during crystal growth. In addition to understanding how to improve solar cells, the study could have important implications for the science of crystal growth and deformation. For starters, the new research could add to the Haasen-Alexander- Sumino (HAS) model—a theoretical framework used to understand the behavior of dislocations in materials. Researcher Noritaka Usami believes his team found dislocations that the HAS model missed. Another discovery occurred when the team calculated the arrangement of atoms in the polycrystalline structures. They found unexpectedly large tensile bond strains along the edge of the staircase-like struc- tures that triggered dislocation generation. “As experts who have been studying this for years, we were amazed and excited to finally see proof of the presence of dislocations in these structures. It suggests that we can control the formation of dislocation clusters by controlling the direction in which the boundary spreads,” says Usami. www.nagoya-u.ac.jp. SPEEDY SOLAR CELL PRODUCTION Scientists at RMIT University along with colleagues at Monash University and CSIRO, all in Australia, are using AI to produce solar cells from perovskite in a matter of weeks, saving years of human labor and potential errors. Lead researcher Nastaran Meftahi said scientific teams worldwide have been racing to make perovskite cells, which are less expensive than silicon and now stable enough for longterm commercial use. “Until now, the process of creating perovskite cells has been more like alchemy than science—record efficiencies have been reached, but positive results are notoriously difficult to reproduce,” 3D model generated by AI helps scientists explore complex polycrystalline materials. she said. “What we have achieved is the development of a method for rapidly and reproducibly making and testing new solar cells, where each generation learns from and improves upon the previous.” Using a multimillion-dollar automated system for solar cell manufacturing being built by Adam Surmiak at Monash University, the model will be able to predict huge volumes of promising chemical recipes for new perovskite solar cells. The facility is currently under construction. So far, the scientists’ work has resulted in reproducible perovskite solar cells with power-conversion efficiencies of 16.9%, the best-known efficiency manufactured without human intervention. Surmiak’s team designed and characterized 16 new solar cells never seen before using his innovative setup, and Meftahi employed these cells to predict the properties of 256 new solar cell recipes. “At Monash, they’ll soon be able to make 2000 unique solar cells per day. We’re quickly getting to the stage where we’ll be able to predict the properties of millions of different cells,” says Meftahi. www.rmit.edu.au. Adam Surmiak working with automatic device characterization equipment. Courtesy of Australian Research Council.
ADVANCED MATERIALS & PROCESSES | MARCH 2024 1 1 NANOTUBES HELP HELMETS TOUGHEN UP A new material developed by University of Wisconsin-Madison engineers could mitigate or even prevent traumatic brain injuries when used as helmet lining. The material—a vertically aligned carbon nanotube foam— weakens rotational kinetic energy before it reaches the brain. In fact, the material is 30 times better at absorbing energy in shear than the foam currently used in U.S. military combat helmet liners. At present, some helmets attempt to reduce rotational motion from impacts by employing a layer that allows a sliding motion to occur between the wearer’s head and the helmet’s outer shell. However, these moving layers don’t dissipate energy in shear and tend to jam when severely compressed. Since the new material doesn’t rely on sliding layers, it sidesteps these shortcomings. Furthermore, when it’s compressed, the material gets unusually better at accommodating shear and dissipating energy from an impact, according to the researchers. The new foam consists of carbon nanotubes that are carefully arranged into closely packed cylindrical structures. The material’s novel architecture, which has unique structural features across multiple length scales, gives the material its exceptional properties. In addition, the researchers recently demonstrated that their foams exhibited outstanding thermal conductivity and diffusivity, which would enable a helmet liner made of the material to keep the wearer’s head cool in hot environments. Coupled with its thinness, that cooling capability puts the new material on par with graphite foams and makes it attractive for applications where less weight is important. Beyond helmet liners, the material could also be used in electronic packaging and electronic systems to both protect against shocks and keep electronics cool. wisc.edu. MAKING MATERIALS FROM MARS WASTE Using resources and techniques currently applied on the International Space Station and by NASA, a research group at the University of Sussex, U.K., is investigating the potential of nanomaterials for clean energy production and building materials on Mars. Taking what was considered a NANOTECHNOLOGY Bhanugoban Maheswaran tests the vertically aligned carbon nanotube foams in Assistant Professor Ramathasan Thevamaran’s lab. Courtesy of Joel Hallberg. waste product by NASA and applying only sustainable production methods, including water-based chemistry and low-energy processes, the researchers have successfully identified electrical properties within gypsum nano-materials. Resulting materials could have a range of applications from creating clean hydrogen fuel to developing an electronic device similar to a transistor, to creating an additive to textiles to increase their robustness. The researchers say their findings open avenues for sustainable technology—and building—on Mars but also highlight the broader potential for eco-friendly breakthroughs here on Earth. To make the discovery, the researchers used NASA’s innovative method for extracting water from Martian gypsum, which is dehydrated by the agency to get water for human consumption. This produces a byproduct called anhydrite, considered waste material by NASA, but now shown to be hugely valuable. The Sussex researchers processed anhydrite into nanobelts—essentially tagliatelleshaped materials—demonstrating their potential to provide clean energy and sustainable electronics. Furthermore, at every step of their process, water could be continuously collected and recycled. The group is optimistic about the process’ feasibility on Mars, as it requires only naturally occurring materials. www.sussex.ac.uk. Researchers at Rice University, Houston, developed new methods to create synthetic chiral carbon nanotube assemblies, enhancing control over the properties of polarized light. The team says these discoveries could revolutionize applications in optoelectronics, quantum computing, and other industries. rice.edu. BRIEF From le : Two types of Martian rock, a vial of nanobelts in water, and a close up of nanobelts. Courtesy of University of Sussex.
12 ADVANCED MATERIALS & PROCESSES | MARCH 2024 Thomas N. Ackerson* Blue Origin LLC, Merritt Island, Florida Several key materials processes and techniques positively impact weight reduction and reusability of parts designed for travel to the moon, Mars, and beyond. *Member of ASM International Metallic powder is brushed o a printed rocket part at the MSFC Additive Manufacturing Laboratory. Courtesy of NASA. ADVANCEMENTS FOR SPACE GAME-CHANGING TECHNOLOGICAL ADVANCEMENTS FOR NEXT-GEN SPACE EXPLORATION
13 ADVANCED MATERIALS & PROCESSES | MARCH 2024 The United States’ space launch program has played a key role in the advancement of materials science for the last seven decades. Unprecedented financial investment was initiated during the Apollo program in the 1960s and continued with the Space Shuttle program until the last flight of Atlantis on July 8, 2011. The winding down of the shuttle program gave way to significant privately funded launch system development with more unprecedented investment in recent years. These programs continue to advance materials science and engineering as the focus moves toward human travel to the moon, Mars, and beyond. Star Trek creator Gene Roddenberry gave an interesting lecture at North Carolina State University in the mid1980s while the author was working on his undergraduate degree. At the time, the United States was in the early stages of a very robust but technically challenging Space Shuttle program. Roddenberry noted that the technology boosts resulting from the Apollo and Shuttle programs would pave a fast track for space travel and he predicted that humans would be living on the moon by the year 2000. His forecast was based on extrapolating out the advances in materials science on the trajectory we were on at that time. Although his prediction did not come true, we are on track to land humans on the moon once again this decade. Modern day orbital space launches and the vision of millions of people living and working in space has required game-changing technological advancements in how rockets are engineered and built. Significant cost reduction of launch systems is needed to make space travel financially sustainable. Figure 1 shows a comparison of launch costs per kg of cargo for various launch systems over the past several decades. Recent advances in technology have reduced costs to an all-time low of $2500 per kilogram of payload. Two key technology areas that are driving these launch costs down are weight reduction and reusability. ADDITIVE MANUFACTURING One example of a technology that has been a game-changer for aerospace and other industries over the past two decades is additive manufacturing (AM). Additive manufacturing has helped the space industry reduce the weight of rocket components by allowing the fabrication of parts that were previously impossible to machine using traditional techniques. For example, internal weight-saving cavities can be designed into a part produced by AM. Figure 2 shows some examples of metallic parts produced by AM. AM technology also helps rapidly prototype parts for evaluation. The National Aeronautics and Space Administration (NASA) acknowledges that “propulsion system development requires new, more affordable manufacturing techniques and technologies in a constrained budget environment, while future in-space applications will require in-space manufacturing and assembly of parts and systems”[2]. Fig. 2 — Parts produced from metal powder using AM. Fig. 1 — Approximate payload cost per kg for various medium-heavy launch systems, adjusted for inflation[1].
14 ADVANCED MATERIALS & PROCESSES | MARCH 2024 SURFACE ANALYSIS AND COATING EXPOSURE TESTING Anyone who has ever stayed in a condo on the beach has likely noticed that the outdoor air conditioner condenser unit looked rusted, with good reason, as coastal environments are tough on materials. The combination of high-intensity sun, rain, heat, humidity, and seawater can quickly deteriorate an improperly protected metallic or composite surface. When it comes to a reusable rocket, any deterioration of the protective coating system could jeopardize hardware that is planned to be launched multiple times. A small corrosion pit, for example, could act as a fatigue crack initiation site. Much of the author’s work is focused on the analysis of advanced surface preparation of substrates and testing of protective coatings for the materials used in the construction of rockets. Surface analysis is performed using a scanning electron microscope (SEM) in conjunction with energy dispersive x-ray spectroscopy (EDS). Other common analytical methods include x-ray fluorescence (XRF) and Fourier transform infrared (FTIR) analysis. Corrosion testing utilizes a combination of indoor laboratory (i.e., salt spray) and outdoor exposure testing to qualify pretreatments and coating systems. Such testing has played a key role as the world looks to replace non- environmentally friendly cadmium (Cd) plating and hexavalent chromium (Cr+6) conversion coatings Indeed, significant research is being performed at NASA’s Marshall Space Flight Center in additive and digital manufacturing, and the application of those techniques to various materials engineering challenges. FRICTION STIR WELDING Another key technology for modern manufacturing of lightweight rocket tank structures fabricated from aluminum alloys is friction stir welding (FSW). FSW is a relatively straightforward joining technique outlined in Fig. 3 that transforms metals “from a solid state into a ‘plasticlike’ state, and then mechanically stirs the materials to- gether under pressure to form a welded joint”[4]. Following the technique’s invention in 1991, FSW was adopted by NASA for joining the external fuel tank of the Space Shuttle. The technique allowed NASA to eliminate fusion welds, whose shortcomings were problematic from a mechanical integrity standpoint. The benefit of FSW is that it can be used to join two aluminum sections without melting. Also, it is well suited for lightweight aluminum alloys, such as Al-Li 2195. The FSW process has been further refined in recent years to provide aluminum joints that are mechanically sound and suitable for the stresses encountered over multiple flight cycles. A typical microstructure resulting from the FSW process is shown in Fig. 4. REDUCE REUSE RECYCLE Imagine designing and building a fancy car with all the bells and whistles, only to take it on a long trip and then discard it at the destination. That’s a bit of a stretch, but not too far off from the Saturn V launch system used for the Apollo program. Only the capsule came back to Earth and it was not reusable (Fig. 5). Today’s orbital launch rockets incorporate advanced computerized design and modeling, unique manufacturing methods, and coating systems to protect the underlying materials. This allows the rockets to be used multiple times (Fig. 6). They must withstand the repeated mechanical and thermal stresses of launch, reentry, and landing. Because orbital launches occur oceanside for safety reasons, corrosion also comes into play for hardware that is out in the elements awaiting launch, landing on a platform at sea, or being transferred from one coastal location to another. Other hardware, such as reusable composite payload fairings that parachute into the ocean following reentry through the Earth’s atmosphere, must be able to withstand brief immersion in seawater. This is where materials analysis and simulated exposure testing help design for reusability. Fig. 3 — Schematic of friction stir welding[3]. Fig. 4 — A transverse metallographic cross-section showing the typical microstructure of a friction stir welded joint. Etched with Keller’s reagent. Fig. 5 — Apollo capsule.
15 ADVANCED MATERIALS & PROCESSES | MARCH 2024 with trivalent chromium conversion coatings. Each of the two testing methods mentioned above has its pros and cons. Salt-spray testing is performed per ASTM B117, Standard Practice for Operating Salt Spray (Fog) Apparatus[5], and can give results in a matter of hours or days (Fig. 7). This is the standard corrosion test specified in MIL-DTL-5541 for the evaluation of conversion coated aluminum substrates[6]. However, salt-spray testing is not representative of actual conditions that a launch system will see, and it can be overly aggressive. Outdoor exposure testing is a good complement to salt spray testing. The author is shown at the Seaside Atmospheric Exposure Test Facility (Fig. 8), where parts and test panels can be exposed to the outdoor environment. The facility is located adjacent to their launch pad and is representative of the local atmospheric conditions. The primary drawback of outdoor exposure testing is that it can take months or years to see how a coating system will fare in real-world coastal conditions. Fortunately, NASA has generated considerable data at their beachside facility over many decades, and much of this information is made available to the industry. A recent round-robin study was performed along with Q-Lab’s Homestead, Fla. facility and the Kennedy Space Center (KSC). The carbon steel panels used for the study were painted and scribed at the same time, using the same technique, and by the same person. After just three months of outdoor exposure, there was a distinct difference in the degree of corrosion between the three sites. The KSC facility is located on the beach and showed the greatest degree of corrosion. The test panels hung at the author’s site just 4 miles south and approximately 1000 feet inland from the beach showed less corrosion. Q-Lab’s panels showed the least amount of corrosion of the three sites, as that facility is several miles inland from the coast (Figs. 9 and 10). Fig. 6 — Modern-day reusable rocket launch and land sequence. Fig. 7 — Q-FOG cyclic corrosion tester. Image courtesy of Q-Lab. Fig. 8 — Seaside Atmospheric Exposure Test Facility, Merritt Island, Florida. Fig. 9 — Relative Florida locations of round robin test participants, north to south: Site 1, Site 2, and Site 3.
16 ADVANCED MATERIALS & PROCESSES | MARCH 2024 The lesson learned is that testing must be tuned for the intended end-use, including location of the finished product. Other factors to consider for outdoor exposure include time of year. For example, corrosion may not be as severe if testing was only performed for a few months during an extended dry season. Coatings improvement and corrosion prevention requires a combination of simulated exposure in the laboratory and real-world exposure at an outdoor facility. The process is iterative, as shown in Fig. 11. It can be time consuming, and depends on many factors such as supply chain, cost, schedule, and environmental impacts (toxicity, Zero Waste goals, etc.). As President Kennedy notably stated, “We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard.” That quote remains valid today, over 60 years later, as the design and fabrication of space launch systems continues to be a very challenging and complex undertaking. History has shown that advances in materials science and processing do not increase in a linear fashion over time, but rather in cycles; and such cycles are primarily a function of available financial and human resources. There is no doubt that humans will eventually colonize the moon, Mars, and beyond. Developing the necessary technologies to accomplish these goals will take longstanding investment, but the benefit to Earth and humankind will be unprecedented. ~AM&P For more information: Thomas N. Ackerson, P.E., principal M&P engineer – Metallurgy and Failure Analysis, Blue Origin LLC, 8082 Space Commerce Way, Merritt Island, FL 32953, 205.821.0924, tackerson@blueorigin.com. References 1. CSIS Aerospace Security Project (2022) – processed by Our World in Data, Launch Cost per Kilogram of Payload [dataset]. CSIS Aerospace Security Project (2022) [original data]. 2. NASA, Materials and Manufacturing: Additive Manufacturing: Pioneering Affordable Aerospace Manufacturing, https://www.nasa.gov/wp-content/ uploads/2015/04/additive_mfg.pdf. 3. Titanium: Physical Metallurgy, Processing, and Applications, ed. F.H. Froes, 2015, doi.org/10.31399/ asm.tb.tpmpa.9781627083188. 4. NASA, Space Shuttle Technology Summary: Friction Stir Welding, https:// www.nasa.gov/wp-content/uploads/ 2016/08/104835main_friction.pdf. 5. ASTM B117, Standard Practice for Operating Salt Spray (Fog) Apparatus, ASTM International. 6. MIL-STD-5541, Chemical Conversion Coatings on Aluminum and Aluminum Alloys, 11 July 2006. Fig. 10 — Variations in degree of corrosion a er three months of outdoor exposure between the three locations. Fig. 11 — Protective coatings improvement cycle. To appear in the listings, visit AMPdirectory.com/addyourcompany Simplify Your Search for Vendors Find the right solutions for your business. Search for products, research companies, connect with suppliers, and make confident purchasing decisions all in one place. AMPdirectory.com
ADVANCED MATERIALS & PROCESSES | MARCH 2024 1 7 Extreme high-speed laser application (EHLA) is a groundbreaking material deposition process that is disrupting the status quo and reshaping the way industry thinks about coatings technologies. Evolving from laser cladding (also known by other terms such as laser metal deposition (LMD), or laser beam-directed energy deposition (LB-DED), and laser engineered net shaping (LENS)), EHLA operates at speeds 10-100 times faster than prevailing methods. As a sustainable alternative to chrome plating, EHLA excels in material integrity, efficiency, and performance, while rapidly reducing costs compared to thermal spray and conventional laser cladding. This addresses many sustainability concerns within the manufacturing sector. EHLA operates by feeding powder from a specially designed nozzle that creates an optimized powder-gas jet stream. The particles coincide with the path of a laser beam and melt in flight, before reaching the substrate. Most of the laser energy is absorbed by the powder, but a small percentage (approximately 20%) reaches the substrate, creating a shallow molten pool, enabling a metallurgical bonding of the deposited powder to the substrate (Fig. 1). The energy and heat transferred to the substrate is low and therefore the impact is significantly less compared to conventional fusion processes such as arc weld overlay and conventional laser cladding. Without the dependency of forming a conventional meltpool, the process can therefore be sped up. There has yet to be found a limit to this besides appropriate machine technology to match, with current developments working up to deposition speeds of around 300-500 m/min. The EHLA technology was initially developed for coating rotationally symmetric components, such as hydraulic shafts and gate valve seats, utilizing the simplicity of turning the component at high speeds to create the effective surface deposition speed. Unlike the conventional laser cladding process, EHLA creates unprecedented low dilution and small heat affected zones for a fusion based process, with dilution depths as low as 5-10 µm. This allows the generation of thin coatings with desired chemistry, which can rival other fast coating processes, e.g., thermal spray, but offers stronger bonding interface and material adhesion (Fig. 2). TECHNICAL SPOTLIGHT EXTREME HIGH SPEED LASER APPLICATION: A REVOLUTION IN COATING AND REPAIR TECHNOLOGY A new process offers efficient deposition of high-performance materials in aerospace manufacturing, providing key advantages compared to conventional laser cladding. Combatting Euro 7 and China 7 emission regulations: EHLA hardfacing coated rotor produced quickly and efficiently, to reduce the wear and emissions of particulates.
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