20 24 27 P. 12 Historical Snapshot of Stress Corrosion Cracking Benefits of Remote Monitoring for Lab Test Equipment Sustainable AM Process for Making Hybrid Mining Tools HOW RESIDUAL STRESSES ARE MEASURED TESTING/CHARACTERIZATION NOVEMBER/DECEMBER 2024 | VOL 182 | NO 8
INTERNATIONAL THERMAL SPRAY CONFERENCE & EXPOSITION (ITSC) MAY 5 – 8, 2025 | VANCOUVER, CANADA ITSC is the world’s foremost international conference and exhibition for thermal spray technologists, researchers, manufacturers, and suppliers. This conference rotates between North America, Europe, and the Pacific Rim and is organized by the ASM Thermal Spray Society, the German Welding Society (DVS), and International Institute of Welding (iiw). 3RD INTERNATIONAL CONFERENCE ON QUENCHING & DISTORTION ENGINEERING (QDE) MAY 5 – 8, 2025 | VANCOUVER, CANADA This event is the global gathering for professionals and researchers in the field of quenching and distortion engineering. Join us for an immersive experience filled with cutting-edge research presentations, insightful discussions, and unparalleled networking opportunities. AEROMAT MAY 6 – 8, 2025 | VANCOUVER, CANADA AeroMat focuses on innovative aerospace materials, fabrication, and manufacturing methods that improve performance, durability, and sustainability of aerospace structures and engines with reduced life-cycle costs. 2ND SHAPE MEMORY & SUPERELASTIC TECHNOLOGIES (SMST) IRELAND MAY 22, 2025 | GALWAY, IRELAND The 2nd SMST Ireland event will be a pivotal gathering in the MedTech industry, spotlighting the dynamic role of Nitinol in design and manufacturing. With the theme “Engaging and Enabling Irish MedTech for Design and Manufacturing with Nitinol,” the conference aims to explore the transformative potential of this unique alloy in advancing medical technology. INTERNATIONAL CONFERENCE ON RESIDUAL STRESSES (ICRS) OCTOBER 20 – 23, 2025 | DETROIT, MICHIGAN Discover the forefront of residual stress research and its impact on material behavior at this enriching event. Engage with experts and practitioners across diverse fields through our symposium topics, networking opportunities, and technical programming. INTERNATIONAL MATERIALS, APPLICATIONS & TECHNOLOGIES (IMAT) OCTOBER 20 – 23, 2025 | DETROIT, MICHIGAN IMAT, ASM’s annual event, is the only targeted conference on advanced materials, applications, and technologies in key growth markets that will have a focus on economic trends and business forecasts. The event will include a diverse group of materials experts, including the ASM Programming Committees and all six of ASM’s Affiliate Societies, who are heavily involved in building the technical symposiums, which will have a strong focus on realworld technologies that can be put to use today. HEAT TREAT 2025 OCTOBER 21 – 23, 2025 | DETROIT, MICHIGAN Discover the unrivaled opportunities awaiting you at Heat Treat 2025 Conference and Expo in Detroit! As the LARGEST gathering for heat treating professionals, materials experts, and industry leaders in North America, Heat Treat is a MUST-ATTEND event! INTERNATIONAL SYMPOSIUM FOR TESTING AND FAILURE ANALYSIS (ISTFA) NOVEMBER 16 – 20, 2025 | PASADENA, CALIFORNIA ISTFA is the only North American event devoted to the semiconductor, electronic sample preparation, and imaging markets. ISTFA offers the best venue for failure analysts and the FA community for sharing challenges and acquiring the technical knowledge and resources needed to take them on. Showcase your thought leadership and innovations at one of ASMʼs 2025 conferences and expositions, which offer unparalleled access to highly engaged audiences of industry leaders and decision-makers. Learn more about each event and related exhibit and sponsorship opportunities at asminternational.org/events
20 24 27 P. 12 Historical Snapshot of Stress Corrosion Cracking Benefits of Remote Monitoring for Lab Test Equipment Sustainable AM Process for Making Hybrid Mining Tools HOW RESIDUAL STRESSES ARE MEASURED TESTING/CHARACTERIZATION NOVEMBER/DECEMBER 2024 | VOL 182 | NO 8
2025 INTERNATIONAL MATERIALS, APPLICATIONS & TECHNOLOGIES HUNTINGTON PLACE, DETROIT, MI | OCTOBER 20-23, 2025 CALL FOR ABSTRACTS NOW OPEN! ORGANIZED BY: Shape Memory & Superelastic Technologies ORGANIZING PARTNER: imatevent.org IMAT, ASM International’s annual meeting focused on membership and the materials community, offers an industry-oriented conference and exposition targeting a broad range of materials, processes, and applications, with an emphasis on advanced materials and manufacturing technologies. Traditional topics are explored, including metals, ceramics, composites, coatings, alloy development, microstructure/process/properties relationships, phase equilibria, mechanical behavior, joining, corrosion and failure analysis. Multiple student events and competitions provide an opportunity to present research and develop connections with the next generation of materials scientists. ABSTRACT SUBMISSION DEADLINE: FEBRUARY 28, 2025 Abstracts are solicited in the following areas: • Additive Manufacturing • Advanced Materials Manufacturing • Archaeometallurgy and Ancient Metalworking • Artificial Intelligence and Materials Informatics • 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 Advance 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 • Materials & Processes for Automation • Medical / Biomaterials: Driving for Delivered Patient Value • 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 • Residual Stress • Sustainable Materials & Processes • Thermal Spray and Surface Engineering
WHAT’S IN YOUR 2025 MARKETING MIX? ASM INTERNATIONAL’S 2025 MEDIA KIT is YOUR GATEWAY to reaching a targeted audience of materials science and engineering professionals. ARE YOU READY TO EXPLORE HOW ASM CAN HELP YOU ACHIEVE YOUR 2025 GOALS? VIEW THE 2025 MEDIA KIT AT: WWW.ASMINTERNATIONAL.ORG/ADVERTISE-WITH-US-RESULTS/ ASM generates measurable impact by offering unparalleled access to engaging with a unique and motivated audience through integrated, omnichannel marketing capabilities. Develop a comprehensive campaign through sponsored emails, webinars, web and mobile ad placements, in-person event sponsorships, and more to target sizable audiences of decision makers in industries such as: Aerospace Automotive Heat Treating Materials Characterization & Testing Failure Analysis Shape Memory & Medical Devices Thermal Spray And more! KELLY “KJ” JOHANNS BUSINESS DEVELOPMENT MANAGER CONTACT KJ TODAY AT: KJ.JOHANNS@ASMINTERNATIONAL.ORG OR 440.671.3851
40 HIGHLIGHTS FROM IMAT 2024 This photo gallery features some of the awards, meetings, and fun had at IMAT 2024 in Cleveland. HOW RESIDUAL STRESSES ARE MEASURED—-AN OVERVIEW Iuliana Cernatescu and James Pineault Optimize a residual stress measurement plan by understanding the methods, basic knowledge, and how to use the measured data. 12 ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2024 2 Portable XRD-based residual stress measurement system. Photo courtesy of Proto Manufacturing. On the Cover: 46 STRESS RELIEF From the lighter side of engineering— researchers find a link between quartz and gold nuggets, and Adidas plays with living materials to make sneakers. ASM NEWS The latest news about ASM members, chapters, events, awards, conferences, affiliates, and other Society activities. 32
4 Editorial 5 Research Tracks 10 Machine Learning 6 Metals/Polymers/Ceramics 8 Testing/Characterization 11 Process Technology 46 Stress Relief 47 Editorial Preview 47 Special Advertising Section 47 Advertisers Index 48 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. 8, NOVEMBER/DECEMBER 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. 20 STRESS CORROSION CRACKING: A BRIEF HISTORICAL SNAPSHOT Russell Wanhill and Omid Oudbashi Recent archaeometallurgical studies show that stress corrosion cracking occurred in ancient metallic artifacts, a phenomenon that continues to plague modern metals. 24 TECHNICAL SPOTLIGHT FIVE KEY BENEFITS OF REMOTE MONITORING FOR LABORATORY TEST EQUIPMENT Learn how advanced technology and digitization has enabled new remote monitoring features that can increase the efficiency of any testing lab. 27 REUSE OF SPILLED-OUT METAL POWDER FROM LMD IN MAKING HYBRID MINING TOOLS Varun Kumar Kurapati and M. Kalyan Phani Enhanced mining tool performance is achieved through reclaimed NiCrBSi-WC powders in laser metal deposition that also lowers production costs and reduces environmental impact. FEATURES NOVEMBER/DECEMBER 2024 | VOL 182 | NO 8 ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2024 3 20 27 30 24 30 AI AND ML FOR MATERIALS PANEL AT IMAT 2024 Representatives from industry, government, and academia join a panel discussion on the potential that artificial intelligence and machine learning offer to the materials science and manufacturing communities.
4 ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 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 EDITORIAL COMMITTEE John Shingledecker, Chair, EPRI Beth Armstrong, Vice Chair, Oak Ridge National Lab Adam Farrow, Past Chair, Los Alamos National Lab Yun Bai, Ford Rajan Bhambroo, Tenneco Inc. Punnathat Bordeenithikasem, Machina Labs 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 Krassimir Marchev, Northeastern University Bhargavi Mummareddy, Dimensional Energy Scott Olig, U.S. Naval Research Lab Christian Paglia, SUPSI Institute of Materials and Construction Satyam Sahay, John Deere Technology Center India Abhijit Sengupta, USA Federal Government Kumar Sridharan, University of Wisconsin Vasisht Venkatesh, Pratt & Whitney ASM BOARD OF TRUSTEES Navin Manjooran, President and Chair Elizabeth Ho man, Senior Vice President Daniel P. Dennies, Vice President Pradeep Goyal, Immediate Past President Lawrence Somrack, Treasurer Amber Black Pierpaolo Carlone Rahul Gupta Hanchen Huang André McDonald Victoria Miller Christopher J. Misorski Dehua Yang Fan Zhang Veronica Becker, Executive Director STUDENT BOARD MEMBERS Gladys Duran Duran, Amanda Smith, Nathaniel Tomas 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. SUPPORTING INNOVATION In 2019, the Nobel Prize in Chemistry was awarded to a trio of inventors for their roles in the development of the lithium-ion battery: John B. Goodenough, M. Stanley Whittingham, and Akira Yoshino. Their work was supported by the U.S. Department of Energy (DOE). The DOE’s Office of Science continues to serve as the largest federal sponsor of basic research in the physical sciences. As its deputy director for science programs, Linda Horton, FASM, presented a keynote at IMAT 2024 on “Science Pathways for Energy Storage Innovation.” Horton, a pioneer herself, was the first woman to serve on the ASM Board of Trustees. She described some of the DOE’s current programs such as the Energy Earthshots, which aim to support innovation related to clean energy. Specific projects involve shots for clean hydrogen, carbon negative solutions, and long duration storage options. Another type of shot that is paying off was taken by Christopher Schuh, FASM, in founding the startup Xtalic Corp. for the development of new alloys using a groundbreaking method. In his Edward DeMille Campbell Memorial Lecture at IMAT on “The Coming Age of Computationally Designed Grain Boundary Chemistry,” Schuh raised the concern that as an industry, we have plenty of phase diagram information—but there is virtually no data on grain boundaries. In the absence of data, Schuh has encouraged his students at MIT to create models or sample equations for various alloy combinations. The Xtalic team has gone a step further in using their patented computational materials design platform to develop numerous alloys with unprecedented durability, corrosion resistance, and temperature stability. Through Schuh’s influence, the university and the startup both help to advance materials science by taking alloy development to the next level. Another professor embarking on novel research is S. Mohadeseh Taheri-Mousavi, who participated in the Artificial Intelligence and Machine Learning for Materials Panel at IMAT, summarized in this issue. She mentioned that a recent award from the U.S. Defense Advanced Research Projects Agency (DARPA) on Multiobjective Engineering and Testing of Alloy Structures (METALS) program led to her recent work in designing gradient alloys for additive manufacturing. Carnegie Mellon University, her home base, is teamed up with MIT and Lehigh University in this collaborative effort. You can read more about their work and the METALS program in our Research Tracks department. Last but not least, a highlight at the conference in Cleveland this year was the first ASM Materials Venture Challenge. Four students with entrepreneurial spirit showcased their inventions to a panel of expert judges in a “Shark Tank” format. Although one was declared the winner, all received valuable input on how to improve their products. The materials community has many ways to support innovation among its ranks. This backing can come in the form of funding, encouraging startups, collaborating across institutions, and listening to the enthusiastic ideas of our next-gen engineers. There just may be a Nobel Prize winner among them. joanne.miller@asminternational.org Deven Wells makes his pitch to Materials Venture Challenge judges.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2024 5 RESEARCH TRACKS AI AWARD TURBOCHARGES TURBOMACHINERY A new award from the U.S. Defense Advanced Research Projects Agency (DARPA) is bringing together researchers from Massachusetts Institute of Technology, Carnegie Mellon University, and Lehigh University under the Multi- objective Engineering and Testing of Alloy Structures (METALS) program. The goal is to develop design tools that optimize shape and compositional gradients in multi-material structures that complement new high-throughput materials testing techniques. A special focus area is the bladed disk (blisk) geometry found in most turbomachinery including jet and rocket engines. “This project could have important implications across a wide range of aerospace technologies. Insights from this work may enable more reliable, reusable rocket engines that will power the next generation of heavy-lift launch vehicles,” says principal investigator Zachary Cordero of MIT. “This project merges classical mechanics analyses with cutting-edge generative AI design technologies to unlock the plastic reserve of compositionally graded alloys allowing safe operation in previously inaccessible conditions.” Different locations in blisks require different thermomechanical properties and performance, such as resistance to creep, low cycle fatigue, and the need for high strength. Large-scale production also must consider cost and sustainability metrics such as sourcing and recycling of alloys in the design. Although a one-material approach may be optimal for a singular location in a com- ponent, it could leave other locations exposed to failure or may require a critical material to be carried throughout an entire part when it might only be needed in a specific location. With the rapid advancement of additive manufacturing (AM) processes that are enabling voxel-based composition and property control, the team sees that unique opportunities for advanced performance in structural components are now possible. The expertise of the researchers includes hybrid integrated computational materials engineering and machine learning-based ma- terials and process design, precision instrumentation, metrology, topology optimization, deep generative modeling, additive manufacturing, materials characterization, thermostructural analysis, and turbomachinery. mit.edu. NEW WORLD RECORD FOR X-RAYS During a collaboration with EPFL Lausanne, ETH Zurich, and the University of Southern California, View inside a state-of-the-art computer chip. Courtesy of Tomas Aidukas, PSI. researchers at the Paul Scherrer Institute (PSI), Switzerland, used x-rays to look inside a microchip with higher precision than ever before. The image resolution of four nanometers achieves a new world record. The high-resolution 3D images of the kind they produced are expected to enable advances in everything from information technology to the life sciences and materials science. Instead of using lenses, the scientists used ptychography, in which a computer combines many individual images to create a single, high-resolution picture. In this technique, the x-ray beam is not focused on a nanometer scale; instead, the sample is moved on a nanometer scale. Shorter exposure times and an optimized algorithm were key to significantly improving on the world record they themselves set in 2017. For their experiments, the researchers used x-rays from the Swiss Light Source at PSI. The new ptychographic technique is a basic approach that can be used at similar research facilities. The method is not confined to microchips, but is also well suited to other samples, for example in materials science or life sciences. www.psi.ch. A student in Zachary Cordero’s aerospace lab works with AM equipment. Courtesy of Jake Belcher/MIT.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2024 6 METALS | POLYMERS | CERAMICS Fabricated Steel Products Inc., Baton Rouge, La., will invest $3.2 million at its East Baton Rouge Parish facility. The upgrade will include a new robotic assembly and welding line that will increase production of structural steel by 50%. fsp-usa.com. flat bands generates quantum states that can be used as quantum logic gates. rice.edu. EXTRACTING GOLD FROM ELECTRONIC WASTE Scientists have found a way to remove gold from electronic waste that’s much more efficient than conventional methods as well as cheaper and cleaner. A team of chemists and materials scientists from the National University of Singapore, in collaboration with researchers from Manchester University, U.K., and Guangdong University of Technology, China, developed a type of sponge made of graphene oxide and chitosan to use for gold extraction. Graphene has a demonstrated ability to absorb ions, and chitosan is a natural biopolymer and well-known reducing agent, in this case used to catalytically convert gold ions into their solid form. The two materials were made into a composite by allowing the chitosan to self-assemble on 2D graphene flakes—a process that also KAGOME METALS DEFY MAGNETIC THEORIES Reshaping scientific understanding of magnetism and electronic interactions in cutting-edge materials, a new discovery by Rice University, Houston, researchers could revolutionize advanced tech applications. Physicists and collaborators studied iron-tin (FeSn) thin films to gain new insights into kagome magnets—materials named after an ancient basket-weaving pattern and structured in a unique, latticelike design that can create unusual magnetic and electronic behaviors due to the quantum destructive interference of the electronic wave function. The findings reveal that FeSn’s magnetic properties arise from localized electrons, not the mobile electrons scientists previously thought. Using an advanced technique that combines molecular beam epitaxy and angle-resolved photoemission spectroscopy, the researchers created high-quality FeSn thin films and analyzed their electronic structures. They found that even at elevated temperatures, the kagome flat bands remained split, an indicator that localized electrons drive magnetism in the material. This electron correlation effect adds a new layer of complexity to understanding how electron behavior influences magnetic properties in kagome magnets. The study also revealed that some electron orbitals showed stronger interactions than others, a phenomenon known as selective band renormalization—previously observed in iron-based superconductors—offering a new perspective on how electron interactions influence the behavior of kagome magnets. Beyond advancing the understanding of FeSn, the research has broader implications for materials with similar properties. Insights into flat bands and electron correlations could influence the development of new technologies such as high-temperature superconductors and topological quantum computation, where the interplay of magnetism and topological Specialty metals distributor Vested Metals, St. Augustine, Fla., opened a sales and service center in Fort Wayne, Ind. The 20,000-sq-ft facility features state-of-the-art processing saws for precision cutting as well as tumbling services to refine product finishes. vestedmetals.net. BRIEFS From le : Ming Yi and Zheng Ren led a new study on iron-tin thin films that reshapes scientific understanding of kagome magnets. Courtesy of Je Fitlow/Rice University. SEM image of Au3+ extraction and reduction by GO/chitosan sponge; Au3+ is shown in yellow. Courtesy of Kou Yang.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2024 7 resulted in the formation of sites on the material that could bind to gold ions. After the gold ions are absorbed into the graphene, the chitosan converts them into their solid gold state, allowing for easy collection—a process the research team describes as highly efficient. The team tested their sponge using real e-waste provided by a recycling company. Measurement prior to treatment showed gold concentrations of 3 ppm. The newly developed sponge was able to extract approximately 17g/g of Au3+ ions and a little more than 6 g/g of Au+. Such amounts, the team claims, are approximately 10 times that of any other known extraction process. www.manchester.edu, www.nus.edu.sg, www.english.gdut.edu.cn. LONG SPIN RELAXATION PROVIDES SPINTRONIC INSIGHTS At Osaka Metropolitan University in Japan, a research group is studying spin currents for implementation in next-generation technology such as memory devices. To investigate the characteristics of spin currents, Professor Katsuichi Kanemoto’s group designed a multilayer device consisting of a ferro-magnetic layer and an organic semiconductor material. By adopting a doped conducting polymer with a long spin relaxation time, the team succeeded in observing the effects of spin transport and spin current generation from the non-magnetic, organic semiconductor side. The long spin relaxation times not only equate to more efficiency in spintronics but also enable direct observation of phenomena due to spin current generation in the organic layer side. Moreover, the researchers were able to find that—contrary to a widely accepted theory—the width of the ferro-magnetic resonance measurements for the layer of the spin current supplier slightly narrowed in the device system using the organic semiconductor with a long spin relaxation time. www.omu.ac.jp/en. Measurements of spin currents in the hybrid interface of a device with a ferro-magnetic (Py) layer and an organic semiconductor (PANI) layer. Courtesy of Osaka Metropolitan University. One Part Supreme 10HT for STRUCTURAL TOUGHENED EPOXY BONDING Hackensack, NJ 07601 USA • +1.201.343.8983 • main masterbond.com www.masterbond.com HIGH BOND STRENGTH Lap shear strength | 3,600-3,800 psi Tensile modulus | 450,000-500,000 psi NASA LOW OUTGASSING Per ASTM E595 standards SERVICE TEMPERATURE RANGE From 4K to +400°F
8 ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2024 solved the complex structure of aluminum oxide’s (Al2O3) surface, a puzzle listed in 1997 as one of the three mysteries of surface science. Also known as alumina, corundum, sapphire, or ruby, aluminum oxide is one of the best insulators used in a wide range of applications—in electronic components, as a support material for catalysts, or as a chemically resistant ceramic, among others. Knowledge of the precise arrangement of surface atoms is key to understanding how chemical reactions occur in this material, such as those in catalytic processes. On the surface, however, the structure deviates from that inside the crystal, and the strongly insulating nature of alumina has hindered experimental studies. The research team used noncontact atomic force microscopy (ncAFM) to analyze the surface structure. This method generates images of the TESTING | CHARACTERIZATION UNLOCKING QUANTUM MATERIALS POTENTIAL A new way to observe changes in materials at the atomic level was created by a research team at the DOE’s Oak Ridge National Laboratory, Tenn. The unique method opens new avenues for understanding and developing advanced materials for quantum computing and electronics. The new rapid object detection and action system, or RODAS, combines imaging, spectroscopy, and microscopy methods to capture the properties of fleeting atomic structures as they form, providing novel insights into how material properties evolve at the smallest scales. Traditional approaches combining scanning transmission electron microscopy, or STEM, with electron energy loss spectroscopy, or EELS, have been limited because the electron beam can change or degrade the materials being analyzed. RODAS overcomes this challenge and also integrates the system with dynamic computer vision enabled imaging, which uses real-time machine learning. When analyzing the specimen, RODAS focuses only on areas of interest. This approach enables rapid analysis—in seconds or milliseconds— compared to the sometimes several minutes required by other STEM-EELS methods. Importantly, RODAS extracts crucial information without destroying the sample. The RODAS technique represents a significant leap forward in materials characterization. It empowers researchers to dynamically explore structure-property relationships during analysis, target specific atoms or defects for measurement as they form, efficiently collect data on various defect types, adapt to identify new atomic or defect classes in real time, and minimize sample damage while maintaining detailed analysis. ornl.gov. LONG-STANDING ALUMINA MYSTERY SOLVED Researchers at Austria’s TU Wien and the University of Vienna have The structure of the aluminum oxide surface was determined with noncontact atomic force microscopy and computational modeling. Courtesy of Johanna Hütner, David Kugler, and Jan Balajka. Using deep learning in real time, specific sites of interest (colored circles) can be measured via electron microscopy. Courtesy of Kevin Roccapriore and Scott Gibson/ ORNL, U.S. DOE. Bruker Corp., Billerica, Mass., introduced a new benchtop metal analyzer. The Q6 Newton benchtop spark optical emission spectrometer is designed to significantly improve alloy composition analysis in the metals industry. bruker.com. Leica Microsystems Inc., Deerfield, Ill., launched a new online shopping platform with an AI search function for some of its microscopes. Users can compare features, review pricing, place an order, or request a quote. leica-microsystems.com BRIEFS
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2024 9 surface structure by scanning a sharp tip mounted on a quartz tuning fork at a close distance from the surface. The frequency of the tuning fork changes as the tip interacts with the atoms on the surface without touching the material. In an ncAFM image, the researchers explain, they can see the location of atoms, but not their chemical identity. The team overcame the lack of chemical sensitivity by attaching a single oxygen atom to the tip apex, allowing them to distinguish between oxygen and aluminum atoms on the surface. The 3D model of the aluminum oxide surface was optimized with machine learning methods. “Through the collaborative effort of experimental and computational research, we not only tackled a long-standing mystery by determining the detailed structure of this enigmatic insulator, but also discovered structure design principles applicable to an entire class of materials,” says lead researcher Jan Balajka. www.tuwien.at/en, www.univie.ac.at/en. REVERSE ENGINEERING COMPOSITES WITH AI Creating new materials for modern needs typically involves tuning mechanical properties in one direction. Now, using artificial intelligence and machine learning, researchers at Binghamton University, N.Y., are exploring ways to design materials that remain strong when facing stress from multiple directions. Funded by a grant from the National Science Foundation, the researchers are developing a deep-learning model informed by the principles of physical laws that can customize the microarchitecture of composite materials. Lead researchers Mir Jalil Razavi and Dehao Liu will develop thousands of mechanical computational models to train deep learning algorithms in designing composite materials tailored to specific mechanical behavior requirements. They will decide which suggestions are most promising, and their Deep-learning models can customize microarchitecture based on specific needs. Courtesy of Watson College. collaborator, Yanyu Chen from the University of Louisville, Ky., will validate the best combinations through additive manufacturing, x-ray imaging, and stress testing. The Binghamton team believes this research could revolutionize materials design and enable the rapid development of new highly tailored materials. www.binghamton.edu. thermcraftinc.com • (336) 784-4800 Industrial& Laboratory Furnaces, Ovens& Heaters • Batch or Continuous Processing • Durable Construction • Standard or Fully Customizable • Up to 1800ºC, 3272ºF • Single or Multi-Zone • PLC Controls Available • Made in the USA Since 1971 thermcraftinc.com • (336) 784-4800 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
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2024 10 MACHINE LEARNING | AI The Argonne Leadership Computing Facility (ALCF) at the DOE’s Argonne National Laboratory is offering researchers access to a collection of AI machines called the ALCF AI Testbed where AI accelerators handle a variety of tasks including AI model training, inference, large language models, and more. anl.gov. BRIEF AI-DRIVEN SYSTEM SPEEDS MANUFACTURING Researchers at the University of Virginia (UVA), Charlottesville, report a significant advancement in manufacturing technology by developing an AI-driven system that could transform how factories run. Using multi-agent reinforcement learning, the team created a more efficient way to optimize manufacturing systems, improving speed and quality while reducing waste. Their approach integrates AI agents that work together to optimize production processes. By coordinating multiple agents to manage tasks in real time, the system adjusts automatically, improving performance over time. The team’s algorithms, credit- assigned multi-agent actor-attention-critic and physics-guided multi-agent actor-attention-critic, were key in making this advancement. These algorithms allow the system to account for both the physical constraints of machinery and unpredictable production disruptions. Their work has shown notable improvements in both productivity and system robustness. The research was conducted in collaboration with General Motors, a key industry partner that provided valuable insights and real-world applications for the AI system. GM’s involvement helped ensure that the technology addresses the practical challenges of modern manufacturing. “Our collaboration with UVA allowed us to explore innovative solutions that could transform production efficiency across the automotive industry,” says GM researcher Hua-Tzu Fan. virginia.edu. MACHINE LEARNING FOR POLYCRYSTALLINE MATERIALS Researchers at the University of California, Irvine and other international institutions achieved atomic-scale observations of grain rotation in polycrystalline materials, reportedly for the first time. Using state-of-the-art microscopy tools at the UC Irvine Materials Research Institute, scientists heated samples of platinum nano- crystalline thin films and observed the mechanism driving grain rotation in exceptional detail. The study used advanced techni- ques such as 4D Researchers at UVA and GM are working together on AI-driven systems for smarter, faster, and more adaptable automotive manufacturing. scanning transmission electron microscopy (STEM) and high-angle annular dark-field STEM. To address the challenge of interpreting the large 4D-STEM datasets, the authors developed a machine learning-based algorithm to extract critical information. These powerful imaging and analysis tools provided direct, real-time views of the atomic processes involved, specifically highlighting the role of disconnections at grain boundaries. The team discovered that grain rotation in these substances occurs through the propagation of disconnections, line defects with both step and dislocation characteristics, along the grain boundaries. This insight significantly advances understanding of the microstructural evolution in nanocrystalline materials. With the machine learning-assisted data analysis, the study also revealed for the first time a statistical correlation between grain rotation and grain growth or shrinkage. This relationship arises from shear- coupled grain boundary migration driven by disconnection motion, as confirmed by STEM observations and supported by atomistic simulations. Researchers say this finding is pivotal as it not only illuminates the fundamental mechanisms of grain rotation but also offers insights into the dynamics of nanocrystalline materials. uci.edu. Measurement of residual strain at the Σ11 GB before and after GB migration. Courtesy of Science, 2024, doi.org/10.1126/science.adk6384.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2024 1 1 PROCESS TECHNOLOGY SYNTHESIZING DISORDERED MATERIALS Researchers from the University of British Columbia (UBC) have discovered how different synthesis methods impact the structural and functional properties of high-entropy oxides, a material used in electronic devices. These materials are promising due to their chemical flexibility and electrochemical properties. The team focused on a high- entropy oxide with a spinel crystal structure, which is a mixture of five different transition metal oxides. They prepared identical samples using five synthesis methods—solid state, high pressure, hydrothermal, molten salt, provides a deeper understanding of material strength, which could have a wide-ranging impact on materials design and manufacturing. However, it’s been difficult to study this process in real time, as atomic-scale observation typically requires electron microscopes, limiting researchers to before-and-after snapshots. To address this, the SEAS team used colloidal crystals—particles 10,000 times larger than atoms that mimic atomic systems. These crystals form similar structures, undergo comparable phase transitions, and display the same defects as atomic systems, making them ideal for studying work hardening. Despite being extremely soft—100,000 times softer than Jell-O—these crystals displayed strong work hardening, even more significant than many metals. When adjusted for particle size, they became stronger than most metals. The study revealed that the geo- metry of particles and the density of defects primarily govern work hardening. These findings provide a universal understanding of the process, generally applicable to all materials, even those that cannot be directly studied with optical microscopes. The research highlights the potential for developing stronger, more resilient materials across various fields including engineering and manufacturing. seas.harvard.edu. and combustion syntheses. Each method involves different heating and cooling processes and chemical conditions. The key difference between the synthesis methods is the driving mechanism that forms the material, says lead researcher Mario Ulises González-Rivas. In the solid-state method, metal oxides are mixed and then heated, similar to baking a cake. The high pressure method adds external pressure during heating, which can influence how the material forms. The hydrothermal method mimics mineral formation in Earth’s core by heating metal salts in water inside a pressurized vessel, creating a flow that helps crystals grow. The molten salt method uses melted metal salts, which form a thick liquid that, as it cools, allows crystals to precipitate. Lastly, the combustion method involves dissolving metal salts in water, forming a gel that ignites, rapidly producing the desired material through a quick combustion reaction. “Our results confirm that the synthesis method matters a great deal,” conclude the researchers. “We found that while the average structure is unaltered, the samples vary significantly in their local structures and their microstructures with the combustion synthesis resulting in the most homogeneous samples.” www.ubc.ca. WORK HARDENING MECHANISMS REVEALED For the first time, scientists have observed the detailed mechanisms behind work hardening using colloidal crystals. A team of researchers from Harvard University’s School of Engineering and Applied Sciences (SEAS), Cambridge, Mass., grew these crystals, composed of millions of particles, and tracked their movement with a confocal optical microscope. It’s the first time that work hardening has been observed in colloidal crystals. The team’s work Vianode, a battery materials manufacturer, opened its first full-scale anode graphite production plant called Via ONE in Heroya, Norway. The facility has four furnaces specifically designed to produce synthetic anode graphite for lithium-ion batteries, with an annual capacity of 2000 tons. vianode.com. BRIEF Metal oxides are mixed and then heated during the solid-state method. Courtesy of UBC. A snapshot of the von Mises equivalent strain, calculated for γ ≈ 0.06, after the onset of the localization of flow. Courtesy of Harvard SEAS.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2024 12 *Member of ASM International Photograph of a neutron di raction residual stress measurement on an aluminum alloy T-section at the High Flux Isotope Reactor, a DOE O ice of Science User Facility operated by the Oak Ridge National Laboratory. Courtesy of Hill Engineering. RESIDUAL STRESS Optimize a residual stress measurement plan by understanding the methods, basic knowledge, and how to use the measured data. HOW RESIDUAL STRESSES ARE MEASURED—AN OVERVIEW Iuliana Cernatescu* Pratt & Whitney, East Hartford, Connecticut James Pineault* Proto Manufacturing, Taylor, Michigan
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2024 13 Residual stress is generally defined as the stress that is retained in equilibrium in a body or material after manufacturing or processing operations or component usage in the absence of any external forces. Residual stresses can be purposefully engineered into components with the goal of extending component perfor- mance beyond the material and structural capability, or they can be unintentionally introduced by the manufacturing or assembly process. In each case, the measurement of residual stress is critical input for process optimization, life predictions, and quality control. An overview of most known origins of residual stresses is listed in Fig. 1[1,2]. Looking at the length-scale in which residual stresses reach equilibrium, the residual stresses in crystalline materials can generally be categorized as: a) type I, also called macro-stresses, where the equilibrium is reached over macroscopic lengths; b) type II or intergranular stresses where the equilibrium is reached over the length of few grains; and c) type III, also called micro-stresses or intragranular stresses, where the equilibrium is reached within a grain over the distance of few atomical planes. Type III stresses are generated by local atomic defects such as vacancies, interstitials, or dislocations. This classification of residual stress types is schematically illustrated in Fig. 2. These definitions are also important to keep in mind when planning measurements, as different techniques interrogate different volumes and length-scales. Therefore, the results are relevant within the context of the interrogated volume[3-5]. When planning residual stress measurements, it is important to keep the application in mind: How will the residual stress data be used? Why do we want to understand the residual stresses that may be present? These questions are fundamental when evaluating applicability of the measurement tools, and when optimizing Fig. 1 — Origin of residual stresses can be generally created by three major processes: manufacturing or assembly processes, microstructure driven, or in-operation process induced. Fig. 2 — Illustration of residual stress/strain types in a polycrystalline material.
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2024 14 the measurement plan. As with every measurement system, getting accurate and precise data at the same time may be either challenging, costly, or both. Furthermore, each measurement methodology comes with various assumptions, strengths, and limitations. In general, residual stress measurements are used in one of the following applications: a) residual stress predictive model validation or calibration; b) failure investigation; c) process opti- mization; d) component life assessment; and e) quality control. In the case of model calibration and validation, failure analysis, and component life assessment, accuracy is important; whereas, precision is more relevant in process optimization and quality control[1]. OVERVIEW OF RESIDUAL STRESS MEASUREMENT METHODS It is important to clarify that none of the residual stress measurement methods measure residual stress directly. All measurement methods rely on the measurement of a feature resulting from the presence of residual stress, and use physics-based models or calibrations to convert that feature into residual stress values given various assumptions. It is important to note that stress, and therefore residual stress, is defined by a tensor. To define the complete strain tensor, at least six stress components must be measured. Given time and resource restrictions or measurement method limitations, the residual stress state is assumed to be uniaxial, biaxial, or pseudo-triaxial. Regardless of underlying assumptions, each method uses Hooke’s law to convert strain into residual stresses. DIFFRACTION-BASED METHODS Residual stress measurement by diffraction methods is based on the fact that x-ray or neutron diffraction methods can measure distances between atomic planes, also called d-spacings. The resulting diffraction beam angle 2θ may be measured relative to the angle of the incident beam, which can be directly related to the atomic d-spacing using Bragg’s law, nλ = 2d sin θ. Here, λ is the wavelength of the incident x-rays or neutrons, d is the atomic plane spacing, and 2θ is the angle subtended by the incident and diffracted beams. Figure 3a illustrates a diffraction experiment in a stressfree material where for a given d-spacing and incident x-ray wavelength, λ, the diffracted beam is measured at a 2θ angle from the incident beam. Figure 3b shows that in the presence of residual or applied stresses the material will experience a change in the d-spacing which results in a shift of the diffraction peak angle relative to stress-free state. Figure 3c shows the diffraction peak shift resulting from the presence of residual or applied stresses can be measured in a diffractogram[2-6]. Note that electron diffraction can also be used to measure residual stress, but due to the localized nature of electron diffraction this technique can only capture type III stress/strains. This method is generally used to determine the geometrically necessary dislocations (GND). When using laboratory x-ray diffraction systems, a variety of configurations and techniques can be used including the sin2φ, cos α, and multiple hkl approaches, as well as single crystal and epitaxial thin film methods[1,2]. When using a synchrotron source of x-rays, residual stress measurements may be performed in either energy dispersive or angular dispersive set-ups[3-6]. Specialized techniques to characterize type II and III stresses include high energy diffraction microscopy (HEDM), three-dimensional x-ray diffraction (3DXRD)[7], point- focused high energy diffraction microscopy (PF-HEDM)[8], and dark field x-ray microscopy (DFXM)[9]. Neutron diffraction residual stress measurements can be collected in either continuous beam or time-pulsed beam[10-13]. Diffraction-based measurement methods have several variations based on the type of radiation used and diffraction conditions. Laboratory-based methods generally have a relatively shallow (few microns in metals) penetration depth; therefore, probing residual stresses deeper into the sample requires material removal. Correspondingly, this material removal is generally considered either destructive or semi- destructive since the final product must be physically altered locally. However, Fig. 3 — Simplified illustration of the impact on measured diffraction peak in the presence of residual or applied stresses. (a) Diffraction from a stress-free material. (b) Diffraction shift due to applied or residual stress. (c) Diffractogram of stress-free and stressed material where, due to tensile stress present, diffraction peak shifts from the stress-free diffraction peak position. (a) (b) (c)
ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2024 15 synchrotron-based methods can be performed in a nondestructive manner up to a few centimeters deep into metals. The maximum achievable penetration depth depends on the material type and geometry of the test article. Synchrotron-based methods also have the advantage of being able to probe relatively small volumes, on the order of tens of micrometers depending on material type, component, and diffraction geometry. Neutron diffraction methods can generally penetrate deeper than synchrotron-based methods; however, interrogated volume is on the order of millimeters[1-13]. Here, it is important to note that with recent developments in laboratory-based high energy sources and detectors, laboratory diffraction-based methods could become nondestructive to greater depths than conventional methods. Table 1 gives a summary of diffraction-based residual stress measurement methods and measurement features used by each specific technique. TABLE 1 — DIFFRACTION-BASED AND PIEZO-SPECTROSCOPIC/RAMAN METHODS Diffraction based Piezospectroscopic Method Laboratory x-ray diffraction Synchrotron x-ray diffraction Neutron diffraction Raman What is measured? Bragg diffraction peaks position Bragg diffraction peaks position Bragg diffraction peaks position Raman shift Gauge Atomic planes spacing Atomic planes spacing Atomic planes spacing Atomic spacing Typical volume analyzed 1-2 mm Ø × 5-10 µm Few tens of micrometers 1 mm × 1 mm × 1 mm ~1 µm Ø × 1 µm Smallest volume analyzed 100 µm Ø × 5-10 µm ~10 µm × 10 µm × 5 mm (energy dispersive) ~100 µm × 100 µm × 100 µm (angle dispersive) Sub-grain volumes with specialized optics ~300 µm × 300 µm × 300 µm ~1 µm Ø × 1 µm Depth resolution ~50 µm* ~50 µm* ~50 µm* <1 µm Spatial lateral resolution ~50 µm* ~50 µm*, 1 µm with specialized optics/techniques ~50 µm* ~1 µm Overall depth achievable destructively Up to 1-2 cm using layer removal and corrections Several centimeters Tens of centimeters - Certain materials can become radioactive in which case the part/ sample is quarantined till cleared Method only used surface-wise Overall depth achievable nondestructively 5-25 µm using conventional or grazing angle diffraction methods Material dependent, 1-5 cm in energy dispersive set-ups and 0.5 cm in angle dispersive set-ups ~10 cm material dependent ~1 µm Stress types Type I, II, III Type I, II, III Type I, II, III Type I, II, III Stress state measurable Uniaxial, biaxial, triaxial Uniaxial, biaxial, triaxial Uniaxial, biaxial, triaxial Uniaxial, biaxial Measurable materials Crystalline materials: Metals, plastics, ceramics Crystalline materials: Metals, plastics, ceramics Crystalline materials: Metals, plastics, ceramics Plastics, ceramics Accuracy ±10 MPa ±10 × 10-6 strain < 100 × 10-6 strain ±50 MPa Precision ±5 MPa ±10 × 10-6 strain ~100-150 × 10-6 strain ±50 MPa * Stage and instrumentation dependent
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