Above: Elmet Technologies is one of several producers of high-performance metals that supplied components to the Artemis program, whose mission is a manned moon landing.
February 2023- Discoveries about materials, their fluid properties and evolving applications fuel dreams of tomorrow From deep space to extracting cores from deep in the earth, a variety of experiments and explorations are going on to help humankind understand how to create better products in more efficient ways without harming the world around us. Modern Metals has gathered information about a few promising developments.
NASA PROGRAM
Elmet Technologies, which manufactures high-performance tungsten and molybdenum components for aerospace applications, supplied ballast weights for the Orion Space Capsule, used in the National Aeronautics and Space Agency’s Artemis I program. Artemis I launched the Orion spacecraft Nov. 16, which flew 1.4 million miles around the moon and splashed down Dec. 11 in the Pacific Ocean near Baja, California. In the next mission (Artemis II), astronauts will land on the moon for the first time in 50 years.
Elmet expects to provide ongoing support for tungsten manufacturing and testing needs for its aerospace customers. Other programs involving Elmet Technologies’ components include Dragonfly, a proposed spacecraft and mission that would send a mobile robotic rotorcraft lander to Titan, the largest moon of Saturn, in order to study prebiotic chemistry and extraterrestrial habitability. Dragonfly is set to launch in 2026 and land on Titan in 2034.
COATINGS, PART I
Arizona State University mechanical engineering and materials science researchers, alongside the DEVCOM Army Research Lab, have produced a new surface treatment for metal alloys that enhances corrosion resistance against multiple environmental factors.
Corroded materials lead to major problems requiring expensive repairs and replacement of technology used in manufacturing operations, oil and gas pipelines, and chemical plants and public utilities, not to mention defense assets.
Kiran Solanki, professor in the School for Engineering of Matter, Transport and Energy at ASU’s engineering department, worked with his student Vikrant Kumar Beura, who graduated with a doctorate in materials science.
“We designed a treatment to enhance the performance of alloys and give them a longer life span,” Solanki says. “Our patent-pending process changes the surface morphology of metallic alloys in ways that enable them to perform better in aggressive environments.”
The treatment improves corrosion resistance without a loss of strength, and it works especially well on aluminum-based alloys used in the aerospace, automotive and naval industries.
“We learned to change the morphology of the surface of a metal alloy by either changing the internal microstructure or by adding different alloy elements,” Solanki says. The surface treatment alters the internal microstructure and oxide layers of alloys, making their surfaces more resistant to gases, liquids, salts, acids and varying temperatures that cause corrosion. Spacecraft, aircraft, ships and ground vehicles are each likely to need specific combinations and applications of treatments to best protect them from wear and tear in the different environments and conditions in which they are used.
COATINGS, PART II
Professor Myeong-Hoon Lee, head of the Center of Surface Corrosion Control Engineering at Korea Maritime and Ocean University, and his colleagues have proposed a novel coating for steel that promises to increase its longevity.
During my time in the Navy, I noticed a lot of machines were rusting. So I engaged in this research, hoping to produce better anticorrosive steel,” says Lee, adding that increasing steel’s life span makes it more sustainable.
Lee’s published research paper proposes coatings comprising three layers fabricated using physical vapor deposition. A zinc–magnesium layer is sandwiched between two zinc layers.
The top zinc layer protects the Zn–Mg layer from being in contact with the corrosive environment. The last line of defense for the steel is the bottom zinc layer. Two samples were prepared to test the corrosion resistance of this coating—one containing 10 percent magnesium and the other 25 percent magnesium. The team found that signs of rust appeared at 208 hours and 408 hours for the 10 percent and 25 percent compositions, respectively, when compared with 96 and 120 hours for conventional zinc coatings. The researchers found the 25 percent Mg composition had a higher resistance to rust than the 10 percent Mg coating. This contradicts previous studies suggesting Mg content higher than 8 percent lowers the corrosion resistance of steel.
“The multilayer coating on steel makes it highly stable, economical and durable,” Lee says.
MYEONG-HOON LEE, KOREA MARITIME AND OCEAN UNIVERSITY
A. Arizona State University tests a new surface treatment to prevent rust
B. VulcanForms digital factory
C. KGHM Polska Miedź SA is using AI to minimize heat loss in its furnaces
D. Elmet Technologies’ tungstenmolybdenum components for aerospace.
E. Rio Tinto and Canada will work together to decarbonize mining operations in Quebec.
DECARBONIZATION, PART I
Rio Tinto is partnering with the government of Canada to invest up to U.S. $550 million over the next eight years to decarbonize its Rio Tinto Fer et Titane operations in Sorel-Tracy, Québec. The partnership will support technological innovations that represent a first step toward reducing greenhouse gas emissions from the mining complex’s titanium dioxide, steel and metal powders business by up to 70 percent.
“Rio Tinto is committed to being part of a net-zero future, from decarbonizing our operations to finding new ways to produce the materials needed for the transition,” says CEO Jakob Stausholm.
The partnership will support projects like BlueSmelting, an ilmenite smelting technology that could generate 95 percent less GHG than Rio Tinto’s current reduction process, enabling the production of high-grade titanium dioxide feedstock, steel and metal powders with a drastically reduced carbon footprint.
Construction of a demonstration plant, which will be able to process up to 40,000 metric tonnes of ilmenite ore per year, should ramp up during the first half of 2023.
Secondly, Rio Tinto and others will work together to develop a new process for extracting and refining titanium. A pilot plant at the Sorel-Tracy metallurgical complex is being built to validate a low-cost process that requires no harmful chemicals and does not generate direct GHG. The pilot plant is expected to open by year’s end.
DECARBONIZATION, PART II
Researchers at Colorado School of Mines and Virginia Tech won a $1.15 million grant from the U.S. Department of Energy for research toward developing new technology that will enable mining companies to quantitatively model the carbon sequestration potential of copper-nickel-platinum group element ore deposits.
Led by Thomas Monecke, Colorado’s professor of geology and geological engineering, researchers will seek to increase the mineral yield and domestic supply of copper, nickel, cobalt and other critical elements, while lowering the required energy—and subsequent emissions—to mine and extract these minerals.
“[We plan to] develop a technological solution that will allow mining companies to quantitatively evaluate whether adaption of net-zero or net-negative emission technology is economically feasible,” says Monecke. For this project, the research team at Mines and Virginia Tech will work with industry partner Minalyze AB, which designed continuous X-ray fluorescence core scanning technology. Based on the geochemical analysis of drill cores, researchers will devise machinelearning algorithms to help quantify the relative proportions of CO2-reactive minerals contained in the core.
A thermodynamic modeling algorithm will then be developed to quantify the amount of CO that can be sequestered into rock formations of variable mineralogy. As a final step, researchers will develop a method for block modeling to determine the total amount of CO that could be sequestered into an entire ore deposit.
ARTIFICIAL INTELLIGENCE KGHM
Polska Miedź SA, a Polish mining company, says that a project to implement algorithms supporting the work of flash furnace operators at its Głogów copper smelter has been completed.
The AI algorithms, based on historical data, predict with almost 100 percent effectivity, the heat loss in the reaction shaft of the furnace.
The flash furnace is the heart of the Głogów smelter; it is constantly monitored and its temperatures reach 1,300 degrees Celsius. The challenge—to stabilize the heat pick-up in the reaction shaft—was given to computer programmers and analysts, who began their work in 2021. The results were so promising that the mining company implemented the predictive heat-regulation solution within five months.
HEAT TREATING
A new heat treatment, developed by researchers at the Massachusetts Institute of Technology, transforms the microscopic structure of 3D-printed nickel-based superalloys, making them stronger and more resilient in extreme thermal environments. The technique could make it possible to 3D print high-performance blades and vanes for power-generating gas turbines and jet engines, which would enable new designs with improved fuel consumption and energy efficiency.
Efforts to print turbine blades, rather than cast them, have faced creep, which is metals’ tendency to deform in the face of persistent mechanical stress and high temperatures. Researchers found the printing process produces a microstructure that is especially vulnerable to creep, which means a shorter life span for the blade or lower fuel efficiency.
But by adding an additional heat-treating step, which transforms the as-printed material’s fine grains into much larger columnar grains, the sturdier microstructure that results should minimize creep. The researchers say the method clears the way for industrial-scale printing of gas turbine blades. “Gas turbine manufacturers will print their blades and vanes at large-scale additive manufacturing plants, then post-process them using our heat treatment,” predicts Zachary Cordero, an aeronautics professor at MIT.
DIGITAL MANUFACTURING
VulcanForms, an MIT-hatched company that builds and operates digital manufacturing infrastructure, has built two digital production facilities in Massachusetts in order to capture the full value chain for precision metal components and assemblies.
One factory is powered by a fleet of VulcanForms’ proprietary 100-kW laser powder bed fusion additive manufacturing systems, and the second focuses on automated precision machining and assembly operations.
Digital-first production technologies, including additive manufacturing, enable more innovative, resource efficient and resilient supply chains than a lot of traditional brick-and-mortar operations. The company has hired experts from Alcoa, AutoDesk, Google, General Electric, Pratt & Whitney, Precision Castparts, IPG Photonics, Schlumberger and others, who are working together to bring forth metal additive manufacturing as a scalable industrial process, and as a cornerstone of breakthrough digital production systems.
The Orion spacecraft flew 1.4 million miles around the moon and splashed down Dec. 11 in the Pacific Ocean
“VulcanForms’ full-stack approach to deliver an engineered solution, combining advanced additive and subtractive technologies merged through a digital thread, will revitalize U.S. manufacturing and hardware innovation,” claims Greg Reichow, a company director. “The technologies that enable this agile workflow will dramatically impact the way products are imagined, designed, built and delivered for decades to come.”
X-RAY VISION
For aircraft, cargo ships, nuclear power plants and other critical technologies, a corrosion-resistant alloy called 17-4 precipitation hardening (PH) stainless steel is often specified. Grade 17-4 PH stainless steel can now be consistently 3D printed while retaining its favorable characteristics, thanks to researchers from the National Institute of Standards and Technology (NIST), University of Wisconsin–Madison and Argonne National Laboratory. NIST physicist Fan Zhang, a study co-author, says the fast heating and cooling rates during 3D printing make it difficult to measure what’s happening. The crystal structure of the atoms within the material “shifts rapidly and is difficult to pin down,” Zhang says.
The team used synchrotron X-ray diffraction (XRD) and the Advanced Photon Source, an 1,100- meter-long particle accelerator at Argonne National Lab, to smash high-energy X-rays into steel samples during printing. They mapped out how the crystal structure changed over the course of a print, revealing how certain factors they had control over—such as the composition of the powdered metal—influenced the process throughout.
Now equipped with a clear picture of the structural dynamics during printing as a guide, the researchers were able to fine-tune the makeup of the steel to find a set of compositions— including just iron, nickel, copper, niobium and chromium—that did the trick.
“Composition control is truly the key to 3D printing alloys. By controlling the composition, we are able to control how it solidifies,” Zhang says.
Mechanical testing showed that the 3D-printed steel, with its martensite structure and strengthinducing nanoparticles, matched the strength of steel produced through conventional means.
HIGH-ENTROPY ALLOYS
High-entropy alloys are a new class of alloys that are composed of four or more metallic elements in roughly equal amounts. For example, commercial aluminum alloys typically consist of more than 95 percent aluminum. Although they may contain other elements (copper or magnesium), these are minor additions. In the case of a high-entropy alloy, however, the amounts of aluminum, copper and magnesium would be nearly equal.
Helen Chan, professor of materials science and engineering at Lehigh University, says some highentropy alloys “have already been demonstrated to exhibit surprisingly good properties [such as] excellent mechanical properties at elevated temperature. But we’re really just scratching the surface.”
VulcanForms started up two industrialscale metals additive manufacturing plants in Massachusetts.
In many cases, however, fabricating these alloys begins in the molten state and requires very high temperatures which is difficult both from an experimental and industrial perspective and, often, the compositional makeup of the resulting material isn’t uniform “so you don’t get the alloy and the properties that you think you’re going to get,” Chan explains.
Chan and her colleagues won a grant from the National Science Foundation to explore a novel fabrication method that involves reducing a mixture of the metallic oxides. The process uses lower temperatures and a different reaction route to achieve a more homogenous microstructure. The potential also exists to develop microstructures and properties that are not achievable through conventional arc-melting processes.
“In the process we are studying, we are reducing a mixture of oxides to get a metallic alloy at the end, which isn’t often done,” says Chan. Further experiments will test for different reduction conditions “and help contribute to the thermodynamic database for these materials.”
“As materials engineers, we’re always trying to develop new materials that can operate at higher temperatures these could be used in engine components or parts of aerospace vehicles,” says Chan. “So substituting high-entropy alloys for the superalloys being used now would enable jet engines to be more fuel efficient and produce less greenhouse emissions. MM
